| GeorgeBoles |
Evening All,
I am loathe to start a thread headed something like,"Which pre-amp should I build?" but it has reached the point where I need this advice from knowledgable persons. The permutations and combinations are endless.
Currently:
I have Linkwitz Orion speakers ... an active crossover design. The crossovers are full of opamps (OPA2134 or similar, 22 per channel!). The inputs and outputs to the crossovers are all unbalanced. Currently each driver is powered by its own LM3886 chip-amp, and I have a dual rail "clone" of the NS10 as the pre-amp.
But I recently heard a system in Melbourne which makes me realize I could be striving for a LOT more, and so the audiophilia has struck again.
Power Amp Plan
I plan to build 4 channels of Babelfish-J-X (30W) for tweeters and midrange, and keep my chipamps for the woofers of the Orions. (This was decided after some agony, because I really wanted to build Aleph3/Bablefish-J for the tweeters, but everything I read makes me think the X-ed DIY amps have more presence and less "nice colouration". I might have to move up to a 60W Aleph-X DIY design if the 30W is a bit underdone for the mid-range ... shouldn't be, but one cannot tell.) I have all the expensive parts, but have not purchased the transformers for these yet, so if my thinking is woolly, please let me know now!
Options I have considered for Pre-amp are:
1. CCS-X-Bosoz: lots of discussion on this board; some apparently built and sound good :). I have the mosfets for this.
2. Aleph P1.7: an original Pass design - gotta be good, even if I only get it half right :cool:. In fact a good supply of mosfets for this, but it lacks this years "cool" product ... jfets!
3. The Jfet BOZ: a dead simple design (but direct from Nelson Pass himself) which shouldn't have to try too hard to drive the Active Crossover;
4. Re-make my NS10 dual rail clone with nice parts including some Jfets and lots of care
5. The Pumpkin - I have NONE of the active parts for this amplifier.
6. Jfet-CCS-X-Bosoz: I might be the third person in the world to build one of these, which might be a bad idea :xeye:. I have the jfets for this.
7. Build them all and see which sounds best :eek: .
I have also considered building unbalanced to balanced converters and balanced to balanced converters and popping them into the crossovers if it is deemed worthwhile.
I know this appears to be a huge project, but I am keen to get the Orions to sound as good as possible, and Nelson has advised me that discrete component amplification makes the Orions sound a lot better!
Any suggestions please?
And finally, an acknowledgement to Mr. Nelson Pass, without whose generosity and patience I think I would never be able to think about aiming so high in the DIY home audio game. I think a lot of us would be in a similar situation.
Regards and thanks,
George. |
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| Nelson Pass |
Since you need to consider balanced - unbalanced conversion,
I suggest you consider the Pumpkin currently on this forum, which
is a take-off on the UGS type circuits. This should take care of
your needs for a line stage.
The Orion is a sifficiently good and interesting loudspeaker that
it deserves any improvements that can be made in the
electronics. Linkwitz appears pretty agnostic about "audiophile"
issues in electronics, but then his focus is the speakers. He
isn't averse to using "better" active electronics.
The opamps in the Orion circuits can easily be replaced with
discrete versions, and there may be some opportunities to
simplify the system overall - I'll take another look at it.
:cool: |
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| Zen Mod |
| quote: | Originally posted by GeorgeBoles
Evening All,
............... |
not that I can add much (especially not after Papa's not so as usual compendious post) but I have few thoughts........
for bass section you can build whatever you want,even Babelfish JX , but count on fact that I didn't tried it yet.....so take schematic of it just as rough idea . beta tester man steen is gone fishing lately more than usual , and I just have no time .......
for mid section plain babelfish (balanced input) looks good enough
for tweet sort of mini babelfish (mebbe even with decreased voltage and current) but certainly with disconnected CCS modulation , so you will have plain SE,not Aleph one .
regarding preamps........ my humble opinion is that Pumpkin is best of all mentioned , but in every case with promised shunt regs . in that case you'll have killer package .
you can (as we spoke in other thread) make it with almost every eeny weeny jfets you have , with minor corrections .
it's your choice ,overall and after all :clown:
but....... I'm pretty sure that I'll never go that route ..... multi amp system etc .
I remember once I made something like that for a guy with KHs...... toob preamp,toob xover , sand amp for bass , toob PP triode amps for both squakers and squeeks ;)
even if that was sort of two way active system ,pretty much balanced in overall presentation, I prefer plain all passive approach- one amp for all .
but- seems that your spks are just different animal than good ole KHs......
idea in last moment - make F4 for bass . yo can hardly beat that with any sort of money or with anything different.
:devilr: in that case you really need :Pumpkin:
( who sez that I can't rumble much after Papa ........ :clown: ) |
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| Tosh |
| The Orion plus Pass amplification would be one of my dream systems (besides ESLs). But the Orions I heard (with Hafler amps) seemed 'smeared' by all the up-front op-amps, and I expect replacing them with discreet components would be a dramatic improvement. In fact, this would be the first place I'd start, before looking at better amplification. I look forward to hearing NP's thoughts on how this might be done. |
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| GeorgeBoles |
Dear Nelson,
Many thanks for your rapid and thoughtful responses.
I enjoy my Orion's, and I am glad that you think they are worth persisting with in order to get the best out of them. For a DIY speaker design, the parts are quite expensive, especially for a "first effort".
I had to chuckle when you adroitly characterized Siegfried's "audiophile agnosticism", but everyone would agree that his research and developments have contributed hugely to modern audiophile enjoyment.
| quote: | | The opamps in the Orion circuits can easily be replaced with discrete versions, and there may be some opportunities to simplify the system overall ... |
Are you saying that there could be excessive distortion/noise if all the monolithic op-amps were replaced with discrete DIY versions (especially if the implementation were not perfect); that a "sweet spot" might be found by reducing the engineering perfection* of the crossover; thereby reducing the number of op-amps; and that this may allow the use of a reduced number of more "musical", but higher distortion DIY opamps?**
| quote: | | Since you need to consider balanced - unbalanced conversion, I suggest you consider the Pumpkin currently on this forum |
Are you suggesting that:
1. I run a balanced signal from my pre-amp (say the Pumpkin) to the Orion crossover, convert to unbalanced at the front end of the crossover, and (at the crossover output) convert back to balanced for the final run to the power amps; OR
2. Are you thinking that I have balanced outputs on my CD player/other source, and as such, the signal should be converted to unbalanced within/at the pre-amp (hence the choice of a pre-amp with this capability) before being sent to the Orion crossovers?
3. While we are discussing this, is your initial opinion that there is value to be had in converting the output of the Orion crossover to a balanced signal to feed an Aleph or Aleph-X style power amp?
Whoo, boy. A long letter (quite difficult to draft) which I hope makes sense.
Again, thanks for your input, Nelson. Like Tosh, I am very interested in your input.
Best regards,
George Boles.
* P.S. For those of you who are unfamiliar with the Orion Crossover, it "corrects" all manner of things within the speaker design: time delays, baffle effects, floor effect, the roll-off of the drivers in an open-baffle enclosure - along with the "usual" features of a crossover. To do so requires lots of op-amps - 22 single opamps per channel ... and right there starts the op-amp/discrete/musicality/distortion/feedback debate.)
**I am sure that "Grammar Check" would have highlighted that sentence! |
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| GeorgeBoles |
Thanks to you, Zenmod, for your thoughts.
Pumpkin it is for pre-amp, given your advice and Nelson's blessing.
I have been hoarding up parts quite wisely for a while now, and have got lots of useful bits together. In fact, given that Conrad heatsinks is "only" 2100km away, I can get them quite cheaply ($50AUD for his biggest 15 cm * 35 cm), and because there are HUGE steps in voltage/current relationships between the various amplifier topologies discussed in the Pass Labs threads, transformers are the dearest components, and "hardest to re-use in a different project" that I need to purchase. (12V for A-X 30W, 18V for Aleph 30W, 22V or so for a 56W chip amp - but to use 18V for an A-X, then I would need a HUGE VA rating and be making a humungous amplifier ... you get what I mean.)
Therefore I doubt that I really want to make too many "small amplifiers" as a starting point. I would rather keep everything at normal powers, so I can re-use the transformers. I only have a limited number of relatives to "give" my cast-offs to!
What interests me is your suggestion to remove the Aleph modulation for the tweeter. Will that purify the sound (at the expense of efficiency)? Is it just a matter of disconnection or do I have to re-calculate lots of bits and pieces? (I have to go home and eat now, and I will also need to re-read the Zen articles to work out what to disconnect :eek: .
I have been reading this thread so about two years now (paralysis by analysis), that I had sort of assumed that the Aleph modulation was a part of life!
I didn't think that the F4 would work for me, because the crossover is only a +/- 15 volt thing, the maximum voltage swing is somewhat less than that. The other threads are talking about +/- 30V or more swing to drive the F4 ... or have I got the bull by the tail, which I certainly could have done? :xeye:
Bestest regards,
George. |
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| Magura |
| quote: | Originally posted by GeorgeBoles
What interests me is your suggestion to remove the Aleph modulation for the tweeter. Will that purify the sound (at the expense of efficiency)? Is it just a matter of disconnection or do I have to re-calculate lots of bits and pieces? (I have to go home and eat now, and I will also need to re-read the Zen articles to work out what to disconnect :eek: .
|
The Aleph current source does little good for the highs. I would dare to claim that the only place it has no drawbacks is for the bass.
I have made a bunch of Pass style amps, but have ended up using a regular current source or inductor loads instead.
As for the trafo issue. A 2*18V 1000VA trafo will allow you to build just about any Pass construction with a minimum of modifications.
Magura :) |
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| Zen Mod |
| quote: | Originally posted by GeorgeBoles
.............
I didn't think that the F4 would work for me, because the crossover is only a +/- 15 volt thing, the maximum voltage swing is somewhat less than that. The other threads are talking about +/- 30V or more swing to drive the F4 ... or have I got the bull by the tail, which I certainly could have done? :xeye:
Bestest regards,
George. |
I told you that my brain is sorta in red this days :clown:
but- I think that there is also solution for that issue.........
Magura is right for 2x18/1000 |
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| Nelson Pass |
| quote: | Originally posted by GeorgeBoles
Are you saying that there could be excessive distortion/noise if all the monolithic op-amps were replaced with discrete DIY versions (especially if the implementation were not perfect); that a "sweet spot" might be found by reducing the engineering perfection* of the crossover; thereby reducing the number of op-amps; and that this may allow the use of a reduced number of more "musical", but higher distortion DIY opamps?**
|
No. But my experience is that usually complex filter sets are
often composed of elements which "stand alone" without
reference to other elements, so that there is often quite a
bit more active circuitry than necessary. If you believe in the
perfection of the op amps, then you generally won't mind
running the signal through lots of them. Myself, I am willing
to put up with minor imprecision in filter curves as a trade off
for reducing the number of op amps in the gain path. After all,
the result from the loudspeaker will only be an approximation
anyway.
When I was commissioned to rework the cutterhead electronics
for Mobile Fidelity, I found that the many complex elements
involved with equalization, gain and feedback around the
cutterhead each had its own modular circuit and its own op
amp. I think it had about 11 op amps in the signal path -
although I don't recall very well. It certainly simplified the
task for the original designer.
In any case, I was able to reduce the whole thing to one op
amp and retain the measurements of the original. It was a lot
of work though, because allowance had to be made for the
interaction of many passive networks around the single stage.
:cool: |
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| GRollins |
It's not so much a question of distortion in the conventional sense of THD...after all, with sufficient quantities of feedback, you can achieve vanishingly small amounts of any of the usual distortions.
But therein lies the rub.
Huge amounts of feedback tend to impose their own penalties.
Not to mention the sheer quantity of devices (active and passive) that the signal has to go through. One relatively easy example is the passive devices within the chips; there are few people who would claim that a capacitor made of silicon is equal to a good film or mica cap.
Yes, the music gets through opamps, but it's been processed into McSound.
Better to go discrete when possible.
Grey |
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| GeorgeBoles |
Nelson (and Grey),
What you are saying is roughly what I meant. I had no idea that such a HUGE reduction of op-amps could even be possible - clearly the ideal solution. (As you described, the Orion crossover has essentially one op-amp per function.)
It is still possible to imagine that changing all the opamps for discrete versions (without reducing numbers of opamps) might not produce an improvement worthy of the effort.
| quote: | | When I was commissioned to rework the cutterhead electronics for Mobile Fidelity, ... |
Ahh ... Mobile Fidelity used to be my heroes ... Dark Side of the Moon, Abbey Road, White Album, Beethoven's Ninth - George Solti (the last in particular makes the current CD iteration just pale into boringness) ... whistful sigh ....
Thanks,
George. |
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| Nelson Pass |
I spent some time reviewing the (possibly earlier version of)
electronics for the Orions, and it is clear that you can replace
something like half the gain stages with discrete op amps
and buffers and get the same nominal functions.
There is a potential problem here, though. I am hesitant to
step on his toes, since he sells the circuit information (at a
modest price) Perhaps someone would want to work on this
aspect - negotiating permission to proceed with such a project.
:cool: |
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| Tosh |
| quote: | Originally posted by Nelson Pass
I am hesitant to step on his toes, since he sells the circuit information (at a modest price) Perhaps someone would want to work on this aspect - negotiating permission to proceed with such a project. |
SL will be here in London on Nov 13 for an AES lecture. Perhaps somebody can bring up this topic with him. (Maybe myself with some encouragement?) I would love to build a simplified (AND discrete) version of Orion (or Pluto). What would such a 'negotiation' entail? |
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| Tosh |
| Today's the big day when Linkwitz is in (London) town. Anyone have any clever ideas on how to raise the subject with him? Otherwise I'll just fumble my way through, mentioning that two or three members in these forums are anticipating a discrete version of his electronics. (And, ahem, would he be so kind as to redesign them for us...?) |
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| paulb |
I think there would be more than 2 or 3. I make it 3 or 4.
I believe Nelson was offering to do some of the redesign, he was just want SL's permission to proceed. |
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| Tosh |
| Perhaps it needs more than just permission, as I could imagine some actual collaboration with SL being very helpful in seeing this through. I suppose I should just start off with asking what SL thinks about NP having a proper go at it for DIY use and see where the conversation goes? |
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| GRollins |
I believe you're reading a bit more into Nelson's post than he intended. Surely one of you guys is up to putting together an opamp, yes? Once you get that far, just put it in a DO-loop and repeat until the circuit is done.
Go get Nelson's paper on opamps and have at it.
Grey |
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| apassgear |
George,
As much as has been said on the amp topic I would be hesitant to mix gain and no gain amps (F4) on a multiamp system. You will need to pad down (pots on the active xover?) the gain amps to drive the speakers.
This only means that the gain amps will be driven near ground level voltages which to my understanding is a no,no. Or I'm wrong? |
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| GRollins |
So build a crossover with gain...problem solved.
Grey |
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| apassgear |
| quote: | Originally posted by GRollins
So build a crossover with gain...problem solved.
Grey |
Yes, add another opamp? :D
Who needs then a nice line amp like the :Pumpkin: to drive a bunch of opamps? :D
Gee guys, seriouly something isn't sounding good here...:whazzat: :usd: :spin: :scratch2: |
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| GRollins |
If you're going to build an active crossover, you're going to need isolation between stages, something you can tie a feedback loop around, something to offset insertion losses, and potentially add gain. This isn't all that difficult, conceptually. There have been numerous attempts at discrete opamps here, some more successful than others. You can swipe an existing design from another thread if you don't want to design your own. Better yet, steal the opamp out of Nelson's opamp paper and you're done.
Them what thinks chip opamps are the ticket can flip through a catalog and order in anything they want. I'd suggest something with a JFET input, though.
These days I'm going no gain and no feedback in my mid/upper active crossovers. Complementary JFET followers, self-biasing, used as buffers between filter sections. Works like a charm. You'll lose a smidgen of gain due to followers being less than unity gain and a bit to insertion loss, but it's about as pure and simple as you could ask for. It helps that I'm using first order crossovers for the mids and tweeters. You can cascade first order slopes to make a higher order slope, but it starts getting unwieldy; easier to go ahead and do a single discrete opamp and get it over with.
Grey |
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| Tosh |
I asked Siegfried Linkwitz at tonight's lecture, and he has no problem with anybody making any changes or redesigns to the Orion ASP (analog signal processor), as long as it isn't being referred to as 'Orion.' (Would it be stupid to call it diyAurion?)
He also pointed out that his Pluto system (with sub) comes quite close in performance to the Orion, although with slightly shallower soundstage depth (but wider 'sweet spot'). That makes me think Pluto might be the place to start when it comes to bang for the DIY buck. |
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| rlim |
I would be interested in finding out how the number of gain stages can be reduced. For one, the opamps in unity feedback can be simplified to, say, a follower stage. But that's not exactly reducing the number of gain stages. Perhaps Mr. Pass can shed some light here.
Take SL's functional block diagram of the Orions' ASP as a conceptual study. Things that you see being repeated are the all-pass filter, 24db/oct HP, and 24db/oct LP. From a circuit standpoint, how would you reduce the 2-opamp 24db/oct filter to just one gain stage and still achieve the same response. This would be an interesting exercise, and for discussion purposes, we can just draw the traditional cascaded 12db 2nd-order filter w/2 opamps (low-pass, high-pass doesn't really matter), and see how it gets morphed into a single gain stage. I seem to recall that 3rd order filters can be done with just one gain stage. Just not sure about 4-th order without getting into insertion loss and possibly other issues related to gain and phase. |
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| JSprague |
| Tosh should have naming rights, since it was he who confronted Sig. Bit... How about O'Brian (simplified circutry)ASP. Don't want anyone taking all this too seriously |
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| GRollins |
I confess that just looking at the "Orion ASP Function block diagram" gives me a case of the heebie-jeebies. So many opamps--and chip opamps, at that--must sum to several hundred transistors...just in the crossover. All told, there's probably a cumulative hundred thousand dB of negative feedback in there. Yikes! That's the very antithesis of the minimalist school of thought.
Yes, I realize that he's got a reason for all the various bits and pieces, but still...I can't help but think that maybe it would be better to mechanically offset the mid/tweeter drivers than to add yet more opamps to an already overly busy circuit.
Just me being silly again. You guys go on with your project.
Grey |
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| paulb |
For Grey's benefit:| quote: | Originally posted by Nelson Pass
...The Orion is a sifficiently good and interesting loudspeaker that it deserves any improvements that can be made in the electronics. Linkwitz appears pretty agnostic about "audiophile" issues in electronics, but then his focus is the speakers. He isn't averse to using "better" active electronics. The opamps in the Orion circuits can easily be replaced with discrete versions, and there may be some opportunities to simplify the system overall - I'll take another look at it. |
| quote: | Originally posted by Nelson Pass
I spent some time reviewing the (possibly earlier version of) electronics for the Orions, and it is clear that you can replace
something like half the gain stages with discrete op amps and buffers and get the same nominal functions. |
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| SY |
C'mon guys, get serious. This should be done either in the digital domain or with tubes.
Opamps. Sheesh. :devilr: |
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| GRollins |
Paul,
I've seen what Nelson said, but I find Linkwitz's attitude strange--he goes to extraordinary lengths to attend to the most minute details in speakers--while compromising all the things he gains by using circuitry that sets his speakers back to the Stone Age. It just strikes me as odd. You would think that if he were that serious about the sound, he'd choose a better approach to all this eq/time domain/shelving/whatnot.
Grey |
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| apassgear |
| quote: | Originally posted by SY
C'mon guys, get serious. This should be done either in the digital domain or with tubes.
Opamps. Sheesh. :devilr: |
Or start a new speaker project... :hot: |
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| Raka |
| I find this conversation specially interesting, as I'm about to re-think the active filter of my dipole speakers, which are similar to Orion. But before that I have to measure again the drivers, so I have time to study what the alternative could be, alla Pass |
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| Nelson Pass |
This whole thing goes back to the project I did with Mobile
Fidelity back in the early 90's. The cutterhead drive system
had a massive amount of electronics in the signal path for
the purpose of gain, equalization, and feedback. The op amps
dated back to the 60's and early 70's, and there was an
isolated piece of electronics for every function, much like SL's
modular circuits. The advantage of this of course is that you can
play around with these in isolation from each other. The
disadvantage is that you end up running the signal through a
lot of op amps - in the case of the cutterhead system, maybe 10
or so.
What I did with Mofi was to integrate all these things around
a single op amp, the LT1028. To be sure, all the values of
every part were dependent on the others, and it was not a
trivial task, but I was able to accurately reproduce the response
curves of the original circuits.
We would look to do the same with the response of SL's Orion
circuitry with fewer discrete stages.
:cool: |
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| GRollins |
Lacking a detailed schematic I can only make educated guesses about what he's doing in the circuit, but it seems that he's using electronics to do things that I would attend to in the physical design of the speaker. His background is in electronics; I'd lay odds that he's not particularly adept at woodworking and seeks to overcome that electronically.
Grey |
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| rlim |
Nelson,
Would it be possible to show us what you did with the Mofi 1-opamp circuit? It would help to generate some ideas here. I am not creative enough to figure out how one can combine the response of say an LR4 low-pass with an LR4 high-pass into a single opamp, or combining a notch filter with an all-pass. Hmm, maybe this in itself can be an article that you can post at your website? :rolleyes:
Thanks. |
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| GRollins |
He's got a stage in there to roll it off at 140kHz? Okay, that one can go.
Jeez, he uses chip amps for his speakers and recommends anything from Doug Self to Rowland for customers. I guess if you put a signal in and one comes out, he's happy. Somehow, I had the impression that he was more performance oriented. It appears I was wrong. To be honest, the more I learn about his views the more I find myself wondering about the speakers.
Grey |
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| Raka |
Grollins, so I now know that you haven't heard the Orions yet. Me neither, but my speakers are similars to his, with cheaper mids, and I have to say that are excelent to my ears.
Let's focus on the electronics, as I'm sure that there are a lot of people listening to this thread, really excited with the possibility of improving an already really good sound. I would be really happy if I manage to change my filter to a better one. That would be great.
What would you choose instead of the gain module in the ASP?
The active filter of the JohnK dipoles has less active stages, and he's always trying to save on that (placing the poles in the right place, for instance) |
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| eLarson |
| I think Mr. Linkwitz is of the "speakers-matter-most" school. |
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| GRollins |
| quote: | Originally posted by Raka
Let's focus on the electronics...
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Precisely. You'll note that I have not said one word about his choice of drivers or cabinet design.
Let me put it this way...if you heard people exclaiming about the steak at a particular restaurant you might become interested. As a red meat sort of fellow myself, I know I would. Now, let's say that before actually eating at this restaurant, you peeked into the kitchen and saw frozen chicken nuggets being microwaved, instant coffee instead of ground beans, and dried soup mix. These things are not necessarily inappropriate for a chain fast food restaurant, but this particular restaurant is being portrayed as an upper class dining establishment. Hmmm... Does it necessarily mean that the steak isn't up to snuff? No. Perhaps the restaurant has a particular cook who handles nothing but steaks; who goes to the local butcher every morning and hand selects each steak that he will be cooking that evening; who then spritzes a light dusting of herbs and spices over each steak so that it enjoys an entire afternoon absorbing flavor; who then grills each steak to perfection; who then bastes each side with a last minute addition of garlic butter before allowing it to be served.
Perhaps.
But I think you'll admit that it's not bloody likely, given the way the rest of the kitchen is run.
Now, as for my suggestion to dump the 140kHz "RF filter," there's a curious blindness that afflicts many audiophiles in that they look at each component in isolation. If they do consider interactions, it's usually along the lines of "will component X drive component Y?" But there are other things to ponder.
Consider the lowly filter. If someone tells you that there's a 140kHz low pass filter in a piece of equipment, your thought process is likely to be something along the lines of "140kHz is seven times the 20kHz upper limit of human hearing, so that's okay...in fact, that's more than okay...I'll never hear it."
I'll approach this from two directions:
--140kHz isn't 'seven times the upper limit of human hearing,' it's less than three octaves above the upper limit of human hearing. By comparison, compare 20Hz to 140Hz. Suddenly it doesn't seem quite as far away. Given that many instruments (e.g. brass, percussion, piano, synthesizer) have harmonics that go well above 100kHz, this begins to get a little scary. Can you hear 100kHz? No, not as a discrete tone, but it matters in terms of getting the waveform right down below the nominal 20kHz limit (which is pretty arbitrary, anyway).
--My second point--and here I come back to something I alluded to above--is that you're not listening to Linkwitz's crossover in isolation. You're listening to it with a source, possibly a phono stage, a line stage, the crossover itself, and an amplifier...all in series. Now suppose each of those components rolled off somewhere in the 100-150kHz region. In that sense, they're all filters. People don't look at what happens in the passband of a filter. They think that 140kHz is some sort of absolute. It's not. It's the -3dB point. But if you take a moment to look at a normalized filter response, you'll see that it has an effect for a couple of octaves below the nominal -3dB point. Okay, so what's a tenth of a dB between friends? Who cares? Consider what happens when you cascade each of the pieces listed above, each adding a tenth or two to the total. What happened at 20kHz? It's not at all uncommon to see response at 20kHz down by as much as a dB or even two (You'd be surprised how many circuits only make it to, say, 50 or 80kHz, instead of 100kHz; I was being generous when I said 100-150kHz.)
I can't speak for everyone, but I don't much like the idea of having my top end response lopped off before the signal even gets to the speaker.
I repeat--dump the 140kHz RF filter. Go away. Gone. Bye-bye. The easiest way to begin improving this crossover is to remove the unnecessary parts and the ones that harm the signal. Only then can you begin blending the rest into something more reasonable.
What would I choose instead of chip opamps? That's an easy one: Discrete. For that matter, I've already said so at least two or three times above. So now I've said it again.
Grey |
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| Tosh |
Mmmm, steak.....
Nice to have you onboard and working on the same discrete recipe, Grey!
SL doesn't read these forums, but said if we needed to communicate with him we could do so in the Orion users' forum.
Linkwitz is concerned with the basics: getting the loudspeaker to have a uniform polar response. (See his recent lecture here) |
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| Nelson Pass |
| quote: | Originally posted by Tosh
Linkwitz is concerned with the basics: getting the loudspeaker to have a uniform polar response. (See his recent lecture here) |
That's an interesting piece, much of it agreeing with my own
experience, although I don't think it addressed one of the most
interesting issues - the differences in polar response of a dipole
versus a small source. The ideal dipole has no lateral response
(90 deg off axis), and of course the small source does. What they
have in common is little or no diffraction off enclosure boundaries.
:cool: |
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| GRollins |
Being the owner of Magneplanars, I suppose I fit handily into the dipole category, even if they follow a slightly different approach from other dipoles.
I don't think there's much question that speakers are one of the weaker links in the chain, but that can become a problem if someone chooses to take that as meaning that the source and electronics aren't important. At which point you've thrown out the bath water, the baby, the towel, and for good measure, the bar of soap. Whether Linkwitz fits into that category I'm not sure, but it's certainly not impossible.
Don't misunderstand--the idea of open baffle speakers is good. If you use good drivers you can come up with excellent results. I'm just a little concerned about his apparent lack of interest in anything else in the system. If, for instance, we assume that he used chip amps to voice the speaker, there might be...issues, shall we say, when it's hooked up to other electronics.
If I get a chance, I'll look into the lecture thing and come back later tonight. (My fingers are crossed that it's a light night...)
Grey |
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| KSTR |
Grey,
regarding the HF filter, I suppose it's just kind of a safety issue, because in a typical HiFi environment you can't be sure that there is not a siginificant amount of HF around, given unperfectly shielded devices, unshielded cables used by some people and so on. AM-broadcast stations nearby, cell phone (TDMA) poison, SMPS in all sorts of other equipment... btw, do you know the extremely severe HF/EMC test conditions for mic preamps and other studio gear to be used in german broadcast etc? Not a single unit will ever pass anything above 70kHz if it aims to get the approvals.
So IF you know your system is free of HF, dispose of the filter. If not, better to loose a dB or so at 20kHz (we should consider phase also, more precisely L/R phase match) than to hear Radio Eriwan in the background... and, last not least, SL is a seasoned RF engineer -- look at the list of RF analysers he has (co-)designed while at HP.
I onced listened to the Orion and they blew away, even with "that dreaded op-amp" XO and a cheap AVR for power amplifier duties.
One could think of many ways of improving the electronics, successively. Install the best available op-amps (say, National's LME series or one of the TI THS types... or even discrete JE-990's or so), maybe bias them to class A, improve the power supply, make the shelving filter passive. If one doesn't want feedback of any sort one must go for passive LRC filters which then require low impedances to be doable (uhm, them coils), the phase shifters could be done with xformers (or align the speakers better)....
- Klaus |
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| GRollins |
I found that transcript to be interesting, both for what it said, and for what it did not say. There were lots of pretty graphs and things, but honestly, I didn't see anything groundbreaking. The points he made are at least twenty years old and quite possibly older.
Some specific points:
--It is implied, if not stated outright, in the transcript next to Slide 8, that the photo is of his listening room. I have two quick comments. One is that the room, while an interior decorator's dream, has vast expanses of glass. Sorry. Beautiful it may be, but that's not a good listening room. I'm sure that Linkwitz's response would be something to the effect that the speakers are far enough away from the glass that the reflected sound is ignored by the listener's ear. But he, himself, admits that the room is hard, in the acoustical sense, with a long reverberation time. He rationalizes this by saying that reverberation times are not important for small acoustical spaces. I vehemently disagree, but will leave it at that. My other observation is that he is clearly breaking his own dictum to have a symmetrical listening room.
--I agree with his stated guidelines, but not necessarily for the same reasons he advances:
1) Symmetrical listening space (even if he breaks his own rule). I went so far as to move a door in my listening room during rebuilding so as to make it match one on the other side of the room. Why not? I already had all the pry bars, hammers, etc. out...might as well take an hour or two and reframe the silly thing. Besides, they'd done a lousy job of hanging the door the first time. By the time I got done with it, it hung perfectly. But I digress...
2) Delay reflections by at least 6mS. Honestly, more is better, but I won't quibble.
3) Off-axis sound (and by implication, the reflected sound) should approximate on-axis sound.
This is all pretty much old news, which isn't to say that it isn't important or correct, just that I'm not sure how timely his revelation is in the overall scheme of things.
--He repeats several times how similar the two speaker systems sound. As a matter of fact, it's the entire foundation on which his presentation rests. There are any number of possible conclusions that could be drawn. One is that he designed both speakers, so it's no surprise that they should sound similar. Assuming that he has a fairly clear idea of what he wants in a speaker, he's going to keep fiddling with it until it sounds the way he thinks it should sound. If he can't get the sound he wants, he will presumably try different drivers/cabinet configurations/crossovers/etc. until he succeeds in getting something that sounds "right" to him.
To use a commercial example, all B&W speakers have an identifiable house sound. From the largest to the smallest, they are all cut from the same sonic cloth. If you like the B&W sound, you'll like all their speakers to greater or lesser degrees. If you don't, avoid them like the plague, because you will not find anything in their lineup that will satisfy you.
--Several of his conclusions are, at the minimum, open to question. He states that imaging is dependent on the three things listed above. Fair enough. But all it takes is one counter-example to burst the bubble, and I have just the pin.
Behold, the Rogers LS3/5a.
The original mini-monitor. The one that started the entire orchestra-in-a-box, sub/sat phenomenon. I still have mine and I still listen to them sometimes. They have obvious flaws; the bass is uneven (on purpose) and they flatten dynamics something fierce (a particularly complex crossover sporting [ugh] iron core inductors), but they are justly famous because they are true to the essence of the music and they image like a bat out of hell. Believe it or not, there was a time when there weren't any mini-monitors. With the advent (ahem) of the acoustic suspension woofer, speakers began to get smaller (and less efficient--something the LS3/5a took to extremes), but to build a speaker less than the size of a shoe box and have so much music come out of it was a near miracle.
So what's my point?
Well, you see, the LS3/5a is a quirky little thing. Pull the front grill and you'll see a KEF B-110 mid/woofer and a modified KEF T-27 tweeter. But then you notice something odd...thick felt surrounding the tweeter. That felt is close to the dome. Very close. As close as the exposed leads of the T-27 will allow. And it's so thick (on the order of 3/4") that it reaches from the front of the speaker to the speaker grill. That's on purpose. The felt is there to absorb any high frequency information that tries to go across the face of the speaker to re-radiate from the front corners, which are quite square, thank you very much (this being long before rounded corners came into vogue). Now, one of the things about this felt is that it enforces a pretty strict radiation pattern on the tweeter--it is an unapologetic point source. But note that it's not an omni-directional point source, it's a uni-directional point source. Closer to a laser than a candle flame in radiation pattern. And that, right there, is the counter-claim. The LS-3/5a's woofer is not so-treated, and can be considered omni-directional, at least in the lower frequencies (crossover ca. 3kHz if I remember correctly), but that tweeter...that tweeter is different...and in doing so it lays waste to Linkwitz's idea that the off-axis sound should be a close approximation of the on-axis sound for good imaging, because the LS3/5a was anything but similar in off-axis response.
So is Linkwitz wrong? Well, yes...and no. In that he indicates that the only (or perhaps the best) way to achieve good imaging is to obey his three principles, he is wrong, clearly. You only need one good counter-example to prove a point. But that even off-axis response is a good thing, even if not necessarily for imaging--now that I can agree with. It brings fuller, richer sound to the table. But not necessarily better imaging.
Indeed, one of the more bizarre speakers ever to hit the market, the Walsh, and its spiritual descendants, the Ohm speakers, are omni-directional to a fault. They image widely, and I mean wiiiidely but with next to no image depth. The effect is not unlike that spaced-out image you get if your speakers are out of phase. But this only serves to emphasize that a uniform off-axis response does not of necessity give you a good image.
...Just in case you didn't consider the bubble sufficiently burst before, that is...
--One thing that I don't feel that he addressed particularly clearly is the reduction in side-radiated acoustic energy from dipolar speakers. Perhaps he didn't emphasize it because it ran counter to his thesis. I believe I saw where he noted that the dipole had a deeper image, but he took it no further. Suffice it to say that if there's less sound hitting the wall, then there's less sound to reflect to your ear and confuse the image.
Particularly in a room with twenty-seven acres of highly reflective glass.
--I also have to wonder if his impressions of a flat speaker having too much high frequency energy were also influenced by that room. No, I'm not necessarily arguing that his essential point is wrong--others have reached similar conclusions--but that he might have gone further than necessary. As evidence, notice the distinctly lowered upper high end in his graphs. A bit overdone, perhaps?
--Finally, I'd like to advance the possibility that the reason that he feels that the two speakers sound the same is that he has a terrible listening room, literally awash in reverberant sound. 450 mS by his own measurements. That's enough reverberation for a largish jazz club or a small church. With that much reflected sound zinging about, it would be difficult to tell an aardvark from a zebra. Yes, he says that others reached the same conclusion about the speakers that he did--but in that same room. I have to wonder if the same conclusion would be reached in a better listening room.
I won't insist on these last two points...just something to think about.
Grey |
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| GRollins |
| quote: | Originally posted by KSTR
Grey,
...regarding the HF filter, I suppose it's just kind of a safety issue...
... and, last not least, SL is a seasoned RF engineer -- look at the list of RF analysers he has (co-)designed while at HP.
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Indeed, and a safety issue that any number of other pieces of equipment have managed to do without. If you think it's cool, leave it in. Won't bother me a bit.
As for Linkwitz and his design credentials, I have degrees in geology and psychology, I'm a pretty good bass player, a whiz with bees, and I brew excellent beer. None of which are in any way relevant to my abilities--or lack thereof--in the audio field. They're separate and distinct. At best, I may drag them in when making an analogy but that's about the extent of it. Linkwitz's RF designs do not necessarily make him a good AF designer, any more than my ability to cook gourmet-level steaks means that I'm a crackerjack asparagus cook (trust me...I run from asparagus...wouldn't have a clue how to cook it).
I am saddened--but hardly surprised--to hear that German radio stations bandwidth-limit. Stations here in the US are no better. Of course, it's been eons since serious audiophiles cared to use FM broadcasts for source material.
In all fairness, I will muster a lukewarm defense for the Public Radio folks. They at least let some low end through. On some of their stations. From where I am I can get acceptable signals from three different PBS stations...and none of the three sound the same, despite broadcasting the same program material. But even the worst of the three sounds better than the best of the other local stations.
Grey |
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| Raka |
Grollins, good example that one of the restaurant, and I agree. Let me put another one:
"Look at this guy, he's just made a car using a lot of hours just on it's shape, he says it's the main point of a racing car. Oh my, he just throw the first motor he got on ebay!. I know how to make motors, and for sure I know of aerodynamics. I'll try his car with the motors I make, maybe we got something there for a Christmas present." |
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| SY |
| quote: | | Linkwitz's RF designs do not necessarily make him a good AF designer, any more than my ability to cook gourmet-level steaks means that I'm a crackerjack asparagus cook (trust me...I run from asparagus...wouldn't have a clue how to cook it). |
My speakers don't seem to use Rollins crossovers.
BTW, public service message: just trim off the bottoms from the asparagus, toss them with some olive oil, salt, pepper, garlic, and a touch of balsamico, and throw them on the grill. Cook, rolling them around occasionally, until they're done. |
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| GRollins |
| quote: | Originally posted by SY
My speakers don't seem to use Rollins crossovers.
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I have a love/hate with any filtering system, be it RIAA or crossover (passive or active). I find them perversely fascinating, but frustrating to work with. Every time I finish one, I swear that I'll never do another filter. Six months later, I find myself scratching out a new schematic on a piece of scrap paper. Oh, well.
Grey |
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| Variac |
Well, Linkwitz certainly understands filter systems, which is why his experience is more relevant that if his expertise was how to cook a steak.
I find the comments about his listening room interesting and fun, but to comment negatively about any speaker design that has such a good reputation without listening to it is kinda silly- especially when it is different than most others.
His ideas WERE more radical back in the day of the Audio Artistry Beethoven speaker, which had a great reputation -when open baffles were rare. I think a lot of the current open baffle interest is due to the AA speakers..
Clearly the guy is doing many things right, but when you are a groundbreaker, eventually the world will catch up to you. In fact though, few speaker makers use his circuit intensive approach even today. Why? well we can find out. I think that is the point of this thread- Can the Linkwitz circuitry be kept intact, using less components and discrete components, yet still be true to the Linkwitz approach? If a bunch of opamps can be eliminated while still performing the same exact functions, I think that that would be interesting to hear - how much better would it sound?
The idea would be to be able to compare the two I would think. Another idea is to modify the circuitry itself to be "better" , but that's anothe project.
My son thinks that Jimi Hendrix isn't that radical, because lots of people play like him now..... |
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| GRollins |
At what point does it cease to be an Orion?
This is not just philosophical musing. If, for instance, someone were to take my earlier suggestion and use a physical offset to time align the drivers rather than do it electronically, would that still be an Orion?
If the intent is to re-imagine Linkwitz's speaker, it would be useful to set some ground rules as to what does and does not constitute fair play. I suppose it's clear that I'd go back nearly to square one, others seem to feel that a simple opamp swap is the limit.
No, there's no reason that people can't do various levels of modification, according to their level of experience and ambition, but then the thread will get badly fragmented, with some going for a full rehabilitation of the crossover, others swapping opamps, some opting for a physical rebuild. To keep it coherent, I'd suggest laying out a clear program, just to keep things organized.
Also, just out of curiosity, how many people out there actually own one of the Linkwitz designs? And of those, how many are seriously interested in modifying their speakers?
Grey |
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| threefff |
Hi Grey,
me, for instance. I own a pair of Orions and I am just about to reproduce the XOs in the digital domain (oh, how shocking, my dear).
I would be very keen on comparing the original, the digital, and the "passed" XOs. Unfortunately, too stupid to do the latter on my own.
Cheers,
Thomas |
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| Davey |
Folks,
I think "the line" with SL is very clear. And he notes this in the "caution" at the bottom of his front page.
http://www.linkwitzlab.com/#CAUTION:
Any of the design modifications being discussed here would cause the Orion to cease being an Orion....in SL's view.
However, I think he enjoys/welcomes new thinking on any of his efforts. But you better have your A-game ready if you find yourself in a discussion with him about it.
SL does not participate in most discussion forums....which I guess kind of makes him an easy target, but you might find him at the OUG from time to time.
Here's an example of recent "modification" to one of his designs and the discussion that ensued.
http://orion.quicksytes.com/viewtopic.php?f=12&t=784
Cheers,
Dave. |
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| paulb |
I'm interested in the Orion because I am getting ready for a speaker upgrade, and it seems like a good choice: It seems to be a credible, accepted design. Lacking carpentry ability (and inclination), I need something simple that I can talk somebody into helping me build. I like the idea of the open baffle. And finally, I am a firm believer that biamping/triamping is the way to go, and there aren't very many DIY designs out there employing it.
My interest in this thread is because I would like to use a different version of the electronics for the Orion. Also, I need an excuse to keep building amps. I'm not particularly interested in just stuffing the Linkwitz board and knocking off a few gainclones. I would like to see it with simpler but high-end DIY electronics. I may end up using a DSP-based system to tinker around with it a bit, but in the meantime it would be nice to build something where I am reasonably confident of the results. |
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| Pasi P |
Hi all,
I think it is ok, if anybody tries to improve Orion desing.
But. Anybody who is saying Orion is from stone age etc. should first "sit back and listen" properly built Orions with electronics Linkwitz recommends.
If one is not like what he hear, then it is OK to say what he think is reason to bad sound.
OP amps could be bad somewhere in poorly designed system, but Orion loves op-amps IMHO ;) |
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| Variac |
| quote: |
If, for instance, someone were to take my earlier suggestion and use a physical offset to time align the drivers rather than do it electronically, would that still be an Orion?
If the intent is to re-imagine Linkwitz's speaker, it would be useful to set some ground rules as to what does and does not constitute fair play. I suppose it's clear that I'd go back nearly to square one, others seem to feel that a simple opamp swap is the limit. |
First, I'm pretty sure that offsetting the drivers is something that would occur to Linkwitz and he rejected that. As I pointed out, he had a manufacturer making his (quite expensive) speakers in the past- he isn't some guy that just made some speakers for himself in his living room. I don't think that he would be concerned with their possible lack of woodworking skills!
Offsetting the drivers is like just about everything, a compromise, as if you offset the drivers you can end up with baffle diffraction problems, if you slope the baffle, then the response changes depending on how close you sit, etc. So I think that that choice is a fundamental SL choice and shouldn't be tampered with.
I think that the scope of the project is pretty clear:
This project is to leave the Orion panel and drivers alone, and confine any modifications to the circuitry. This would involve substituting discrete opamps for chip opamps, and combining circuits
as is possible to avoid redundancy and eliminate maybe half the opamps. Of course something like leaving off the high filter would be something that could also be easily explored...
With this definition, the project could be useful to any of the owners of an Orion, and actually encourage more people to build them, which I assume would make Siegfried Linkwitz more interested.
Also it would allow an easy comparison between the stock crossovers, and the new crossovers, which is one of the major appeals of this proposed project
Unfortunately , this combining of circuits involves "The Art of Electronics" to coin a phrease ;) , and will require someone of a certain level of expertise....
Also, It appears that the only way to get the current exact circuit is to have a set of his boards, which some people here have. I believe that he sells unpopulated boards. Perhaps someone with the boards can compare them to the circuit I linked to. Is it true that there isn't an exact schematic of the current circuitry
available? |
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| Variac |
the name should have ASP in it as that is what we are replacing it we agree to only focus on the "black box" Aurion is a little too close sounding to Orion so I think that might cause confusion. Nice of Linkwitz to offer a final tribute to the disappearing planet Pluto...
How about something like the "Mercury ASP" or as Homer S. would like: "Uranus ASP" |
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| eLarson |
So Orion was the lover of Artemis. She also killed him. (oops.)
Scorpio was what Orion was chasing after that led to him being shot by Artemis.
Apollo was the one who sent Orion on the trail of the scorpion, and also the one that shined the beam of light on Orion far away at sea. And he was the one that challenged Artemis to hit the little spot of light with one of her arrows.
The Apollo ASP? The Artemis ASP?
Of course then there are the various stars in Orion--most famously Betelgeuse, but also Bellatrix, Rigel and Saiph; Mintaka, Almintaka and Anilam make up the belt. (It's been some years since Astronomy class, my apologies for any misspellings.)
eL |
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| Malotron |
I saw a SF film from 1978 called "Capricorn One" last night. A bit like Apollo 13 meets All the president’s men. Not a bad film. I see Its Title ( minus the nefarious subplot ) as a Procrustean fit: a (science) project diverted from it’s intended aim and it’s also a star constellation.
So... Capricorn ASP? :) |
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| GRollins |
| quote: | Originally posted by Variac
Offsetting the drivers is like just about everything, a compromise, as if you offset the drivers you can end up with baffle diffraction problems...
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This is why they invented felt and foam. Felt is better over the long haul. The problem with most speakers is that they cheap out and use too little thickness. It takes something on the order of a quarter wavelength thickness to achieve decent attenuation. Time, time, and again, I see felt that is, at most, a sixteenth of an inch...an eighth of an inch thick at best. Yeah, right, guys...care to try again?
As for offsetting the baffle occurring to him--don't bet on it. If he thinks that an electronic solution is satisfactory, then it may never have crossed his mind. If there's one thing I've learned over the years, it's that if someone already has a solution in mind, they are resistant to trying any other possibility that may come up. You see it everywhere, Washington D.C., the Middle East, at work, in marriages, you name it.
You can't have it both ways, either the guy is a genius at filters...in which case it's a big duh that he's going to approach this as a filtering problem that has an electronic solution as opposed to a mechanical one, or he's not...in which case the whole crossover is open to redesign (and possibly even the mechanical design of the speaker itself). So which is it? Make your choice and place your bets, folks.
The blind assumption that someone has evaluated all the options and chosen the best is antithetical to the basic philosophy of DIY.
If the idea is to keep everything as similar to the original Orion as possible, then you're limited to two options: Try different chip opamps or build discrete opamps.
There. Project planning done. Gentlemen, start your soldering irons.
Grey |
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| Variac |
Grey, I agree that it is very likely that Linkwitz has a bias towards using fiters instead of other solutions, and that is what makes it an Orion IMHO. This project was started by a guy that likes his Orions but wants to go further.
You know well that I was making a point that every solution has its good and bad points including offset. In my limited experience, I would be tempted to approach the problem as you suggested, but I suspect the final speaker designed by me would be not as good as the current Orion, and would not be in the spirit of the Orion.
Clearly, as originally defined, the solution should be similar to one of your statements. The idea is to make everything as similar to the original Orion as possible except for the ASP, THEN we can answer the question which I feel is the "philosophical " one here: Will the sound of the speaker- already acknowleged by many as being quite good, be improved by:
1. discrete components
Or
2. better opamps
3. Strangely you didn't mention this one and I think it is the most powerful: Eliminating some opamps by artful manipulation.
I think 1 and 3 are of the most interest to people here and I think that only you seem to find this bothersome. There is also a practical matter here. The owner of Orions would find it very easy to compare the original ASP to the modified ASP, Whereas if the physical speaker panel is changed, then comparisons are going to be difficult, as is the possibility of most people here contributing to the design as it appears that many people here don't even own the speakers let alone have listened to them..
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| Variac |
| Nelson, don't you sometimes use a passive network before a power amp, and would that be one of the approaches here? |
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| S.A.G. |
Variac,
Given the large quantity of OpAmp involved, point number three above is where I would focus most of the efforts here. The M.O.J. Hawksford paper referenced before could be one viable alternative.
Also, using some passive filtering could be a viable solution as it should trade some S/N ratio for better distortion figures.
SL himself provides some guidelines for passive, line level filtering:
http://www.linkwitzlab.com/proto.htm
Regards
Giorgio |
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| Nicke |
| quote: | Originally posted by GRollins
If there's one thing I've learned over the years, it's that if someone already has a solution in mind, they are resistant to trying any other possibility that may come up. You see it everywhere, Washington D.C., the Middle East, at work, in marriages, you name it.
Grey |
Grey, that is the exactly what you are doing, you judge the design without having heard it just because of the choices SL made with the physical design and the ASP.
The Orion(I have a pair at home) sounds great with the opamps IMHO, but if there could be improvements with the ASP I would like to try them.One easy way would be to replace some of the opamps(around the filter sections) with a couple of JFET buffers, it would not be that difficult to build an adapter with 2 buffers that could be put in the IC socket... |
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| Wingfeather |
Isn't it important to remember that offsetting a driver and introducing a time delay really aren't equivalent? Like, at all? Since the Orion is a dipole speaker it's probably safe to assume off-axis response was one of SL's priorities in its design. Physically offsetting a driver changes the off-axis response in a way that electronic time-delay does not.
No? |
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| Tosh |
First off, the Orion system I heard about two years ago is the best loudspeaker I have ever heard. I listened for several hours with many of my own reference tracks and other difficult passages, sometimes at loud enough volumes for the woofers to hit their stops. The delicacy of the plentiful bass alone is something which must be experienced first hand. These were driven by six Hafler DH-220 (or 200?) amps, but I still think that the lack of ultimate clarity (or liquidity or darkness) behind the treble came from the op-amp maze. (These were not Orion+ which add an additional rear tweeter.) I would still build the Orion system as-is (when I've saved up my pocket money) but would be much more motivated knowing there was a way to get around the op-amps by going discrete (and line-level passive where possible) and using as few transistors as possible. So I agree that the scope of this project should be only to simplify the ASP (and make it usable with balanced?) while leaving the drivers' physical arrangement alone.
Nobody liked the O'Brian/O'Brien idea? (I guffawed out loud!) The name "O'Brien" reminds me of the Seinfeld episode where George pretends to be O'Brien to get them a limo ride from the airport and instead gets everyone in a pickle. The impostor aspect applies for us here also, plus it's just too silly to pass up. Characters from mythology seem too arcane for use here, despite being very applicable. Especially Artemis which seems eerily appropriate as killer of Orion. And "Uranus" will be the perfect name when diyAudio launches a Pluto mission.
So I nominate O'Brien ASP. |
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| GRollins |
| quote: | Originally posted by Variac
3. Strangely you didn't mention this one and I think it is the most powerful: Eliminating some opamps by artful manipulation.
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Actually, I've already suggested same, but people acted as though I'd insulted their grandmother. I'll bow out and let you fellas debate what to change so that nothing is changed [sic]. After all the speaker is perfect, no?
Nicke,
Anything with, what was it? 22 opamps? speaks powerfully that the designer is, shall we say, besotted with one particular approach and is convinced of the strength of his position. You folks are in the paradoxical position of saying that the ASP needs changing, but that the Orion speaker system is the most marvelous thing on the face of the planet.
Uh, sorry, but I missed something. If it's that wonderful, you should leave it alone and be happy.
My impression is that some of you need to get out and hear more speakers. Get a little more experience with what can be done by other speaker designers--without opamps and an entire factory's worth of parts. There's an entire world out speakers out there. Go hear some electrostats: Martin Logan, Quad, or Sound Labs (some of the best soud I ever heard was through a pair of Sound Labs electrostatic speakers--simply gorgeous). Listen to some Magneplanars. Try out some horns. Give some of the better box speakers a shot. No. Really. Somewhere in there, you might discover that a parts farm may look impressive, but it's not the only solution to the various problems that come up during the design phase of building speakers. It may not even be (gasp!) the best answer.
For that matter, at least some of you might even get a kick out of the full-range speakers that Nelson (and others) are spending so much time talking about. Get rid of all the surplus electronics.
Grey
P.S.: Before anyone starts in with the inevitable complaint about the price tag of the speakers I mentioned above, please note that I did not say that you should buy them--I said you should listen to them. Get out. Live a little. Learn what is possible. Should you find, say, that the Martin Logans tickle your fancy, you'll find that it's not difficult to build an electrostat. If, by some chance, you like the Magneplanars, reflect on the fact that I built a planar driver of that sort in a single afternoon.
EDIT: If you're still searching for a name, might I suggest that you're looking at this the wrong way...call it the Cleopatra, who (according to some accounts) died from the bite of an ASP. |
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| Variac |
Geez indeed,Grey, you are the one creating the strawman that everyone here thinks that the speaker panel is perfect. I don't see that in the comments posted- and I personally don't think that's the case. Certainly the fact that Linkwitz designed the Audio Artistry loudspeakers, including the Beethoven model which was rated as an A, fullrange level loudspeaker by Stereophile I believe, implies that he can make a decent sounding loudspeaker. Granting that being blessed by them is not the ultimate criteria...
Instead, its as you said earlier- a philosophical choice that seemed to be made in the first post, in that ORIGINAL basic question is whether all those opamps and chipamps could be replaced or eliminated and would the speaker sound better? I think that probably everyone who posted here feels that it would.
I think that the problem was originally proposed with this angle, and that people feel that it would be a more pure experiment if some variables were left out. I agree that possibly the speaker could sound even better with a stepped baffle instead of some circuitry, but how are you planing to impliment that? Are you going to make the speaker your way? is anyone else? Instead some of us are proposing that a more controlled experiment is to just change SOME parameters and see how big an improvement (i have to say "if any " here to appear unbiased ;) there would be)
There is a practical aspect to this as I have mentioned. A current Orion owner could swap in the new design in minutes and compare the two . Another advantage is that the design could be done possibly more realistically in an online discussion format than a speaker baffle redesign..
On the other hand , I'm not too sure who is able to do this alchemy of artistically combining the components to use less opamps. It seems that the procedure is to try to combine functions, then measure to see if you achieved your goal. Most people here probably don't have the equipment for this..or the knowledge perhaps..
I'm not the promoter or organizer of this project, so any one can do anything that they= want and post it here. Grey, if you want to make a list of changes you would make to the speaker panel and the electronics, I don't think that you will be torn apart or anything, just do it - that would have taken a lot less verbage than complaining that everyone is jumping on you..
This discussion that we must decide on a philosophy came from you I believe..
| quote: | | it would be useful to set some ground rules as to what does and does not constitute fair play. I suppose it's clear that I'd go back nearly to square one, others seem to feel that a simple opamp swap is the limit. |
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| GRollins |
Variac,
Indeed, you have touched on the nub of the thing. From where I sit, this appears to be turning into what I call a "herding cats" thread.
--Person A wants the Orion just the way it is now, but "better" in some unspecified way. Perhaps more discussion would clarify for this person the way to go, or perhaps they're just kinda "lurking" (is that the right word?), albeit with occasional posts.
--Person B thinks chip opamps are just peachy and wants to swap opamps around. (Clearly, I'm the wrong guy for that discussion.)
--Person C wants discrete opamps that will somehow fit into Linkwitz's existing circuit board. (I dunno about that...if the board I saw on his site is the same one they want to put discrete opamps on headers into, I don't think there's enough room.)
--Person D gets the idea that Person C's desire is destined for frustration and wants a completely discrete circuit that preserves all the original functional blocks of Linkwitz's concept. And he wants PCB artwork, too. In fact, every Person from here down is going to need PCB artwork to realize their circuit.
--Person E wants to combine all the original functions into half the number of functional blocks but still using opamps.
--Person F wants the same thing as Person E, but with discrete circuitry.
--Person G sees that there are, perhaps, some things that can be dropped, but wants to keep chip opamps because he has a box full of them.
--Person H wants what G is thinking of, but discrete.
--Person I has a table saw and...
(...and at least six or eight other permutations that I'm not going to take the time to list.)
Get the picture? This is turning into a herding cats thread. That's why I asked for someone to set some boundaries to the problem. As things stand now, Person A isn't really a problem, he just wants to talk about the speaker. Person B isn't really that much of a problem, either, at least not to me...I'm the wrong guy to ask about which opamp is 'hot' this week. But from Person C on, you begin tallying separate projects and the total is going to be something like eight or ten or more related-but-separate R&D projects, with all that implies about time, money, and commitment. No thanks.
And even if you were to set strict boundaries at this point the thread would wither, because the Persons whose desires were not being met would feel cheated. At which point the end result would satisfy perhaps two or three people...maybe.
I used to try to stick with such threads. These days, I tend to back away and let the cats alone.
No harm, no foul. You folks enjoy yourselves.
Grey |
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| Pasi P |
| quote: | Originally posted by GRollins
My impression is that some of you need to get out and hear more speakers. Get a little more experience with what can be done by other speaker designers--
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That is allways good conclusion. We should listen more. Not speakes but music, though ;)
I am pretty sure that everyone who likes Orions are not lived in darkness and listened nothing else.
Btw. Have you listened Orions? |
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| Nelson Pass |
| quote: | Originally posted by Variac
Nelson, don't you sometimes use a passive network before a power amp, and would that be one of the approaches here? |
Yes, and maybe.
We have a pair of Orions (more specifically Wayne does) and
also a supply of SEAS drivers of all sorts. So we have the
materials at hand.
I have enough data to begin consolidating the circuits into a
more compact approximation of SL's circuitry, however it
chews up time, which is my most precious commodity. What I
think I'll do is to tackle it piece by piece.
The other temptation is simply to take the Orions and develop
a crossover set for it from scratch and see what I get.
:cool: |
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| Variac |
Well, since you are the only one that seems to be tackling the issues means that you get to choose the issues that you tackle.
And the speed at which you do your tackling :bawling:
Actually I'm in no hurry- I just think that this is interesting..
It is only my opinion, but I think it would be generally cool to tackle most (but not necessarily all) of the issues that Linkwitz did, just BECAUSE that's his approach and it helps answer the question as to how much better discrete opamps and amps would make it.. Leaving a few off is certainly kosher of course..since you are the tackler...;) |
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| john k... |
| quote: | Originally posted by GRollins
Also, just out of curiosity, how many people out there actually own one of the Linkwitz designs? And of those, how many are seriously interested in modifying their speakers?
Grey |
About a year an 1/2 ago, having designed the NaO speaker system and having been asked many times how the NaO compared to the Orion I took it upon myself to build a pair of Orion speakers based on the info presented on SL's site; i.e, the Orion challenge. However, my approach was to look at SL's posted transfer functions and then set about designing active circuits which emulated the resulting acoustic transfer functions directly, rather than in the piece-wise approach SL used. It was a simple matter to eliminated a number of the opamp stages (6 per channel) by combining and optimizing specific active blocks. |
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| GRollins |
| quote: | Originally posted by Variac
Leaving a few off is certainly kosher of course..since you are the tackler...;)
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Whereas if the tackler were me, a different set of rules would apply...?
Grey
(who is chuckling at this turn of events) |
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| kropf |
Am I correct in surmising that an op-amp must use considerable feedback to simulate an inductor? If so, you must have enough feedback at the highest frequency that the op-amp is expected to be effective. How much feedback is required: 10dB margin, 40dB margin? At what frequency: 2x the filter freq, 10x freq., higher?
The buffers clearly require less open loop gain.
This is one necessary starting point to define the specs required when you begin substituting discrete for IC op-amps.
Jeremy |
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| Nelson Pass |
| quote: | Originally posted by john k...
About a year an 1/2 ago, having designed the NaO speaker system and having been asked many times how the NaO compared to the Orion I took it upon myself to build a pair of Orion speakers based on the info presented on SL's site; i.e, the Orion challenge. However, my approach was to look at SL's posted transfer functions and then set about designing active circuits which emulated the resulting acoustic transfer functions directly, rather than in the piece-wise approach SL used. It was a simple matter to eliminated a number of the opamp stages (6 per channel) by combining and optimizing specific active blocks. |
You are teasing us twice:
First, you don't comment on the quality of the results, and
second, you hint at the possibility of saving us a lot of work.
:cool: |
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| kropf |
Since the block diagram is posted on the web site, it seems to be fair game to try to emulate the general functionality of the Linkwitz ASP. However, in order to build an "Orion," one must purchase the construction plans, with which one presumably gets the crossover frequencies, etc. for the ASP circuit. As a result, this project should never get specific enough to infringe on that information. Any filter component schematics ought only to give equations on how the R's and C's affect the blocks' function and not give actual values for R and C, although suggested ranges may be appropriate (i.e. Cmax = 10 uF, Rmin = 1k, etc.)
Just my 2cents.
Jeremy |
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| Nelson Pass |
| quote: | Originally posted by kropf
However, in order to build an "Orion," one must purchase the construction plans, with which one presumably gets the crossover frequencies, etc. for the ASP circuit. As a result, this project should never get specific enough to infringe on that information. Any filter component schematics ought only to give equations on how the R's and C's affect the blocks' function and not give actual values for R and C, although suggested ranges may be appropriate (i.e. Cmax = 10 uF, Rmin = 1k, etc.)
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Agreed, and a more specific effort should be preceded by a non-
ambiguous statment by SL. That said, those who have paid for
the information from SL would presumably be able to insert
the appropriate values.
:cool: |
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| john k... |
Sorry to teast but as the designer of a completive system I don't think it is rightly my position to post the modifications I made. There is some history here and I don't want to come off as implying that my mods are superior to the original. However I will say that loosing 6 active stages certainly didn't hurt.
Over time I did make some changes to make the system balance to make it more suitable to my taste. I added some warmth in the lower midrange because I though vocals lacked body. But that is not specifically associated to the ASP topology.
At the time I build the system the ASP block diagram and transfer function response posted on SL's site (or the version I have from SL's site) gave sufficient information in terms of the gain of each stage and filter corner frequencies of the HP/LP filters. There is some ambiguity for delays but with these are pretty easy to gleam form response measurements.
I also ultimately purchased the plans set/boards.
The Orion is certainly an excellent speaker but from its inception I have felt it was overly complex in its active circuits. |
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| Eric Weitzman |
| quote: | Tosh wrote:
First off, the Orion system I heard about two years ago is the best loudspeaker I have ever heard. I listened for several hours with many of my own reference tracks and other difficult passages, sometimes at loud enough volumes for the woofers to hit their stops. The delicacy of the plentiful bass alone is something which must be experienced first hand. These were driven by six Hafler DH-220 (or 200?) amps, but I still think that the lack of ultimate clarity (or liquidity or darkness) behind the treble came from the op-amp maze. |
At the time, I was using Hafler T1600 amps. If we bottomed out the woofers, I must have had the Adcom arc welder on them.
| quote: | | These were not Orion+ which add an additional rear tweeter. |
Now they're Orion++. Even better!
The Hafler amps have had their weaknesses exposed by another set of amps on loan from a friend. The system is significantly more free of distortion on peaks, flatter (a bit of midrange bloat is gone), and has more clarity. These problems (such as they were, for the "best loudspeaker [you] ever heard") would appear to be the Halfer's fault, not the ASP's. Still, if the ASP could be simplified, I would be game to try out a simpler design.
To Grey: Extolling the virtues of the soundstage of the LS3/5A while saying the Orions do nothing new with soundstage is like calling the soundstage of an FM broadcast the gold standard, while ignoring live concert hall performances. As remarkable and curious and enjoyable as the 3/5A is (which I have listened to extensively BTW, along with countless other speakers and even, gasp, live music once in a while!) it's not in the same universe as the Orion, and not just in terms of soundstage. Perhaps you need to get out and listen to an Orion?
The RFI-rejection input stage is an analog filter on the input to the next (opamp-based) shelving high pass. So there's nothing to be gained by dumping it. SL also parallels the feedback resistors with small caps so there's no gain for RFI.
For the sake of clarity, there are 21 opamps implementing the 25 blocks shown on the ASP diagram linked to earlier (or optionally 22 opamps and 26 blocks with the optional bass notch filter around U10A. The builder can configure this to deal with one room mode. I turned mine into a switchable BBC dip filter for listening to DG recordings.) The detail-oriented will notice that four of those blocks do not have opamp designators.
Nelson: It's hard for me to see w | | | |
