Do equipment stands have an impact on electronics?

Obviously its not a big deal.  if it were it would have been made apparent by now.

"accuse of having an agenda." Truth can hurt.

"A common example is the capacitor placed on the reference input to an ADC. The circuit may work fine in the lab, where it isn’t being shaken vigorously. Once it is installed in an environment with vibration, significant errors in the ADC readings might appear. Power supply designers are also aware of the converse piezoelectric effect, where the ripple voltage across the capacitor causes it to “sing” or vibrate."

You owe atmasphere $100, Ethan. Pay up or shut up.

Dave

Geofkait alone going on and on and fear mongering about esoteric theoretical things does not make them a big deal. Just because something can happen does not mean it will. He needs some disciples to help spread his gospel. Also maybe do something besides talk and repackage others stuff to try to sell here.

Not impressed with Ethan’s attitude methods conclusions or approach either.

Guess that leaves us where? No better or worse off than when we started.

At least Atmasphere, though operating on/offering a different paradigm than most, presents useful information in a reasonable manner with no condescending attitude normally so people can decide and digest on their own to what extent it really matters to them. Plus he has years of experience actually testing out and making things that clearly back up what he says whereas Ethan is still measuring away trying to figure out how things really work and seems bent on convincing others that he has figured it all out better than all the rest already somehow. He too could use a few disciples to help spread the gospel. Atmasphere has plenty of those.

Ralph, I can’t tell if you’re being disingenuous or you really believe what you write. For now I’ll give you the benefit of the doubt and address your points. You’re in quotes below, and I’m not:

"When you say ’0.01’ are you referring to THD? When one looks at digital specs, one is lucky to find the distortion spec listed at all; if it is its usually in terms of db and at that also as a composite figure representing THD and noise together (which seems a reasonable way to express the value). However its the inharmonic distortions that are the larger amount of distortion that has shown up in a lot of digital gear over time, but that number is not included in the spec, in fact I don’t see it on websites anywhere."

I was quoting typical specs. When I assess gear I often use the FFT display in Sound Forge because it shows all artifacts. I’ve done this dozens of times, and FFT screens are included in my two AES videos and in my Audio Expert book. If there was some mysterious type of "inharmonic" distortion, other than IMD or jitter or aliasing which are all known and understood, I’d have seen it by now in an FFT. There is no such thing. If you believe otherwise, please post an FFT showing that distortion, and explain how you created it.

The GIF linked below displays a series of FFT screen caps showing the THD and IMD and spectral noise of an original Wave file, a copy played out and back in through a 16 year old Delta 66 sound card, and again out and in through a $25 SoundBlaster X-Fi sound card:

http://www.ethanwiner.com/misc-content/sound_card_distortion_corrected.gif

I generated the source file in Sound Forge, so I imagine it’s as clean as a 16-bit digital source can be. The record level meters said -1 for both sound cards for all frequencies:

20 Hz
1 KHz
10 KHz
19 + 20 KHz

Clearly the Delta 66 is extremely clean even when recorded at -1 dB. This proves beyond all doubt that a halfway decent sound card - even a very old one - does not generate "inharmonic distortions" at a level that’s even audible let alone intrusive. And before you claim that people can hear artifacts that are 110 dB down, this section of my AES Audio myths video plays a pair of recordings made simultaneously through the same $25 SoundBlaster sound card and a very high-end Apogee converter:

http://www.youtube.com/watch?v=BYTlN6wjcvQ&t=41m15s

Even with the higher level of artifacts in the SB card, the sound quality is still very similar to an expensive converter. And before you accuse YouTube compressed audio of masking the differences, here are the original Wave files:

http://ethanwiner.com/aes/sound_cards1.wav
http://ethanwiner.com/aes/sound_cards2.wav

"Since the collection of data from a CD is an analog process, its reasonable to assume that reducing vibration in the transport will improve data recovery. Its not uncommon to see damping applied to high end CD transports."

Wow, talk about circular logic! First, the makers of "high end" CD players do whatever they think is needed to convince people to pay handsomely for their stuff. That they "isolate" their transports means nothing. They probably claim to use some BS over-designed power supply too. More important, if you believe normal amounts of vibration can affect audio quality, why don’t you test it for yourself? I’ve done that, which is why I know isolation for CD players is BS. It’s not a difficult test! If you design audio gear, surely you have a sine wave generator, a CD burner, and a way to record the player’s output as you shake it around while playing your test tone CD. Or just watch the output on a ’scope as you shake it. Or just listen. Sheesh!

If there was some mysterious type of "inharmonic" distortion, other than IMD or jitter or aliasing which are all known and understood, I’d have seen it by now in an FFT. There is no such thing. If you believe otherwise, please post an FFT showing that distortion, and explain how you created it.

Thanks for your explanation. So the specs you quote are from your own measurement?

Inharmonic distortion is a form of IMD, in this case related to the scan frequency. Its called that as the distortions are not related to harmonics of fundamentals, and differs from regular IMD as it can occur with only a single tone being recorded. IME, its most likely to show up on the record side, and can’t be detected with static tones. You have to use an analog sweep generator (using static tones, or tones generated digitally allows the technician to be unaware that there might be a problem). Set to sweep 20-20KHz, record at just below 0VU and in playback, listen for the ’birdies’ (this is radio parlance for subtones and supertones that vary with the changing frequency of the sweep tone; obviously you will want to set the speed of the sweep to a slow rate so its easier to experience the birdies). It might be a record-only artifact; the problem is you have to play back the sound file at some point and I’ve not investigated the issue enough to ascertain how much of a role the playback systems play. This problem seems to have improved over time- it was horrendous only 15 years ago!

First, the makers of "high end" CD players do whatever they think is needed to convince people to pay handsomely for their stuff. That they "isolate" their transports means nothing. They probably claim to use some BS over-designed power supply too. More important, if you believe normal amounts of vibration can affect audio quality, why don’t you test it for yourself? I’ve done that, which is why I know isolation for CD players is BS. It’s not a difficult test! If you design audio gear, surely you have a sine wave generator, a CD burner, and a way to record the player’s output as you shake it around while playing your test tone CD. Or just watch the output on a ’scope as you shake it. Or just listen. Sheesh!

I do design audio gear, but never gotten to the point where I take digital seriously. I show with digital gear at shows of course, but if I have the same track on LP its always a very easy thing to demonstrate how much better the LP sounds than the digital. The worst system we’ve used at shows was a Tascam DV-50; Tascam is a major supplier of CD transports so you would think their machine would be pretty competent, but I found it irritating enough that usually I could not play an entire track with it (and I have found this pretty repeatable with other examples so I know it was not due to a malfunction). By contrast I find the less expensive Oppo players to be more musical.

The way I see it, if digital is working properly you won’t hear any difference from one machine to another, but we hear differences all the time, which says that the digital is falling well short of the ideal.

The most expensive setup we’ve shown with was also the best (although a close runners up is much more affordable!) by a country mile over any setup I’ve heard anywhere (I have customers with the dcs setups, which have been a benchmark in high end for a long time). When the designer was in the room playing a cut, I asked him if he would like to hear the same thing on LP; he said yes and upon hearing the difference, turned to me and said "digital has such a long ways to go". Its that pragmatic approach on his part which I credit for his gear being one of the very best I’ve seen.

Now I should make a distinction here- if the sound file is stored on a hard drive or the like I find it robust. It should not be that when you change a CD transport that the sound should change but it does. That simply says to me that CD playback is variable, and is a proven topic that has endured for decades on the web. In a nutshell, its not robust while hard drive performance is. This is why there are programs like ’CD Paranoia’ (an older bit of software for Linux) because Redbook simply does not allow for complete data recovery.

Its very easy to show that vibration can affect a CD transport. Just tapping some machines can cause the CD to drop out or stop playing altogether! So it would appear that reducing vibration, such as on a platform, could have an effect. Personally I feel that the sooner we get rid of the CD format, the better.