Yes, how dare I fail to look back through years and nearly 14,000 posts. Did I say anything that was arguing with Lynn's decision? Chill.
lol, 8 and a half years later I still see no decision.
I happen to be a fan of passive line level crossovers, active crossovers and passive speaker level fixes. I find it's very hard to go back to single amping once you get multiamping somewhat figured out.
All Rey Audio systems have always used passive (high level) crossovers only, as you can see in their brochures here: CATALOG DOWNLOAD.
These crossovers are all based on the same topology that was first developed by Kinoshita while still working at Pioneer TAD, i.e.:
- balanced 6th order Low Pass on the Woofer, with Zobel impedance compensation;
- 2nd order High Pass on the Compression Driver, with L-Pad attenuator, parallel-RLC response shaping and series-RLC impedance compensation.
The layouts of these two sections of the crossover are illustrated below in the figures "Kinoshita LP" and "Kinoshita HP".
In my own system, I used the same kind of LP, but I forewent the two RLC networks and instead added a 2nd order LP on the Compression Driver too, complemented by a symmetrical 2nd order HP on the (super)Tweeter.
Of course, there is no point in showing the exact component values, since these are 100% dependent on the specific drive units used and on the chosen crossover frequencies.
Marco
The
Attachments
Or put another way, if you are satisfied with the sound of pro-style multichannel DACs, and multichannel bipolar transistor or MOSFET amplifiers, Gary Dahl's build (and most of the comments in this thread) are probably not the best choice.
You have many more free parameters: efficiency, most of all, combined with the capability of equalizing nearly any driver to do whatever you want. Horns can go out the window unless directivity control is a primary design consideration, and then you'll be looking at OS waveguides, not a LeCleac'h profile. Directivity control and crossover design is whole different topic, and you'll want to read everything that Dr. Geddes has written on this.
If I were in the "modern DACs and Class AB transistor amps are good enough" camp, I'd look at the interesting dipole designs out there. Give them enough amps, power, and equalization, they can do some interesting and unexpected things.
(This opinion based on the dipole Linkwitz and Spatial speakers I've heard at the RMAF and at friend's houses. However, this is a very different sound than my current system or Gary's build.)
Last edited:
I have noted this and it is certainly the way I would go should I go the active route.
This is probably not the most germane thread to discuss the current state of affairs of mainstream residential surround receivers vis a vis the type of system Lynn is describing that Gary has put together. I wish I'd had the opportunity to hear that a couple of months back. His secret underground lab is not an uncomfortable driving distance away, but the currency exchange adds another dimension .
This isn't the first time that you have made these statements in this thread, but honestly I fail to see why, if one is satified with "modern DACs and Class AB transistor amps", then one should no longer seek the many benefits of a loudspeaker system of the type being discussed in this thread.
To me, even assuming that one is not interested in low-power valve amps, this sounds like unnecessarily throwing out the baby with the bathwater.
Now, to provide some context and clarify where I'm coming from:
- I am in no way opposed to low-power valve amps per se
- However, I am also of the opinion that the minimum amount of undistorted peak power that is necessary to reproduce non-compressed musical peaks at realistic levels (e.g., 105 dB at the listening position, corresponding to approx. 80 - 85 dB average levels) is a measurable fact, and not just a matter of conjecture. In my specific case, with 93 dB/W(m) speakers, that minimum power is approx. 70 W (I measured this myself). Your mileage may vary... but not by a huge margin, methinks. So if all one has at one's disposal are, say, 10 W, then one had better have at least >100 dB/W(m) speakers - which means double high-efficiency 15" woofers per side, as a minimum.
- I confess that I am quite satisfied with the sound of most modern decent-quality DACs. This does not mean that there aren't differences among them (there are), but just that, in my opinion, the real bottlenecks are elsewhere.
- Amplification-wise, in my experience the differences start to become more easily noticeable. However, not all "class AB transistor amps" sound the same to me, at all. And, again in my experience, one need not reach for very esoteric amps to obtain a perfectly satisfactory sound (i.e. NOT the "gritty, harsh" sound so often ascribed to class AB transistor amps). In my personal case, for instance, I am quite satisfied with my Denon PMA-A100 UHC-MOS integrated.
With all this out of the way, in my opinion the most critical part of the hi-fi chain remains, by a country mile, the loudspeaker.
And, again in my opinion, regardless of the DAC and amp of choice, there are still ample reasons to prefer a medium-high efficiency two or three-way system based on a large-diameter woofer and a horn-loaded compression driver. And no, it's not just about controlled directivity.
It's also just as much about effortless dynamics.
In fact, to me it's about the combination of higher-than-average directivity with (much) lower-than-average compression.
Even a three way (sub)woofer + cone midwoofer + dome tweeter system (the latter typically crossed at 2-3kHz) just does not sound the same as a (large) woofer + horn-loaded compression driver + supertweeter (with the main crossover point at 600 - 900 Hz). In my experience, NO MATTER how much amplifier power one throws at the former system, the latter one always sounds more 'real' and effortless.
Of course, this is provided that both systems are well designed and executed (e.g., poorly designed and implemented "1 cap & 1 coil" crossovers and the like do not apply, thank you very much).
Anyway - these are just my thoughts!
Marco
Last edited:
Well thought out design goals Marco. There are going to be many different design goals for many different tastes, but I do like and mirror yours. Power and distortion are synonymous and I/many of us don't have the room for the all out horn system, I wish I did. The one place where I differ from you though is with the simple cross-over. I know it's tough to find woofers and CDs that role off where and when needed but if they do, there's no need for the fancy crossover makeup.
In my case the woofer does just that. 94db/1w and I use a passive 1st order. Less is best if one can be lucky enough to get by with it.
In my case the woofer does just that. 94db/1w and I use a passive 1st order. Less is best if one can be lucky enough to get by with it.
I respect that these are your thoughts, and we all need to have these.
However, you are into the SS class A versus AB. The demonstration of the difference is really now a no brainer. If the difference cannot be heard, then the system is opaque i.e indifferent to the fine, but very significant and not subtle qualities of class A over Class AB. To not hear a difference would indicate that the test system is not modern state of the art SS assuming perfect audio source.
My first power amp DIY was a powerful Class A Krell KS50 type back in 1987, but not at all based on Krell design. The speakers were Quad ELS57, SMLE 12" arm, Thorens TD124 Shure V15 III Cartridge and impeccable vinyl with passive preamp. Adjusting the power amp bias current, from power transistor switch on, to full class A showed a continuous gradual transition from horrible flat 2D tizzly SS sound to 3D smooth but very detailed and refined sound. From a cheap supermarket wine to a connoisseurs choice. Take your pick.
And the amplification in many aspects of design are still just as important as the speakers.
We get our own characteristic golden ear for these things. Lynn Olson, Earl Geddes and Gary Dahl all have this is in great degree.
Why is that whenever a test yields answers that we don't like we condemn the test?
Why is that "different" sounding means "better" to the person who is doing the test?
I was once talked into using some guys tube amp on my speakers. Admittedly it sounded different - way different. I was, naturally, curious, so I investigated. Turns out that the high output impedance of the tube amp completely changed the speakers frequency response, and not in a good way. So was this "different", "better"? To me "better" was the way the speakers were designed to work.
It is a fairly easy thing to say that things are "different", its a whole magnitude more difficult to say what is "better".
And I am certainly not a "golden ear" (if that was implied). I have never trusted my own hearing - I've done too many psychoacoustic tests to know that isn't reliable. I rely, for the most part, on measurements. If this were somehow wrong, then I believe that after a decade or more the "error of my ways" would become apparent, but, alas, that has not happened. As things measured better they simply sounded better over the long haul.
Why is that "different" sounding means "better" to the person who is doing the test?
I was once talked into using some guys tube amp on my speakers. Admittedly it sounded different - way different. I was, naturally, curious, so I investigated. Turns out that the high output impedance of the tube amp completely changed the speakers frequency response, and not in a good way. So was this "different", "better"? To me "better" was the way the speakers were designed to work.
It is a fairly easy thing to say that things are "different", its a whole magnitude more difficult to say what is "better".
And I am certainly not a "golden ear" (if that was implied). I have never trusted my own hearing - I've done too many psychoacoustic tests to know that isn't reliable. I rely, for the most part, on measurements. If this were somehow wrong, then I believe that after a decade or more the "error of my ways" would become apparent, but, alas, that has not happened. As things measured better they simply sounded better over the long haul.
As this variable should have been eliminated, my take away from this is simply that the guy in question should have known better before 'insisting'. As to how it might have sounded, would just be speculation.
My experience with a good performing amp that adds a little 2HD with a system that doesn't require that kind/amount of 'assistance', is that I find myself wishing it wasn't there.
I did not mean to imply that "Class A and Class AB amps sound the same".
I was just taking exception to Lynn's statement that " if you are satisfied with the sound of pro-style multichannel DACs, and multichannel bipolar transistor or MOSFET amplifiers, Gary Dahl's build (and most of the comments in this thread) are probably not the best choice".
Marco
I'll run it up the flagpole again and see if I can make it a little clearer.
* If the option of 100-watt amplifiers is available, there are more degrees of freedom in the loudspeaker. More drivers are available, and more equalization can be applied.
* If multi-amping is on the table, the crossover can precede the amplifier, which lowers amplifier IM distortion. More headroom is also available, since clipping in a band-limited amplifier is less audible. This represents another degree of freedom in the overall system design.
* If digital equalization is available, driver delay compensation and crossovers that are non-minimum-phase can also be applied. This is another degree of freedom in the overall system design.
With the constraint of low-powered (and expensive) Class A triode amplifiers, and expensive DACs, these options are not available. A speaker can still be designed, but there aren't as many choices available ... they tend to converge on a large-format monitor speaker or an all-horn system.
My original point was simply that folks with high-powered amplifiers, and the ready option of multi-amping, have (many) more choices. There's no reason to pointlessly restrict the system to the parameters of the "Beyond ..." discussion.
* If the option of 100-watt amplifiers is available, there are more degrees of freedom in the loudspeaker. More drivers are available, and more equalization can be applied.
* If multi-amping is on the table, the crossover can precede the amplifier, which lowers amplifier IM distortion. More headroom is also available, since clipping in a band-limited amplifier is less audible. This represents another degree of freedom in the overall system design.
* If digital equalization is available, driver delay compensation and crossovers that are non-minimum-phase can also be applied. This is another degree of freedom in the overall system design.
With the constraint of low-powered (and expensive) Class A triode amplifiers, and expensive DACs, these options are not available. A speaker can still be designed, but there aren't as many choices available ... they tend to converge on a large-format monitor speaker or an all-horn system.
My original point was simply that folks with high-powered amplifiers, and the ready option of multi-amping, have (many) more choices. There's no reason to pointlessly restrict the system to the parameters of the "Beyond ..." discussion.
Last edited:
Surely! I have no problem agreeing with this.
BUT, this other statement I do not agree with:
Lynn Olson said:
Why "probably not"? In my opinion, it may well still be!
In other words, while it may be that it was your amp's and DAC's specific characteristics that led (or even forced) you to adopt this type of loudspeaker, this does not mean that the loudspeaker itself may not still be the "best choice" for many others who do not have those same constraints in terms of amp and DAC (for the valid reasons that I hinted at before, namely essentially high directivity and effortless dynamics).
I rest my case
Marco
My personal thinking on 'BTA'-style systems at the moment is that it should be a 4-way, and you need to get the bass on its own amp, to ease the demand on the valve ( tube ) amp . If you run a 12" or 15" sealed-box unit with a good solid-state amp, you can go up to around 200 to 250Hz without too much loss of fidelity . Then the upper three channels ( two horns and a tweeter) are limited by the tweeter sensitivity, that can be at least 100dB without too much expense. You should be able to run these three and their crossover OK with a moderate-size PP valve amp or a bigger transmitter-valve SE . I don't think, despite the possibility of using double 15's for bass to get sensitivity up, you could really run that whole lot and a 4-way crossover with a valve amp .
So the crossovers would be 250Hz, 800Hz and 5000Hz ; a horn of around 160 to 180Hz, one of 400-500Hz and the ribbon.
ps. I have found that you can attenuate with resistors on a compression driver if you pick the right sort of resistor - only the planar ones from eg. Caddock, Vishay or BI Industries. With these you can get at least 6dB of attenuation without any perceptible loss of tone or dynamics, from my tests with the GPA 288H and Radian 745NeoBe .
So the crossovers would be 250Hz, 800Hz and 5000Hz ; a horn of around 160 to 180Hz, one of 400-500Hz and the ribbon.
ps. I have found that you can attenuate with resistors on a compression driver if you pick the right sort of resistor - only the planar ones from eg. Caddock, Vishay or BI Industries. With these you can get at least 6dB of attenuation without any perceptible loss of tone or dynamics, from my tests with the GPA 288H and Radian 745NeoBe .
With respect to DACs, there are some really good multichannel DACs coming to the market that sort of ease the burden of requiring multiple stereo DACs. One off the top of my head is Merging Hapi, which is basically a Merging NADAC except in a pro use rackmount enclosure.
European Triode Festival 2015 report by Hartmut Quaschick ...
European Triode Festival 2105 report by Thomas Mayer ...
The last time I went to the ETF was in 2004, as one of the speakers. Hmm ... maybe the 2016 ETF is a possibility.
The ETF'ers are a great bunch of people, and I'd like to see them again. Way more fun than commercial hifi shows, and a lot of really creative out-of-the-box thinking.
European Triode Festival 2105 report by Thomas Mayer ...
The last time I went to the ETF was in 2004, as one of the speakers. Hmm ... maybe the 2016 ETF is a possibility.
The ETF'ers are a great bunch of people, and I'd like to see them again. Way more fun than commercial hifi shows, and a lot of really creative out-of-the-box thinking.
Last edited:
I've not heard them <strike>nor looked at the specs of these</strike> but Lynn outlined his preferences (and some reasons for them) a while back in PF
Part One:
Positive feedback Issue 65: On DACs
Part Two:
Positive feedback Issue 66: On DSD
[Edit - it seems they use a Sabre ESS 9008 DAC (Merging’s Ethernet NADAC impresses at Munich High-End 2015 John H. Darko 22.05.2015) i.e. Delta Sigma. But they've replaced lossy USB with (theoretically) lossless TCP/IP which should have removed one weak link. ]
Last edited: