[Gatticus]

Quote:

Originally Posted by audioengr /img/forum/go_quote.gif No. I2S will be better anyway. It is the native interface for the D/A chip. Steve N.

Wow, I link to your article and you show up. Cool.

So, do you think I should continue using my EMU 0404 USB over SPDIF or go back to the USB interface?

 

[jlingo]

Quote:

Originally Posted by Gatticus /img/forum/go_quote.gif I read an article about some guy who was a symphony musician and he claimed his $10,000 speaker cables made a huge difference to the sound quality of his stereo. He was definately placebo'd. Poor sucker.

No it's not placebo, you see you need the whole supporting system, not just the cable. If you try to play $10,000 cable on an iPOD, that just won't work!! Or try to hook up GS1000 directly on an iPOD just aint gonna work! You need better source you need better DAC.

Many better headphones or speakers are very picky with the source, the amps, cables, positions, room, diffusor and so on. You have to experience them for yourself.

 

[fulltruth]

How can USB sound worse than SPDIF? I thought USB had error correction while SPDIF does not?

 

[bigshot]

Ever since even reasonably priced audio equipment reached a level of quality where their performance specs (freq response, wow flutter, distortion, dynamic range, etc.) became basically the same as the most expensive equipment of the past, high end stereo salesmen have been searching for a NEW spec to show that their particular model is better than the ones you can buy for a couple hundred bucks at Circuit City. Jitter is what they came up with. Jitter is a concept designed to separate obsessive equipment fetishists from their money. It is totally inaudible at the minute levels which it occurs in even the cheapest CD players.

See ya
Steve

 

[fulltruth]

Would you mind posting some info about your rig, bigshot?

 

[audioengr]

Quote:

Originally Posted by Gatticus /img/forum/go_quote.gif Wow, I link to your article and you show up. Cool. So, do you think I should continue using my EMU 0404 USB over SPDIF or go back to the USB interface?

Hard to say. The implementation of either can be bad or good. Usually, the USB is better, but this is very dependent on the software that you are using on the computer, the ASIO, the player, the SRC etc....

This is why I licensed a really good USB firmware that eliminates the need for ASIO and delivers bit-perfect output.

Steve N.

 

[audioengr]

Quote:

Originally Posted by fulltruth /img/forum/go_quote.gif How can USB sound worse than SPDIF? I thought USB had error correction while SPDIF does not?

Neither has error correction. USB isochronous has no error correction. Errors typically do not occur on either. It's the jitter that's different.

Steve N.

 

[fulltruth]

I'm pretty new to this topic, but I'm very eager to learn. (I'm a programmer BTW.) What is the distinction between 'errors' and jitter? I will guess that an error is when a bit gets corrupted on the line, while jitter has something to do with the clock(s).

 

[audioengr]

Quote:

Originally Posted by bigshot /img/forum/go_quote.gif Ever since even reasonably priced audio equipment reached a level of quality where their performance specs (freq response, wow flutter, distortion, dynamic range, etc.) became basically the same as the most expensive equipment of the past, high end stereo salesmen have been searching for a NEW spec to show that their particular model is better than the ones you can buy for a couple hundred bucks at Circuit City. Jitter is what they came up with. Jitter is a concept designed to separate obsessive equipment fetishists from their money. It is totally inaudible at the minute levels which it occurs in even the cheapest CD players. See ya Steve

Actually, in addition to jitter, the biggest deficiency in even the most expensive consumer gear is good DYNAMIC or TRANSIENT RESPONSE. This is never properly chararacterized, and the things that achieve it are usually poorly implemented.

And Jitter is a bigger problem than you even know. It is the single biggest problem that makes digital audio fatigueing, and keeps people using vinyl. I have 30 years experience with this and hundreds of customers that will attest to this.

Steve N.

 

[audioengr]

Quote:

Originally Posted by fulltruth /img/forum/go_quote.gif I'm pretty new to this topic, but I'm very eager to learn. (I'm a programmer BTW.) What is the distinction between 'errors' and jitter? I will guess that an error is when a bit gets corrupted on the line, while jitter has something to do with the clock(s).

I wrote at least one white-paper on it:

http://www.positive-feedback.com/Issue14/spdif.htm

http://www.positive-feedback.com/Issue14/spdif.htm

and here are a couple more that I didn't write:

http://www.stereophile.com/reference...er/index1.html

http://www.geocities.com/jonrisch/jitter.htm

Steve N.
Empirical Audio

 

[korben_dallas]

Steve N.

Do you have a suggestion for the best implementation of 5.1 playback on PC? I see some USB DAC's mentioned here but none that can do surround. And another concern of mine is ease of use. It's hard to beat the simplicity of my Audigy 2 --> amplifier --> speakers, hit play in Windows Media Player, and 5.1 is heard.

I ask because I'd like to upgrade to HD DVD / BD and want to be able to get every bit of audio fidelity those discs can offer.

 

[audioengr]

Quote:

Originally Posted by korben_dallas /img/forum/go_quote.gif Steve N. Do you have a suggestion for the best implementation of 5.1 playback on PC? I see some USB DAC's mentioned here but none that can do surround. And another concern of mine is ease of use. It's hard to beat the simplicity of my Audigy 2 --> amplifier --> speakers, hit play in Windows Media Player, and 5.1 is heard. I ask because I'd like to upgrade to HD DVD / BD and want to be able to get every bit of audio fidelity those discs can offer.

I think you probably have the simplest set-up. Options for improvement include:

Mods to the Audigy 2 to improve the clock and outputs.

Off-Ramp Turbo 2 or Freeway 2 (with M-Audio drivers that support AC3) driving a good SS decoder, such as a used Proceed AVP.

Steve N.

 

[Dept_of_Alchemy]

Quote:

Originally Posted by fulltruth /img/forum/go_quote.gif How can USB sound worse than SPDIF? I thought USB had error correction while SPDIF does not?

Can of worms, man.

 

[Maniac]

Quote:

Originally Posted by shriramosu /img/forum/go_quote.gif I understand that one of the main advantages of PC audio over CDP's is reducing/eliminating jitter (others are error correction, ability to upsample, apply cheaper room correction). Specifically with respect to jitter it seems like the higher end devices like Empirical audio's solution, using battery supply, doing DAC separately etc are ways to reduce jitter. My question is what points in the system for PC audio can jitter enter the data stream and how? (starting from say whats high jitter, from a soundcard out, to less using USB to Coax to receiver in, then even less using USB to I2S to DAC) etc. Thanks Shriram

I'm kinda late to this subject, but make no mistake about jitter in PC, the jitter in PC is HUGE... Sometimes SDRAM bus can have around 20% jitter, which might just drive people out of their mind if it occurred on your standard equipment.

Jitter is not that big an issue on PC because the data is not time critical, but it will become critical if clock itself is part of the data.

SPDIF is especially sensitive to jitter due to the fact that the playback clock is embedded into data. Computer itself have masses of different circuits that often operates at extremely high frequency, producing all kind of interference, plus the large switching power. The whole thing is a mess.


One very simple experiment (also a upgrade too) is switching to a higher capacity and better made ATX power supply. The background noise instantly decrease by a significant amount, with detail and transparency increased immensely. that's with an externally powered USB DAC, all it takes from the computer is data and USB presence sense.


If jitter does not matter, then I suppose you won't need a motor with stable 33RPM for vinyl records either, heck jitter matters not, it's bogus, so why should mechanical jitter on record be any different?

 

[Maniac]

Quote:

Originally Posted by cotdt /img/forum/go_quote.gif Use PC -> DAC via I2S connection. It has lower jitter than CD Players. Or even with SPDIF, you can add a clock. However, after looking into the subject I'm not sure how much jitter really matters. Most likely it is the clock noise that is causing the sound degradation, so a less noisy clock would improve sound greatly.

If you isolate the power supply that feeds the clock (if possible, like when using an XO), the noise injected into the system power supply will be much less, it will sound a lot better.

The modded clock benefits a lot from this part of the modification, even if you only use a standard XO instead of those expensive XOs (those good ones does help even better, but not all improvements are from the XO itself).