CDs vs Hard Drive shootout

I'll always keep a reference CD player for times when I really want to LISTEN, but for convenience I've been considering a cd jukebox (sony etc). However, having all my cd's on a hard drive would be even more convenient.

Speak to me not of mp3, I'd only do it with as close as I could get to EXACT copy of cd original with this. Then for playback feed SPDIF output to the DAC.

1. What audiophile considerations are involved in storing an exact copy of a cd on hard drive? (jitter?)

2. Once I have exact copy, what are the hurdles for accurate playback (assuming digital output to external DAC)? (assumption is that since hard drive data rate is xx times cd read rate, jitter transport stability etc would not be an issue.)

Welcome any comments, and appreciate any links to more info.

For a cost effective interface from your computer to a DAC and music data file management, check out :

FYI- if there's jitter present in the original recording,
an "Exact copy" and the hard drive data rate will do nothing to eliminated it. All you can go is prevent additional jitter from being added.

Finally, if you haven't heard the difference a good transport can make, you haven't heard a good transport.
I would highly recommend listening to a Linn KIVOR.

Checkout Real Rhapsody online. I can't tell you what the file is to my USB port (fed digitally to my Meridian processor via coax), but I know when I burn a disk from there it is said to be in the same format as a store bought CD. For ~$10/month I can listen to a variety of music and do research on different artists, etc.

Other than an occasional delay blip while I'm playing online chess, it works like an online digital jukebox. Sounds pretty good on my system (Meridian/Proceed/Aerial).

No, I do not work for the company!
I have used EAC to rip my CD collection to a hard drive for background music. While I've also used LAME to compress the material, with the price of 1/2 TB drives now coming into the range of reason, I'm considering going back and redoing the lot uncompressed. Since I've got an ethernet network in my house, I found a neat device by Linksys that has an ethernet jack on one end, a couple USB 2.0 ports on the other, and essentially allows use of USB hard drives as Network Attached Storage. I use that in conjunction with Audiotrons to play back the music at various stereos in the house.

Given the effort of ripping one's CD collection, you should make some provision for backing everything up--you chew up an awful lot of space with .wav files, but you should really be thinking of multiplying req'd storage by 2.

One other problem with .wav files is that there isn't any file tagging like with .mp3s, so one of the big benefits (in my mind) of computer audio goes away (ability to view/retrieve by track/artist/genre/album). There are some other formats like Ogg Vorbis, FLAC, AAC, and others that use lossless compression and allow tagging, but I haven't really gone too far in examining how I do playback with those over the network. I don't think, for example, they are supported by my audiotrons.

In terms of hardware, I use audiotrons (turtle beach) for remote stereos. Doesn't look too bad, has a digital out, and doesn't--like the CD30 and Slimp3 and others--require server push (having a computer feed the devices via e/net). The ATs are smart enough to catalog audio files in public directories anywhere on a local net, and pull the files as needed.

For playback off the computer located near the stereo, I use an Edirol UA-1D, which is a USB to coax digital device that retails for about $80. I run that into a Theta DAC, and into the stereo. Sounds remarkably good for mp3 technology, and probably would sound even better with wavs. My impression is that the optimum solution is really going with a pro digital audio card by someone like RME; they usually have AES/EBU XLR outputs you could use to feed a DAC and probably have better clocking hardware in them. The problem with those is that they are usually multichannel, so you are paying a fair premium for a bunch of digital I/O that you probably don't need.

Good luck!
You might want to look into the archives of this Yahoo group. Am not sure if you need to join to view prior posts.

As for Kana813's comment on jitter, it seems possible that if the jitter is introduced during the CD manufacturing that ripping the CD to the hard drive could improve it. For instance, if it is manufactured on warped media, or someone burns a CD at 40X, then the data is there, just not written to disk in an optimal manner. Reading the data to the hard drive may remove any inconsistancies due to that process. Just a thought.
"I'll always keep a reference CD player for times when I really want to LISTEN"

Throw away the cd player! If you get a chance to hear a hard disc system like the VRS, you will find out that you don't need a cd's that good! Certainly better than my Sony 777SACD player. VRS says you can't use an outboard dac...Gordon Rankin at Wavelength says USB solves jitter issues w/ outboard dacs. Take your pick. I just picked up a used iBook and am waiting on an outboard USB dac to be built. We shall see.

My comment on jitter pertain to jiiter present in the A/D
conversion during recording process. You can rip, burn and copy all you want and it'll will still be there.

IMO- a CD pressed on warped media may be hard to read, but it not adding jitter like the A/D process. CD pressed from worn out/down masters are more of a problem.

The other main cause of jitter is power supply noise. The power supplies used in computers are cheap and noisy(I'm talking a fan noise), and should be isolated from the audio system.

If you want to control jitter from hard drives devises look for a used Genesis Digital Lens or the Apogee Big Ben.

Finally, I'll put my money on the sound quality of hi end
transport, over the cheap drives inside of computer.
I don't see how fan noise from power supply can cause timing errors in the digital stream (jitter).
Sidssp- Sorry, I meant to say- "I'm not talking about fan noise." The noise I'm referring to is ripple noise from the SMPS units used in most computers. I'll have to start
using the preview feature.
thanks all - good head start . . .
I must admit that jitter does confuse me. There are many possible causes for it and I'm not sure why re-clocking and buffering doesn't correct many of them. But I don't expect to understand everything that goes into making things sound great.

I happened on an article about the EAC program that discusses the type of jitter that can occur during CD manufacturing. The author mentions how this can be corrected by ripping such CDs to disk and burning the resulting image to a CD.

I'm not trying to refute the other jitter inducing causes mentioned by Kana813. But this article does agree with my thought that some of the jitter factors could be improved by reburning the data. Maybe it's wrong, but it's on track with my thinking.
From the article:

"In practice, it is the lack of crisp pit formation in a stamped CD that causes most of the problems. If a clock 'tick' prompts the laser to read the next sample and the wall of that pit isn't interpreted as a wall, the sample isn't misread but read just a little too late. Every transition from pit to flat and flat to pit becomes read as a digital 1. For a purely digital likeness, time delays don't pose any problems since the 1 is properly extracted. During playback, however, you will notice a peculiar harshness often associated with the medium. These offsets in time are called jitter."

Yes- some jitter or read errors from a worn stamper can be improved by ripping with EAC. But once again jitter present during the the Analog to Digital process of the the recording can't not be corrected.

FYI- the new Auric Illumunator will also help smooth out
the digital glare on these CD.
Kana813 wrote:
"Yes- some jitter or read errors from a worn stamper can be improved by ripping with EAC. But once again jitter present during the the Analog to Digital process of the the recording can't not be corrected."

Not true. When the data is read off CD's using a CDROM and EAC, this is done at very high speed. The data jitter is a non-issue. Bits are bits and the checksum shows that all of the data was read correctly - all of the "pits" were recognized properly.
audioengr -

so by saying data jitter is a non-issue, assuming you mean both jitter introduced during manufacturing AND during playback (by transport err etc - we'll keep DAC issues separate).

What other objective mechanical advantages might hard drive playback have over a good transport (or vice versa)? Or is jitter the main consideration??
ps. Mmrog - excellent article in your 8/28 post - thanks!!