Format wars?

IIRC, there was talk about comparing different smapling rates of MP3, lossless, and Benchmark DAC output. Anything come of this?

Nope, we never got a chance to do it.... we were waiting for Tom's CD player to warm up... 4 days later, it was time to pack up

The Fire hose of a power cord was hogging all the juice Tom needed to get the CD player warmed up. We'll have 10 days next year to let him get it warm.

ray

Damn, I was really interested in that test. Logic tells me that if you play everything through the same DAC, the digital source shouldn't matter (as long as it's lossless), but I wanted verification.

Yes, I'd like to hear the comparison too! I've also hoped we'd do some cable listening too. I've taken cables two years in a row and haven't hooked a one up.

Bill, while digital sources are ultimately similar sonically, they do differ. It's all in the jitter. Look at any of the Stereophile test results for digital sources and you can see a different jitter profile for all of them. Knowing what that profile means to the audio, is of course another matter.

Music is made up of time and that's what jitter is. The reclocking devices of course help. Kind of like a cruise control on a car...just a little faster hopefully.

Well, I've never gotten to fully understand the issue of jitter. It seems to my simple mind that if you get the bits off of the media perfectly and put them in a memory buffer that feeds a DAC, all of the artifacts of the transport are gone. If there is jitter, it is introduced by the DAC, and should show up the same from all inputs.

radioeng2, what do you use?

Thanks again,

Maybe I should elaborate fuller, in that I have a little less than 15 minutes prior to the debate. I rip all my software (CDs and vinyl) to a hard disk on my computer. Once on my computer, it can be read by software that drives my USB DAC. iTunes reads the disk. All disk I/O on computers is buffered into real memory then the requesting device is told where it is and how long it is, and the device then reads the data into its buffers and processes it. In the case of a DAC, it produces analog signals, and the only place where jitter can be introduced is in that process, in that any transport jitter was lost in the perfect ripping, and any jitter form the hard disk was buffered away. Everything between those two activities and the DAC is software, which could introduce timing errors, but would be corrected if so. Moreover, computer clocks operate in the megahertz range, so their handling of relatively low frequency signals should be pretty good.

This is my third attempt to post a reply. Don'y know what is wrong but let's see if it works this time.

Actually BillD you have, in your follow up, pretty much said it all. So I'm with you.

I guess I just kind of get a chill when it starts sounding like digital is a magic silver bullet that bypasses all problems. The perfect sound forever...it just keeps getting better!!!

How is that...well several areas. Jitter reduction is a big part of it. Also, the 24/96 players are a nice step up. Cheaper 24/96 often sound better than very expensive decks of just a few years ago. You can also clearly hear the in the K2 process(and other names on diff generations) that it's better...even at 44.1/16. And when you read what they do, it's all about a super clean master clock to all the devices in the production chain. Over and over, it comes back to that devil in the details.

Sometimes I feel like starting a list of the vocabulary differences in the distortions of digital versus the lingo of analog issues. I think it could be long...and interesting. The simplified list pretty much comes down to those common ones, the obvious issues with LP playback and digital playback. But all of it grinds down to how much do you enjoy it! How long do you listen? Do you turn it up or down as you go along? Do you find yourself cutting off songs and going to the next or do you listen to cut after cut from the same artist without changing and don't want to go to bed!

Taz, I've used a Pioneer Elite PD-65 player for years. I'd like to do something newer at some point, but it's all a money issue. The stable platter design was pointed exactly towards the digital part and their belief in the fact it does make a difference at that stage. It was good enough to be the basis for some pretty expensive decks. I've also, while working at some speaker design projects, have used the digital out into a Behringer sample rate converter and then the DCX crossover. Like Bill, I've ripped into a computer several thousand cuts headed towards computer playback. My goal is the computer in the back room and remote the KB, mouse and screen to the sound room. Run the audio digitally and D/A at the preamp. I've got everything to do it, just haven't had time to set it up and play with it. By the way, I've done it all in linear, don't need no stinkin' bit rate reduction.

BTW...speaking of ripping, what about the rippers that focus on rereading and comparing the data to get it closer to the same as the original info. Doesn't that suggest that a lot of rips come up with different data than the original? Similarly, I've played with a program that reads a burned disk and reports statistics on errors! Woah...you should see how wildly different they are. I bought a batch of the black CD's since it was reported that they were sonically better. Well, in the level of errors, they were probably 10 times worse than the normal silver discs I already had!

Bill, I'd be interested in how your using the computer in your audio system. Quiet power supply, boxed to lower noise or did you remote it? Do you like the result? I can't comment to much more on how much the method your using gets past the issues.

Oh...I can tell you that the owner of the largest and most known pro audio processing company, told us just this year, that the USB interface is flawed. I can't think right now of the chip manufacturer name, one of the big known ones. He said the chip used in the interface and designed by HP I think, had an inherent flaw in the high frequencies. Sounded like he might have been saying phase shift..but that part is my words. They ran into the issue when complaints come in that the originating machines for web streams, using their processor, didn't sound right. It was eventually tracked to those that were using the USB to input audio. The newer Benchmark USB may have found a way past it and I'd think they did judging by their history and reputation, but I'd still be suspicious of it in all cases from what we were told.

Great topic!!

Well, I know that there are "errors" that are detected and/or corrected through processing in most if not all CD players, but I think that's not the real issue of overall sound. You might get a glitch that will make your CD player hiccup, like a big ass pop on vinyl, but that usually doesn't affect the overall performance.

I will admit that my computer isn't the quietest beast on the block. I use a wireless LAN to transport the signal to decoders in two locations in my house. Playback out of my computer is limited to a pair of Realistic Minimus 7s mounted one either side of the credenza on my computer desk or headphones through a USB DAC (E-MU 0202). It has 24/192 DACs.

In the digital domain, everything has to be bit perfect. You can't drop a bit in a program and expect it to execute. We load all of our software onto our machines via CDs, so the mechanism is extremely reliable in getting things bit perfect. If you notice when you're ripping music, sometimes you'll see it slow down. That's because the comparator got an error and the software is reading an re-reading to make sure it gets the read correct. I know iTunes will fail if it can't get it correct.

So, back to my original premise, if you are using conventional computer techniques, it seems to me that the only thing that is going to affect the sound are components converting the binary to the analog domain or components in the signal chain after that conversion.

......I bought a batch of the black CD's since it was reported that they were sonically better. Well, in the level of errors, they were probably 10 times worse than the normal silver discs I already had!......

Yes, those 'audio quality' black discs are like sweepings off the warehouse floor. They are discs that wouldn't make the quality cut for recording DATA, but who's errors can be masked by the CRC error correction in AUDIO.
Someone figured out that rather than dispose of them, they could sell them off

...... it seems to me that the only thing that is going to affect the sound are components converting the binary to the analog domain or components in the signal chain after that conversion.

Or the equipment used to lay it down into bits in the first place

Yes, I'd like to hear the comparison too! I've also hoped we'd do some cable listening too. I've taken cables two years in a row and haven't hooked a one up.

Bill, while digital sources are ultimately similar sonically, they do differ. It's all in the jitter. Look at any of the Stereophile test results for digital sources and you can see a different jitter profile for all of them. Knowing what that profile means to the audio, is of course another matter.

Music is made up of time and that's what jitter is. The reclocking devices of course help. Kind of like a cruise control on a car...just a little faster hopefully.

Mark, if I'd known you brought cables (you never mentioned) we could have done a/b comparisons on my system....damn!

Once in a while, Stereophile does in depth, the larger picture, kind of articles. One long ago stuck with me and is pretty good reading. I've went back to it several times over the years to re-read it.

http://www.stereophile.com/reference/590jitter/index.html

Notice, that's its from 1990, meaning pretty early in the CD years. The knowledge of what's going on with digital and the ability to measure the jitter have come a long way since this article. Please take the time to read it!!

Another good one, from 4 years later, goes into a few more areas and shows they'd learned more...

http://www.stereophile.com/features/827/index.html


This article does a pretty good job of going through the CD manufacturing process including pictures. Lots of fun parts to these articles, like this...

"The raw data recovered from a CD are never identical to the data recorded on the disc. The CD system introduces data errors and dropouts through contamination, scratches, pinholes, and the other manufacturing defects described."


BTW...Both of these articles are written by Robert Harley, now Editor of The Absolute Sound. He has a really good book that covers a ton of the audio topics and is highly recommended reading! I've met him, and visited with him, at a show. Very nice, rather soft spoken, well informed and experienced guy. Think how neat it would be to get somebody like him to come to Carverfest '09?? He could probably do a great job of bridging the gap between the fundamental technical side and the relationship to the sonic part of equipment...(and cables). Wouldn't that be cool??!!!