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In Reply to: RE: Just to confirm - in your experience, the changes (drivers, players etc.) on computer side.... posted by Tony Lauck on September 04, 2014 at 17:15:21
"Unfortunately, the computer creates a huge amount of noise."
How much is "huge" and how has it been measured?
"If they had a standard "bad" transport that was very noisy while still bit perfect"
Maybe it's hard to find components that are both bit perfect and noisy?
Would it be easier to come up with software or hardware that injects noise into a system so reviewers and engineers can judge how well downstream components deal with the noise?
JE
Follow Ups:
"'Unfortunately, the computer creates a huge amount of noise.'
How much is "huge" and how has it been measured?"
Huge, as in my wife complained about my computer(s). She picked up the interference on her AM radio. Her radio was running on batteries, so the noise didn't have benefit of any wires at all, no SPDIF, USB, power cords, etc... If you look on the back of computerized devices you will see little stickers with FCC numbers, CE numbers, etc... These are all certifications that these devices emit an "acceptable" level of interference, where acceptable is a political compromise between powerful players, in this case TV broadcasters and FM broadcasters vs. computer manufacturers. AM radio wasn't so politically connected at the time these regulations came into effect a few decades ago. Because of the technical characteristics of audio, there were no standards associated with audio. It has always been the case that audio equipment has been able to defend itself against interference, and it is the responsibility of audio equipment manufacturers to do so. (Following a long line of cheapness, they seldom did.) In the 1950's as a teenage radio ham my transmitter caused interference with nearby record players and I helped solve the resulting problems as a good neighbor, not because I was legally required to do so.
The same situation applies where the interference comes over power wiring and there are filters that can be applied. (Also described in the 1957 edition of the Radio Amateur's Handbook.) The situation also applies to signal wiring (SPDIF or USB). Here the equipment to measure this is available, but it is very expensive and a major investment for boutique manufacturers.
If you pick up an AM radio and set it near your computer (or CD player) you will get an idea of what is going on. You will hear different patterns of noise when the computer is idle and when it is active, e.g. playing music. You will hear these patterns change when using different players or adjusting buffer sizes. All of this interference affects the analog equipment in a DAC and downstream amplifiers to some extent or other, depending on how much rejection the audio equipment has for spurious signals.
"If they had a standard "bad" transport that was very noisy while still bit perfect"
A cheap computer system might do just fine. :-) But a better way of testing would be to take a fairly good transport and pass the output signal through a purpose built box that deliberately adds various amounts, types, and frequency ranges of interfering noise. There are specs for how noisy an input signal is allowed to be and still be a "legal" signal that an SPDIF or USB receiver must accept as "bit perfect". This means there is a limit on how bad the noise can be on the signal wires, otherwise the system won't work without clicks, pops or dropouts. This limit puts a ceiling on how much noise the filtering circuit must be able to reject. The amount of rejection depends on the audio quality level desired. There are serious cost issues here, because the amount of rejection is limited by the number of isolation stages, power supplies, ground isolation, physical shielding, etc...
There are also differences of opinion as to how much residual noise is actually audible. These differences arise for various reasons, but the most controversial reason is probably that some listeners are willfully deaf while some other listeners willfully imagine non-existent differences. Hopefully, there will be few of either camp that will reply to this post. :-)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Tony,
What is you feeling regarding using proper materials to reduce interference in our PCs? We are really looking for lower noise than the manufactures have to provide. It is actually not too difficult to do.
regards
Bob
I would move the PC away from the other audio equipment an put it on a separate power circuit or otherwise electrically isolated. I would isolate the DAC from the computer through various devices (such as external USB converter boxes or reclockers) unless the DAC has done this well. This will provide an extra stage of isolation between the noisy computer and the DAC if the DAC lacks this stage internally. Ditto, with providing USB power to the DAC rather than taking it out of the computer.
These are all things for which there are rational explanations of how they work, but of course the people peddling them may have other motives and what you get may not be what you hoped for. There are other approaches as well, which are the equivalent of adding tassels to oriental rugs to "ward off the evil eye". These may also be perceived to work... I have a bunch of oriental rugs and I am not about to start cutting off the tassels to see what happens. Perhaps I am too superstitious. (I have a fair amount of Irish blood.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
It is rational to isolate the computer and the dac, but not components within a computer that generate massive noise which affect each other, since those who understand computers don't think this matters
Very 'rational' line of reasoning indeed!
Fences cost money. You can save more money if you fence off the valuable stuff, rather then fencing off your entire yard. You may save enough money to put up several levels of fencing around the valuable stuff, maybe even pay for a moat and a barbed wire fence and guard towers.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
for a computer audio 'expert' who is posting about reasoning and rationality.
Edits: 09/10/14
I think that I recall someone using it here, inside the case.....
Speculating, - (obviously), - something to try after pulling power supplies, and/or engaging a "better" USB bus, perhaps.
Cheers,
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
I've used it in my old pc. Seemed to run faster but i wasn't using it much for audio. video did improve: better colors n black level.
scientific explanations, (spacecraft use), regarding that.
When I was checking out the Zanden CD player a few years ago, the owner pulled the case, and ton of it flew out as if it was spring loaded. Thought that it was OTT
Cheers
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Yes, there is allot of good info on the Jplay forum.
regards
Bob
"Huge, as in my wife complained about my computer(s)."
So your claim has never been quantified? How about we turn the microscope to my "PC" system. The one Bob_C called a "Yugo," though I prefer to think of it as a "Miata." Let's agree about two things with regards to the Xonar Essence sound cards: One, they are not "next to" or "near" PCs, they are positioned inside PCs, about as toxic an environment as you can get. Two, at roughly US$200 they are modestly priced, indeed, one could say trivially priced, according to the standards of high end audio. At less than the cost of a meter of "audiophile" Ethernet cable, surely they must have negligible noise rejection.
We often bemoan the inability of the average audiophile to measure their gear. Normally, the conversation stops there. However, in this case, JA at Stereophile has thoughtfully measured the Xonar Essence sound card, while it was inside of a PC! I've linked to this before, but I'll do it again. My question is, looking at JA's measurements, where is the distortion and noise I'm supposed to be worried about?
"If they had a standard "bad" transport that was very noisy while still bit perfect"
Now wait a minute. I was quoting you, and now you are quoting you back to me as if it was something I said?
"A cheap computer system might do just fine. :-)" Or perhaps not? If the measured noise of a sound card inside of a PC is still more than -100dB down how meaningful of a tool might it be?
"There are also differences of opinion as to how much residual noise is actually audible." There sure are! I keep touting the Audio Diffmaker as an example of how hard it is to hear brass bands way down in the mix, much less noise, but no one in this forum seems to have the courage to even listen to it, instead insisting that they can hear, and be annoyed by, noise more than -100dB down. Since I freely admit to not being worried about noise at those levels I guess you would put me in the "willfully deaf" category.
JE
Of course all the noise that I discussed has been quantified. That should be obvious from my post. If noise couldn't be quantified there wouldn't be national standards for legal amounts and there wouldn't be specifications for acceptable waveforms in standards documents for interfaces such as SPDIF and USB.
I won't comment on quotes that are done without understanding or with the possible intent to confuse.
I am interested in engineering standards and perceptual excellence. "Standards" based on pricing relate to business and marketing, which are generally subjects that (no longer) interest me, except where an inferior product is grossly over priced. (As appears to be the case with some audiophile USB cables that don't meet USB specifications, but unfortunately the test gear needed to verify this is extremely expensive and the manufacturer who has the necessary data is, understandably, keeping mum.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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