Are audio companies all involved in a huge conspiracy? - Page 47

Given that there is content in movies as low as 3Hz, a realm that is arguably more sensed/felt than heard, is it reasonable to expect that DACs as a whole still perform largely indistinguishable from one another?

It takes a ton of SPL to actually feel 3 Hz, and it is the truly rare subwoofer that can actually conjure it up. That all said, there are a lot of DACs that have response down that low and bekow. There's nothing that is commonly used in the digital domain side of a DAC that changes its LF response. There are usually at most 2 parts (often omitted) in the analog domain side that change LF response.

A quick review of DAC and digital player schematics suggests that it is not unusual to build these at all price levels with response down to DC or very close (less than 3 Hz) to it.

Even my $35 Sansa Fuze ultra-portable fits into this category and has response down to DC. This was done BTW in order to make it easier and cheaper to build it so small.

A) You didn't carefully read what I wrote. Or something.

B) You're hellbent on arguing semantics. Why? Use whatever vocabulary you wish, did you understand and accept the essence of my post?
Sure. And bring it on brother! We could use some exciting fresh data. As has been said, it should be fairly clear what standards are required of such head turning data. Do you think your livingroom observations qualify? Anyone's on avs? Why not?

Right!

Chu Gai:

You would also quite commonly end up in trouble with the DC-protection circuits in the amps. Most power amps will have rolled off quite a bit at 3 Hz. Out of all my power amps, the Denon POA-2800 is probably the one that goes the lowest with -3dB at 1Hz.

It's also happened that some receivers will trigger protection circuitry if they get such a low signal - I've heard of once case where even the DC-offset protection fired over an extreme ULF signal.

So I think you have a lot of stuff to go though and verify before you worry about the DAC.

3Hz in a movie - is that the destruction of Earth in The HitchHikers Guide to the Galaxy one?

What makes you say so? Any controlled subjective listening test of digital audio kit must by definition have a DAC in the signal chain, right? Therefore, with the exceptions of tests about different transports (disk spinners or computers) feeding into a common DAC, every test involving digital audio kit is also a test of different DACs.

When you can show a seriously-conducted (level matched, blind) listening test of DACs that shows a sonic difference in the absence of phenomena well known to allow differentiation (FR errors, audible hiss/buzz/hum, etc.) then...you should publish it. But until then, let's just agree that for all relevant and material purposes the matter is entirely settled.

No. Production of art is an entirely separate discipline from reproduction of art. Often the problem in these discussions come when people come in with a confused and insufficiently rigorous thought process, such as the one described in words above, and therefore fail to understand the fundamental distinction between production and reproduction. And, of course, audio parts makers/marketers love it when that distinction is blurred, because it raises their collective status while allowing higher markups.

But the bottom line is that audio is to photography as a photo-copier is to a symphony.

It shouldn't be, if you want it actually done right. Alas, just as getting reproduction of a 2D visual piece of art (such as a photograph) right one probably does require to looking at boring and tedious things such as prints of pictures of brick walls, getting reproduction of a 3D audio piece of art (a song, a symphony, spoken word, ambient noise, whatever.) right in a room requires looking at boring and tedious things such as steady-state frequency response in the modal region, direct-field response of the loudspeakers, polar maps of the loudspeakers, etc.

LF roll off is almost always determined by the series cap at the input of the (usually) DC coupled amplifier stage. It might also be in a servo. This ensures that no DC from an up stream component is amplified.

It is possible some extreme LF may trip some protection circuits, but that does not relate to the LF roll off in any amp I've seen so far.

Exactly.

No, that was about pre-amps/receivers, not poweramps. But the point was that there are other aspects to check before one needs to worry about the DACs linearity at 3Hz.

Quite so and there are a few folks, some using commercially available subs and others embracing the DIY route, that are using multiple subs in order to achieve or reproduce content that goes as low as 3kHz with authority. Hence my question posed earlier. Are there differences among DACs with respect to their linearity down to 3Hz? Arny replied with his engineering assessment of the circuitry however I'm looking for either manufacture's specifications ideally with measurements.

To clarify things, these days the low frequency extension of DACs and music players are not being set by the DACs and music players themselves but rather by the equipment they drive.

Testing FR down to 3 Hz is rarely supported by common test equipment.

From the Audio Precision Web site:

The better audio generators available in 1993 have frequency ranges extending from 10 or 20 Hz at the low end to 100 kHz or more at the high end, maximum amplitudes of +28 to +30 dBm, minimum
amplitudes of –70 to –90 dBu, residual distortion from 0.0005% to 0.003%, absolute accuracy of 0.1 to 0.2 dB, and frequency response flatness of ±0.05 dB or better.

Not that much has changed since 1993 as the specs for one of their current test sets (AP 2700 series) says:

http://www.ap.com/download/file/183

"Frequency Range 10 Hz–204 kHz"

I felt tired.

It still applies because all of the AVR schematics I've seen have a DC blocking cap at the input of the poweramp stage, as well as before the ADC for analogue sources.
Couldn't agree more.

I don't think that even the reproduction of audio is that simple. Otherwise we wouldn't have such a diverse range of speakers on the market and it would be nailed down by now. Everyone's tastes are different. Heck, even the professional experts can't agree on room acoustics with each other.

I think that people that focus too much on the numbers and charts of things can lose sight of the bigger picture. Much like those soulless camera gear owners I mentioned before. Human psyche (which as of yet no one fully understands) plays a big role.

Correct and until they agree to strict standards sound reproduction calibration is a moving target. But make no mistake there's only one correct way of reproducing a recording. Just like there's only one correct way of calibrating a TV or projector. Whether you like how it looks or sounds is an entirely different topic. You can use a pen and add things to a Picasso if you don't like the original. That's entirely up to you - if you own the picture

Notable is that the tastes are much less different when tested blind.

It may help to see where he is coming from: http://www.avsforum.com/t/1438570/low-vs-mid-vs-high-priced-dacs/150#post_22924542

Your evidence has absolutely nothing to do with your conclusion. You need to think more rigorously.

After all, there are a diverse range of wires on the market. What does that say, except that audiophiles are gullible?

I'm not honestly sure that's true, when just sound is evaluated. There does seem to be a broad convergence about what's actually desired. You need to read less marketing propaganda, and more science.

But change your statement to "people think their tastes are different," and that's certainly accurate.

Perhaps because that makes it easier to sell things.

Again, production vs. reproduction. Why use an analogy again when you show or should know that it's it's the product of inadequate thought?

That's an easy one, it's because the buying market demands it. If there's someone willing to pay $250,000 for a pair of speakers, someone will make them....

Yup, but taste can be influenced.

See the above, you can't argue room acoustic effects, just preference, and that's where it gets off the rails...

I think that you may be poorly informed when you presume as you seem to being doing above, that people choose speakers that match their sonic tastes.

Often their tastes end up matching their speakers.

Furthermore, the way that speakers sound is profoundly affected by your listening room and where you put the speakers in it.

So even if you have the sound you prefer, what you prefer is not the inherent sound of the speakers because arguably nobody knows what that is since speakers have no inherent sound. Speakers always sound like the interaction of the speakers and the rooms they are in. Since the rooms are generally different, in real world use there is no such thing as just one sound of a speaker.

I think that people focus too much on the sound they perceive from their audio systems, for the reasons given above, and many other reasons.

The interesting thing is that many of the performance numbers for a speaker actually represent the properties of that speaker. Think about it - speaker performance numbers are usually measured in an anechoic chamber which is actually an attempt to simulate having no room at all.

Supposedly audiophiles are music lovers but many seem to be in love with shopping for equipment.

So true.

So, what particular speakers do you use then?

Why do we have vastly different speakers like line arrays or electrostatic or planar or horns or 2-way monitors or large towers?

If there was indeed only one "true" way to reproduce audio... then wouldn't there be a much more narrowed down selection to choose from?

Much of that relates to custom and belief as compared to actual sound quality or taste.

I suspect that I'm not communicating well - I know that there are many ways to achieve what is basically the same sonic outcome. There is not just one true way, no matter what some vendors attempt to get people to believe.

Have you got your listening room to that level?


But that Picasso is already a colored abstract of reality of someone's artistic interpretation. It's not meant to be an accurate window of reality. But yet it is still something that many people find beauty or inspiration in and would like to hang on the wall. The same could not be said for a print from a soulless camera gear collector that may have some of the sharpest and most accurate colour reproducing lenses available today but doesn't have an artistic bone in his body.

Think about the difference of this that goes beyond what 'science' can measure.

Not sure why my listening room is relevant?

So is a recording.

You said... "But make no mistake there's only one correct way of reproducing a recording."

So if you believe this... then have you been able to achieve this with your room?

Paradigm Signature S8 v.3's.... cause they're purdy...
Why?

As to why there's different types of speakers, well it's not rocket science, it's because there's more than one way to create and direct soundwaves.

Well then that's obviously the only speakers anyone would ever need so we may as well stop production of every other speaker and only make and sell Paradigm Signature S8 v.3's then.

Sorry, you lost me. This makes absolutely no sense, at least that I can come up with....

x
Edited by kraut - 3/5/13 at 9:03pm

Go back to the start of our conversation... http://www.avsforum.com/t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/1380#post_23009861

You seem to think a lot of other speakers are unnecessary. "you can't argue room acoustic effects"... so then I take it you have achieved the ultimate and most faithful audio playback with your particular speakers so the rest of us may as well save all the bother and just buy the same speakers you have then.