What is it that makes a good audio out?

[tfarney]

Sorry, Daphne, I didn't get through all that, but I don't think we're focused on nonsense, or even on double-blind testing, we're just discussing a way in which the audibility of something can be reliably tested. All of the caveats you put forth, some of which are valid and some of which do not appear to quite understand either the methodology of objectives of the testing, are addressed with properly conducted tests. The challenge is not conducting an AB/X test that accurately determines if a tweak (yes, they are typically subtleties being tested, there is no need to test the audibility of that which is not subtle) can be heard. I think that may be the key to most of your concerns. Long listening sessions, critical evaluation and subjective judgments are not required. We are only determining whether or not something can be heard at all.

 

Tim

 

[audioengr]

I wont go down the AB/X rathole. It's like a lie-detector test. Not entirely reliable. And getting the RIGHT people (trained listeners) to come and sit still for hours is virtually impossibe. And then people still find flaws in your method or believe that it is a hoax. Not worth the time and effort unless maybe sponsered and overseen by a third-party such as Stereophile or TAS.

 

"If the $10k preamp is required to even hear the jitter, how can the jitter possibly be the most important source of noise?"

 

It's not required. The problem is that there are so many causes of sibilance in the typical system, the preamp only one of them, that many audiophiles dont get the FULL benefit of low jitter once they have it.

 

We are all at different levels of system perfection. If you are still tuning the sound with different cables for instance, you are not even close.

 

The reason that I put Jitter as #1 is because of customer feedback. This is what they are telling me, based on experience with MY jitter reducing products. Some of my customers also have world-class systems. They hear what I hear.

 

Steve N.

Empirical Audio

 

[audioengr]

"professionals who conduct blind tests for a living, don't

make up the parameters as they go along."

 

These "professionals" however may be limited in the system quality that they are using, the room acoustics or even having good tracks to use. I have heard systems of some high-end reviewers, and so few of these are good enough and that I would never send anything to them for review.

 

I have read reports of AB/X jitter tests and they are consistently filled with flaws, particularly the ones published by AES. They dont use good enough systems and they dont use good enough tracks. In some cases, they dont even use trained listeners. In some cases, they use contrived jitter stimulus, not related to a music track at all, just random and uncorrelated. The results are totally useless and misleading IMO.

 

Steve N.

Empirical Audio

 

[The Computer Audiophile]

Hi Guys - I've been following this one and thinking about it quite a bit. I guess I just don't get the attraction to the "issue" of testing v. not testing etc... The whole thing is so far from kicking back, enjoying music, and the rest of our wonderful hobby. If something sounds good thats all that matters. Test all you want, don't test all you want it doesn't really matter to me. If I listen to a component and it sounds good I'm happy. If a manufacturer claims better sound because of lower jitter I'm cool with that. If I can hear it great, if I can't oh well.

 

OK, carry on :-)

 

[tfarney]

"Hi Guys - I've been following this one and thinking about it quite a bit. I guess I just don't get the attraction to the "issue" of testing v. not testing etc... The whole thing is so far from kicking back, enjoying music, and the rest of our wonderful hobby. If something sounds good thats all that matters. Test all you want, don't test all you want it doesn't really matter to me. If I listen to a component and it sounds good I'm happy. If a manufacturer claims better sound because of lower jitter I'm cool with that. If I can hear it great, if I can't oh well."

 

Point well taken, Chris. What we hear is what matters. It all started because someone asked about the difference between the digital output of a Mac and what he would get if he ran it through something like the Trends UD-10. The Emperical Audio box was offered as a superior solution. I guess the question is, "is it?" Heck, I own a UD-10. It re-clocks. Is it better? I don't know that answer, either, but there is a way to determine whether or not a difference can be heard, thus the AB/X discussion. But you're right, in the end it amounts to what you hear, and evidently even one of the best jitter-reduction devices in the business (Emperical Audio's) can only be heard if you have equipment of such a quality as to exceed that of the reference systems of even audiophile magazine editors.

 

Which makes it a moot point for the overwhelming majority of us.

 

Tim

 

[mpmct]

"... evidently even one of the best jitter-reduction devices in the business (Emperical Audio's) can only be heard if you have equipment of such a quality as to exceed that of the reference systems of even audiophile magazine editors.

 

Which makes it a moot point for the overwhelming majority of us."

 

Exactly.

 

 

 

 

 

 

 

 

 

 

 

 

 

[mpmct]

"If something sounds good thats all that matters. Test all you want, don't test all you want it doesn't really matter to me. If I listen to a component and it sounds good I'm happy. If a manufacturer claims better sound because of lower jitter I'm cool with that. If I can hear it great, if I can't oh well."

 

 

Chris, on balance, what does the M.O. you described above cost you annually?

That's a serious question. Would it be unfair to think that you must be pretty flush

to have the attitude about audio equipment purchases that what you're written describes?

Do you just buy, try, and ship to a-gon or similar if you don't like, and eat the difference?

Or do you just live with it, call it one more secondary system, and put it in a back room?

Or, do you get 30 day money-back guarantees, shipping included? If yes, where do you shop please?

 

I want to be sure I understand what it seems to me you've implied: us consumers

should assume that reviews are 'true', or 'truth-y', and that any and

all manufacturers' claims are too, and that we should buy on that basis,

and expect to take the requisite a-gon downer if we just don't 'hear' it? Yes?

 

 

 

 

 

 

 

 

 

 

 

[tfarney]

I'm not Chris, nor do I play him on TV, but I'd assume he has good dealers available to him where he lives, does not buy over the internet, and purchases only what sounds good to him. Fair enough. But I also happen to think it's fair to expect the manufacturers of very expensive equipment to show some evidence of the effectiveness of their products in the real world.

 

Tim

 

[The Computer Audiophile]

Tim - Pretty much right on. I don't buy anything without hearing it. If there isn't a way to work out some kind of listening session(s) with a product there's no way I'm dropping any cash on it. If I enjoyed reading specs on a nice quiet evening and looking at my audio components then I'd buy anything based on specs and marketing. But, I enjoy listening to music as we all do, so listening to a component is a must. Since there are a plethora of great components available today there is usually a way to work out something where you can listen to a product. Between manufacturers, brick & mortar dealers, and online dealers there should be a way to have a listen. If not, move on to the next component.

 

mpmct - I think we have a little misunderstanding and we probably agree.

 

I said "...If a manufacturer claims better sound because of lower jitter I'm cool with that. If I can hear it great, if I can't oh well."

 

I think you assumed I purchased the equipment already. This M.O. is really before I purchase anything. If I can hear the improvement, great I may purchase the component. If I can't hear it I then I really don't care and I move on, hence the Oh well comment. Manufacturers of all products make claims that not all of us agree with. Fortunately we aren't forced to purchase something that doesn't live up to the claims.

 

I hope you were being a bit factitious about assuming all reviews are true and we should believe manufacturers claims blindly. That is very far from my belief.

 

On a side note, there is something to be said for purchasing equipment that may not fully be appreciated at the time of purchase. This is because we usually seek to upgrade components one at a time. Buying a DAC with ultra low jitter may not benefit someone now, but if they upgrade the rest of their system later on then the DAC purchase was money well spent. As long as they have heard the claimed benefits in a dealer's system etc...

 

 

 

 

[audioengr]

I have offered demos in the past. It's a can of worms. Had one customer keep one for 6 months. And offering money-back is a no-win also. The equipment takes about 30 days to fully break-in, so initial listening tests may cause lots of errant returns. No thanks.

 

If I had a problem selling my jitter reducing devices, then maybe I would resort to these kinds of things, but I've had a 3-5 month backlog for about 2 years now. Just watch Audiogon and see how long one of my devices sits there for sale, when they rarely come up for sale. Usually one day. I dont advertise either. All word of mouth and reviews.

 

Steve N.

 

[tfarney]

Steve, given the extreme rarity of the system and the customer, as you've described them, who can actually benefit from your products, no, I don't imagine home demos worked well for Empirical Audio. You would have to pre-qualify both the ears of the customer and the resolution of his system to determine that he would actually be able to hear your product before ysubjective evaluation would be meaningful. An impossible challenge.

 

Fortunately, it seems that you're selling all you can build, that those rare audiophiles whose ears, taste and gear are up to the task of hearing Empirical Audio's products are finding you.

 

Congratulations.

 

Tim

 

[Roseval]

Still, the measurements I've seen are so small that I have to wonder how, even with the gear of the gods, humans can hear timing errors measured in picoseconds with ears working in 4/4 time .

 

Like all our senses out hearing has a upper and a lower threshold.

Claims about the lower threshold for jitter varies from 250 ns to 20 ps depending on the architecture of the DAC and the frequency.

 

Sound coming from one direction will reach the ear furthest away later than the closer ear. We can discern approximately 1/500 second time lag.

Hearing differences due to sample rate fluctuations in the order of 250 ns is of course far below the threshold of our hearing.

Having proven now that jitter is inaudible, next question is can we hear two tones of different frequencies at the same time if both of them are loud enough.

The answer is an obvious yes. I think this is the core of the jitter phenomenon. The way sample jitter is mapped into the analogue domain by a DAC creates artefacts like side bands. If the energy of these side band is big enough they become audible.

 

http://thewelltemperedcomputer.com/KB/BitPerfectJitter.htm

 

 

[tfarney]

Thanks for the explanation. Do these artifacts manifest themselves in something that is measurable? Never mind. It seems that for me, it is a pretty moot point anyway. Those artifacts are, evidently, minor enough that I would have to first posses a system so resolving as to exceed the reference system demands of many audiophile journalists, then I'd need to train my ears to hear the difference between the presence and the absence of the artifacts. That just doesn't sound like a process that would facilitate the enjoyment of listening to my redbook cds of Live at the Village Vanguard or The Wild, The Innocent and the E Street Shuffle.

 

Tim

 

[Ashley James]

I think enthusiasts discussing jitter and it's likely impact on what they hear is a bit like car enthusiasts discussing rocker arm performance in race cars. Both are a tiny part of a jigsaw that gives us the result as music.

 

In reality jitter is only an issue when A to D 'ing or D to A 'ing, the first isn't usually of concern to hi fi enthusiasts and the latter is well catered for by modern DACs and their attendant circuitry. Therefore if it doesn't sound right, it's best to admit you don't know why.

 

As far as digital outputs go, they are all as good as one and other for hi fi provided the DAC is designed to cope with the slightly different artefacts each produce.

 

The optical output looks to become the International standard, it's certainly the most popular now, although people worry that 24/96 is its highest sample rate. We don't think that anyone need worry about it because we've done a series of tests and not been able to hear any difference, so we've involved others by asking them to switch between options using an IR handset and telling us what they hear. These were a cross section of pros, enthusiasts and just passers by, who often hear as much as anyone. After all we're all expert listeners, though we may not be experts at interpreting what we're hearing.

 

Our experiment was switching the sample rate on an experimental DAC while listening to music. We were able to go from 32 kHz and 16 kHz bandwidth to 24/196 and not hear a difference, which is as science dictates it should be.

 

I don't doubt some will think we're all deaf, but I hope it re-assures others that the optical output is good enough for anything hi fi, provided a modern DAC that's been auditioned before purchase is used.

 

These days, IMHO there are far more problems in the rest of a system than in the source.

 

Ashley

 

[Roseval]

Do these artifacts manifest themselves in something that is measurable?

If you would have bothered to use the link I provided, you can see that a FFT analyzer can measure it

 

just doesn't sound like a process that would facilitate the enjoyment of listening to my redbook cds of Live at the Village Vanguard?

 

You can choose between listening to music (recommended) and listening to equipment (some times needed).

Live at the Village Vanguard will always be involving regardless of the equipment because it is good music while boring music in high resz on the highest high end equipment will sound like what it is, boring.

 

[Roseval]

I think enthusiasts discussing jitter and it's likely impact on what they hear is a bit like car enthusiasts discussing rocker arm performance in race cars. Both are a tiny part of a jigsaw that gives us the result as music.

 

Agreed, that’s the right perspective.

 

As far as digital outputs go, they are all as good as one and other for hi fi provided the DAC is designed to cope with the slightly different artefacts each produce.

 

I’m afraid that’s the point, a lot of DACs are build like analogue equipment, accept the input as it is. The modern ones recover the clock. I’m inclined to say that if you hear differences between bit identical source or given a source different cables or transmission protocols, it is a badly designed DAC

 

I don't doubt some will think we're all deaf, but I hope it re-assures others that the optical output is good enough for anything hi fi,

 

I know your AMD9.1 offers optical input (Toslink) only. As far as I could judge not to many PC brands offer optical out (Apple, Toshiba). Why not adding a USB? The modern DACs you are using must be able to cope with USB jitter.

 

 

[Ashley James]

Jitter manifests itself as an increase in distortion and or noise in the experiments we did.

 

We did make a USB only ADM9 but it didn't sell, presumably because the computer is not where the hi fi is. Most customers use Sonos, Apple AE, ATV, Mini or Laptop or PS3. Some use PCs but usually with a streaming device like SB or AE. Two opticals and an analogue covers it for our customers. The problem with USB is that it confines you to a computer in a fast changing market, optical digital gives you a wide choice of sources and I think this is what appeals.

 

Ashley

 

[audioengr]

Tim wrote: "Fortunately, it seems that you're selling all you can build, that those rare audiophiles whose ears, taste and gear are up to the task of hearing Empirical Audio's products are finding you. "

 

That's right. It's like fine wine. If the $5 bottle makes you happy and you are not willing to develop a tase for the good stuff, then we are in a different league. If you are after the very best, we can help you.

 

I'm not interested in being #2 in this game.

 

Steve N.

 

[audioengr]

"I’m afraid that’s the point, a lot of DACs are build like analogue equipment, accept the input as it is. The modern ones recover the clock. I’m inclined to say that if you hear differences between bit identical source or given a source different cables or transmission protocols, it is a badly designed DAC"

 

Well, then there are a LOT of badly designed DAC's out there. I have yet to hear one that is not sensitive to different cables, sources etc.., regardless of what the manufacturer might claim, and I've heard quite a few DAC's in my system. I have modded at least 15 different DAC's, including: Benchmark, Birdland, Electrocompaniet, Meridian, Bremen, Audio Note UK, dAck!1 and 2, BelCanto, Northstar, Assemblage, MSB, Musical Fidelity, EAD, Dodson, Perpetual Technologies and others. I believe I have a bit more experience than any of you on this one.

 

Steve N.

Empirical Audio

 

[audioengr]

Ashley wrote: "We did make a USB only ADM9 but it didn't sell, presumably because the computer is not where the hi fi is."

 

Let me guess: you used a PCM270X USB interface and it supported a max sample rate of 48kHz. If so, then this is the problem. This chip is the bain of USB audio. There are other chips and designs available that sound good enough to challenge even the very best CD players and transports. Most manufacturers select the 270X for their first foray into USB. Bad choice IMO. The reviews reflect this. Several manufacturers have recently changed from the 270X to a good-sounding chip, including PSAudio and BelCanto.

 

I have OEMs that use my USB module in their products, including the new MusicStream DAC from UltraFi (first DAC was the iRoc). Now this is a good-sounding USB DAC.

 

I have to agree that computer audio is still in it's infancy, particularly at the high-end, but mass-marketed devices like the AirPort Express and Sonos are selling like hotcakes.

 

Steve N.

Empirical Audio

 

[davidR]

Steve, do you use a Mac or PC?

 

[tfarney]

"That's right. It's like fine wine. If the $5 bottle makes you happy and you are not willing to develop a tase for the good stuff, then we are in a different league. If you are after the very best, we can help you.

 

I'm not interested in being #2 in this game.

 

Steve N."

 

No, my friend, the music is the wine. You make corks. Or perhaps an additive to the cork that creates the slightest change in the way it breathes. I'm happy for you that you're good at it, but it's not the wine, much less the difference between a $5 bottle and the good stuff.

 

Tim

 

[The Computer Audiophile]

On another note, corky wine is a serious issue :-)

 

[audioengr]

I use mostly XP OS PC's. I like Toshiba laptops. I use Foobar 0.8.3 and unmap the device to bypass kmixer.

 

I ocassionally use Mac too.

 

Steve N.

Empirical Audio

 

[tfarney]

"On another note, corky wine is a serious issue :-)"

 

Where are those rolling smiley faces when you need them?

 

Tim