Flame me for saying this, but I don't think I have much of an issue with jitter. All of my ripping is done with cdparanoia, and all of my playback is from a nfs share. The system definitely doesn't have any problems keeping its buffers fed. 1GHz P3 w/384M to play with.

I'd like to learn more about the implications of bit depth and sample rate as applied to audio streams, though. Got a reference on that? I'd think the resampling shouldn't be /too/ much of an issue, given that EAX is nothing but a SIMD subprocessor. I'd imagine the steriods shipped with Audigy improve on its ability to crunch numbers in realtime.

If I was going to buy another card, I'd be looking for a 24/96 with an optical output, and if possible the ability to output 5.1 discrete via digital. If it was a pure music jukebox I'd probably go for that Echo, but I'm also playing DVD movies with it, and thanks to all of my other home A/V shit I don't have the stereo deck inputs for a gaggle of sound cards.

Said A/V shit includes an RCA satellite receiver, 4head hifi vcr (yecch), and an all-in-wonder Radeon. The computer is both a source and a recording device.

On Tue, 25 Sep 2001, John van Ommen wrote:

I'm glad to hear that MAD sounds good on your PC. You stated that you were closer to audio nirvana because you had bypassed the DACs in your SB Live. While improving DACs is certainly a good thing, note that this doesn't eliminate what is potentially the biggest problem with digital audio, jitter.

A definition of jitter: http://www.feurio.com/English/faq/faq_vocable_jitter.shtml

I have a box that re-clocks the digital signal, a Monarchy Audio Digital Interface Processor. This seems to restore the pace to music, and also smooths out the treble. I used to use it with my desktop PC, but found that their was a greater improvement when I hooked it up to my laptop. This is primarily because my computer's audio colletions is mostly on my 60gig hard drive, whereas I listen to MP3 CDs on my laptop almost exclusively. And of course, a hard drive would have *much* lower jitter than a CD-ROM, because it's a much more stable mechanism.

One of the big problems with the SB Live is that it outputs a 16bit, 48khz signal. So it's doing some really weird resampling in real time, even with 44.1khz audio. I used to use a SB Live, but I found that a cheap $40 Maxi Sound Fortissimo sounded better when using the SPDIF output. The Fortissimo lasted about a year, but I replaced it four months ago with a Echo Mia, which has 24/96 output. For $150, the Echo Mia sounds stellar. Even without a outboard DAC or any kind of re-clocking or upsampling, it sounds excellent. In some respects, I find that MP3s played on the 24bit Echo Mia actually sound superior to CDs played on my Harmon Kardon CD player. Must have something to do with the low jitter and the exceptional DACs in the MIA. Amplification is tubes.

Bottom line is that your MAD setup may sound good now, but you'd be amazed how much better it CAN sound.

John

P.S. If I can find a few minutes, I'm going to try upsampling a CD to 24/96 bit wavs using Cool Edit 2000, compress the wavs, then play the 24/96 MP3s through the MIA. That should really give my CDs a run for their money. Another thought is to do something similar with the audio track of a DVD.

-----Original Message----- From: mad-user-admin@lists.mars.org [mailto:mad-user-admin@lists.mars.org]On Behalf Of Kevin Cody Jr Sent: Sunday, September 23, 2001 1:02 PM To: mad-user@lists.mars.org Subject: [mad-user] Howdy

Mad + mpg321 just became my mp3 playback tool of choice based on output quality alone.

FYI, my setup is a dual-boot RH7.1/Win98, with an SB Live and the optical i/o daughtercard, feeding into a JVC RX-1028V A/V deck. Under Linux that optical S/PDIF output seems to be a nearly-transparent passthrough, meaning it isn't mixed. I'm not sure if it's the card or ALSA doing the sample rate corrections. Probably the card.

This has yielded what I believe is the cleanest possible pathway for digital audio, because it's using the much higher quality DA's in the JVC stereo unit. I believe that for a digital recording, the only point of significant signal loss is the MP3 encoding and decoding. Thanks to MAD, the vast majority of that is now the encoder.

Which leads me to the reason for posting: this implies that much of the perceived fidelity loss of MP3's involves flaws in soundcard DA's getting tickled by something in the MP3 algorithms.

I'm available for whatever testing anyone can come up with. Keep up the good work!

• Kevin Cody Jr