I'm only making a proposal.
To pull this off, I'd need a collaboration. My time is limited to on occasion posting in these threads... probably could do "project management".
_-_-bear
But I envisioned 2 channels per string. So 4 channels total.
Opamp minutiae are somewhat petite for somebody mostly measuring on speakers like me. The end goal is flawless measurements speaker side. Electronics are just a link in a chain, and linear electronics are old school in speakers. In modern active loudspeakers, the electronics feeding each driver are non-linear by design, compensating for driver quirks and acoustic phenomena. The design proces invariably starts with acoustic measurements.
Designing a loudspeaker by measuring and modelling electric behaviour is approaching the horse from the wrong side. This is also true for analog of course, but that would be a mule.
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Mules, I am told, are sure footed.
fwiw...
however this fails to explain why it could possibly be possible to hear anything resulting from the electronics
at all, yet it seems that we do.
_-_-
fwiw...
however this fails to explain why it could possibly be possible to hear anything resulting from the electronics
at all, yet it seems that we do.
_-_-
Bear, I am not satisfied by 'seems that we do'. Either we do or we don't or we don't know.
Edit: this might be a bit too digital.
Edit: this might be a bit too digital.
This is in the same direction as asking whether forum posters really exist or they just seem too exist..... Vacuphile, you're bringing the discussion back many centuries.... 😀
vacuphile,
If people would spend a 1/4 the time they do on the electronics side on their speakers and finding out what is going on there perhaps most of these silly conversations would become much less contentious.
Scott,
I can completely comprehend how someone with your electronics background would approach speaker design the way you did. I have always found the simplified lumped electrical parameters used to be rather simplistic or might I say misplaced for designing speaker systems. There are so many interactions between the electrical side and the mechanical side, plus real enclosure factors just don't lend themselves to simple solutions. The days of simple computer generated xo's that don't take into account the actual impedance of a device are just one of the real problems with so many speaker systems. It wasn't that long ago that I thought that moving from passive to active xo networks was a good solution. With modern DSP controls those solutions now seems so yesterday, you can do so much more once you leave the analog xo paradigm. The other factor is starting with a great working physical device in the first place, way to many speakers are nothing more than a combination of off the shelf commodity pieces thrown together. I think some software such as FineCone and FineMotor also lead down the garden path to mediocrity.
If people would spend a 1/4 the time they do on the electronics side on their speakers and finding out what is going on there perhaps most of these silly conversations would become much less contentious.
Scott,
I can completely comprehend how someone with your electronics background would approach speaker design the way you did. I have always found the simplified lumped electrical parameters used to be rather simplistic or might I say misplaced for designing speaker systems. There are so many interactions between the electrical side and the mechanical side, plus real enclosure factors just don't lend themselves to simple solutions. The days of simple computer generated xo's that don't take into account the actual impedance of a device are just one of the real problems with so many speaker systems. It wasn't that long ago that I thought that moving from passive to active xo networks was a good solution. With modern DSP controls those solutions now seems so yesterday, you can do so much more once you leave the analog xo paradigm. The other factor is starting with a great working physical device in the first place, way to many speakers are nothing more than a combination of off the shelf commodity pieces thrown together. I think some software such as FineCone and FineMotor also lead down the garden path to mediocrity.
Not sure what you are thinking or saying.
Certainly speakers do not "sound the same"?
You'd have to say if in your experience speakers driven by (let's narrow it down) solid state amps with a DF >50 and a THD <0.01% (pick your number here) all sound the same to you or not. By this I mean a given speaker driven by different amps... I assume that you find speakers to sound rather different from each other??
Speaking by way of my anecdotal self, I find that speakers vary wildly and amplifiers vary quite a bit, especially when driving speakers.
Not sure about the "we" except to the extent of the "royal we" being cited.
How about you? (or anyone else)
_-_-
Bear,
Leaving out whether there are opamps or not I can assuredly say that I have never heard two different amplifiers that sound identical to each other. Why that is so I would not honestly know but I would say in a blind test I could hear differences between two amplifiers. I am not saying that one would necessarily be better than the other, just that they won't sound identical. Some may love vacuum tube amplifiers which is okay but even there a MacIntosh will not sound like a Cary or a vintage Fischer. Each has their own distinct sound qualities.
Leaving out whether there are opamps or not I can assuredly say that I have never heard two different amplifiers that sound identical to each other. Why that is so I would not honestly know but I would say in a blind test I could hear differences between two amplifiers. I am not saying that one would necessarily be better than the other, just that they won't sound identical. Some may love vacuum tube amplifiers which is okay but even there a MacIntosh will not sound like a Cary or a vintage Fischer. Each has their own distinct sound qualities.
That's the case from what I've heard, and also in unit-to-unit variation of a given model in production.
I agree with much of what you say but you are going a bit too fast here.
My latest 3-way design with analog xo measured better than a heavily DSP'd high-end 3-way from a renowned designer; Jan Didden and I recently measured anechoically.
Most low-Q corrections can easily be achieved by analog means. If there is a need for high-Q corrections, this in my experience usually points to more fundamental driver/enclosure related issues that are better dealt with at ground level.
The problems I see with DSP correction: 1) it makes loudspeaker designers lazy, because the cause of errors should be corrected first, and not the effects. 2) DSP based correction is what, 90dB distortion at best? I get 105dB with analog designs routinely. Nothing wrong with op-amps. 3) Price and complexity. A handful of NE5532's, resistors and CoG caps is much cheaper than any DSP based solution. DSP is more complex because it adds a digital dimension to an otherwise analog chain. 4) Latency.
The only correction you cannot do analog is turning back the phase rotation caused by the filtering. Add very long delays to that, but these are not required in any proper loudspeaker design. Since this phase rotation is inaudible for all intents and purposes, certainly through speakers, who cares anyways? But here is the fun part. There is no reason to make the loudspeakers linear phase. You can always put a DSP between your speaker and the source as a separate add on if you insist on having linear phase.
If you know the target curves for your speaker, just send them to me and I'll see if I can do an analog xo in your specific case, just for sports.
vacuphile, I'd like to see your speakers (at least online).
also, you are talking mostly about flat frequency response... so I am saying that it is entirely possible that by changing the opamps in your analog active xover that you will hear changes in perceived sound quality. And that the results will depend on the choice(s) of opamps.
Have you tried this?
also, you are talking mostly about flat frequency response... so I am saying that it is entirely possible that by changing the opamps in your analog active xover that you will hear changes in perceived sound quality. And that the results will depend on the choice(s) of opamps.
Have you tried this?
I might have a picture of my failure. 🙂 I even hand planed a fancy curved front panel out of solid mahogany before listening to a mockup.
Bear, what I know is that some opamps are easier to work with than others. Would not just replace in a circuit for example OPA2134 with LM4562 and expect them to sound the same. LM4562 might start oscillating at 20 MHz and pick up RFI at the same time, send and receive in one go. Horses for courses. Mooly has done an enormous service to the audio community by providing test files, which at least have convinced me that the best opamp is the opamp that fulfills best the technical criteria of the design.
In other words, I have full confidence in my inability to distinguish between adequate opamps ears only.
About my speakers: I have some serious concerns about IP protection at the moment which I have to sort out first. Money is solidified human energy, and I want that returned with a modest but appropriate gain factor. Therefore, no picture of the speaker, but rather of a telling measurement: distortion @ 100 dB @ 1 m. That is a LOUD sweep, even in an anechoic chamber. (I have a promising candidate for a better tweeter, because there is something to be gained there, but look at distortion @ 40 Hz! Anybody knows of a medium sized speaker with better metrics?)
Just for bragging rights here the plot of a lesser speaker, over ten times heavier than mine:
Edit: What Harman has going for it is that they calibrate the scales on their measuring equipment better. SPL in my measurements were set by independent metering.
Edit: What Harman has going for it is that they calibrate the scales on their measuring equipment better. SPL in my measurements were set by independent metering.
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vacuphile, a discussion of speakers is for another thread.
but "might start oscillating" and is oscillating are two different things.
So, it seems that you are unwilling to ever try another opamp - even when it tests ok - into one of your active xovers?
And, I wonder what that RFI is going to do, and why the circuit is permitted to pass anything that high in frequency, especially if it is a bandwidth limited filter and bandwidth limited application? How is the RFI going to get into the box with the circuitry. I'm assuming you do something at the input to kill RFI, especially local AM broadcast stations??
But seriously, give some other "safe" opamps a listen, even compare the 5534 to the one you cited? Especially on the bass and especially on the tweeter section... feel free to report back if you hear nothing...
but "might start oscillating" and is oscillating are two different things.
So, it seems that you are unwilling to ever try another opamp - even when it tests ok - into one of your active xovers?
And, I wonder what that RFI is going to do, and why the circuit is permitted to pass anything that high in frequency, especially if it is a bandwidth limited filter and bandwidth limited application? How is the RFI going to get into the box with the circuitry. I'm assuming you do something at the input to kill RFI, especially local AM broadcast stations??
But seriously, give some other "safe" opamps a listen, even compare the 5534 to the one you cited? Especially on the bass and especially on the tweeter section... feel free to report back if you hear nothing...
vacuphile,
I agree that the first thing you have to do is optimize the devices before anything else. Once you have that device and you aren't going to change anything mechanical to make any improvements the next step is the network to combine units and make any needed corrections.
I've seen some simple and some complex passive networks, yes you can do things with a passive network. DSP control just brings many other nice things like simple time alignment and phase matching.
I agree that the first thing you have to do is optimize the devices before anything else. Once you have that device and you aren't going to change anything mechanical to make any improvements the next step is the network to combine units and make any needed corrections.
I've seen some simple and some complex passive networks, yes you can do things with a passive network. DSP control just brings many other nice things like simple time alignment and phase matching.
1) that's not a problem with dsp, bot with the person.
2)huh. Use better dsp.
3)agree with price and complexity, but with most sources being digital why not keep it digital all the way to the amps?
4) so what, you can't wait a few milliseconds?
It was a real life example where 4562's driving relatively short interconnects had to be decoupled resistively to prevent oscillation, whereas other opamps did not misbehave.
I have tried OPA2134, LM4562, NE5532, 833's. My search for better sound has always been driven by things that did not quite sound right to my ears, and all these opamps don´t seem to create audible nasties. But frankly speaking, what would life have been if my ears hadn´t been shot at least somewhat by now. My predilection for measurements is the result of the realization that dials tell more than my ears probably ever did in their best years.
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