[raylpc]

Quote:

Originally Posted by stevesurf This is a comprehensive article, yet one that has not considered all issues. Yes, I understand the equality of a noise-free PC system for playback, but my issue is that PCs are not necessarily reading the CDs original data as accurately and jitter-free as a high-end transport! If you are not timing your CD drive correctly, you are, quite simply NOT getting all the audio information.

I believe Exact Audio Copy (EAC) is able to read the CDs bit-perfect and save to the harddisk without jitters. It's true that the PC CD drives are not as good as those expensive transports. But think about it, somethings are only available to the PC CD drives at ripping but not to the expensive transports at playback - the ability to read the bits for many time and use the error correction codes to ensure the bits are correct. So I believe a properly done EAC rip is jitter-free.

There's jitter when getting the bits from the computer to the squeezebox tho. That's why squeezeboxes employ crystal oscillators as well to time the DACs.

About the interference, nspindel is right, just go and buy a 5GHz cordless phone.

 

[audioengr]

This article may shed some more light on this question:
http://www.positive-feedback.com/Issue22/nugent.htm

 

[Tim D]

Getting a clean digital out from a CD transport is typically easier. For computers, you can again go optical or wi-fi. Other methods are complicated with ground loop/noise, but these are sometimes avoidable.

Besides electrical noise, there is acoustic noise of the computer which is typically much worse than a CD transport. My Dell laptop is on the quiet side of the spectrum and I have it configured to turn off its fan now and then depending on temperature, but it is still overall much more noisy than an absolutely quiet transport. Apple iBooks however are pretty much equal to very quiet transports as they operate mostly fanless unless heavy duty processing.

Finally there is jitter, and it is typically generalized that jitter is much worse with computer setups, but not often qualified. However if you have a ground loop/ noise issue...than I'm pretty sure the jitter is much worse (and ground loops in computer setups are common and often go unnoticed if its not the most obvious ground hum). Overall there is not a whole lot of objective data in regards to jitter measurements for varying PC audio interfaces. But I am guessing it ranges from very bad, to quite acceptable. To be honest I haven't found much good objective data in overall sound performance alone much less the jitter component for computers and its bogged down by test setups or people oblivious to ground loop problems (I've seen 'expert' computer hardware reviewers publish reviews that spit out RMAA reports with ground loops/hash in them). Instead the 'Creative' marketing bandwagon focuses purely on 'bits' and SN ratio's.

Once you get everything working right though on the computer setup, you may find your CD transport go unused.

 

[MikeW]

Interesting.. i've been having odd ground loop problems in my computer setup every since I grounded it, it never even occured to me that my Grounded Computer (Transport) connecting(Via Coax) to my Ungrounded (by design) dac could be causing my problems. I'll have to experiment with ungrounding my computer.

Also worth mentioning is my Computer is hooked up to a APC Battery Backup with a sqaure sinewave, while my audio equipment is connected to a Monster PC1000 unit, both are connected to the same grounded outlet.

 

[stevesurf]

Quote:

Originally Posted by nspindel But even if I did... If my wireless network was suffering interference from my phone, I wouldn't solve the problem by buying a $5000 cd player, I'd buy a new $50 phone!

There are a number of crystal equipped, (clock) isolated, transports with individual DACs per channel for around half of that $5000 figure, and the prices keep getting more competitive.

Please understand that I am actually a huge proponent of Wireless deployment of various technologies; however, there are many other forms of possible interference that can interrupt your WiFi signal that are beyond your control and thus I would not presently recommend this to my clients.

Quote:

Originally Posted by raylpc I believe Exact Audio Copy (EAC) is able to read the CDs bit-perfect and save to the harddisk without jitters. It's true that the PC CD drives are not as good as those expensive transports. But think about it, somethings are only available to the PC CD drives at ripping but not to the expensive transports at playback - the ability to read the bits for many time and use the error correction codes to ensure the bits are correct. So I believe a properly done EAC rip is jitter-free.

EAC is an interesting and promising method for improving audio extraction accuracy, and if I were interested in getting accurate results in lieu of a high end CDP, I would definitely agree and use this great product, however...it is hardly perfect, and, in some cases, requires much work:

1. EAC can sometimes not automatically detect a CD-ROM drive because of the requirement to use an external ASPI. True, you need to find it and download it to solve the issue, but this is work.

2. Sometimes EAC will incorrectly detect and return silent tracks where there should be audio.

3. EAC cannot, in some cases "hide" large errors that CD Players can, since this type of error correction performed in CDP's is just not available in CD-ROM drives, because they are just that - CD-ROM drives!

4. EAC used fast creates audio artifacts; slow extraction yields far better rips but can take a long time.

5. Having to make decisions on items like speed reduction and glitch removal just make the process that more complex; time that you could be enjoying your music - remember life is too short!

Oh well, this is a very interesting discussion and I must say that the thread contributors are indeed passionate of their approaches.

 

[shplorgh]

Quote:

Originally Posted by stevesurf There are a number of crystal equipped, (clock) isolated, transports with individual DACs per channel for around half of that $5000 figure, and the prices keep getting more competitive. Please understand that I am actually a huge proponent of Wireless deployment of various technologies; however, there are many other forms of possible interference that can interrupt your WiFi signal that are beyond your control and thus I would not presently recommend this to my clients. EAC is an interesting and promising method for improving audio extraction accuracy, and if I were interested in getting accurate results in lieu of a high end CDP, I would definitely agree and use this great product, however...it is hardly perfect, and, in some cases, requires much work: 1. EAC can sometimes not automatically detect a CD-ROM drive because of the requirement to use an external ASPI. True, you need to find it and download it to solve the issue, but this is work. 2. Sometimes EAC will incorrectly detect and return silent tracks where there should be audio. 3. EAC cannot, in some cases "hide" large errors that CD Players can, since this type of error correction performed in CDP's is just not available in CD-ROM drives, because they are just that - CD-ROM drives! 4. EAC used fast creates audio artifacts; slow extraction yields far better rips but can take a long time. 5. Having to make decisions on items like speed reduction and glitch removal just make the process that more complex; time that you could be enjoying your music - remember life is too short! Oh well, this is a very interesting discussion and I must say that the thread contributors are indeed passionate of their approaches.

What I don't understand about this post is that you claim that the slightly larger amount of time it takes to get a perfect copy in EAC makes it inferior to a dedicated CDP. The amount of time saved and convienience of using a Computer is incredibly advantageous over a dedicated CDP.

Plus, this also has nothing to do with the actual sound quality.

EDIT: And as for the actual CD Transport mechanisms being much better in high end CDPs, don't many high-end CD Players use computer DVD drives, such as the Meridian G08?

 

[raylpc]

Quote:

Originally Posted by stevesurf Please understand that I am actually a huge proponent of Wireless deployment of various technologies; however, there are many other forms of possible interference that can interrupt your WiFi signal that are beyond your control and thus I would not presently recommend this to my clients.

Points well taken. It's true that you can't control the interferences from your neighbours or in some other forms. Maybe ethernet connection would be an alternative.

Quote:

Originally Posted by stevesurf EAC is an interesting and promising method for improving audio extraction accuracy, and if I were interested in getting accurate results in lieu of a high end CDP, I would definitely agree and use this great product, however...it is hardly perfect, and, in some cases, requires much work: ... 5. Having to make decisions on items like speed reduction and glitch removal just make the process that more complex; time that you could be enjoying your music - remember life is too short! Oh well, this is a very interesting discussion and I must say that the thread contributors are indeed passionate of their approaches.

Good that you're not argueing on the jitter side anymore. audioengr's link is especially helpful clearing this up. Thanks, audioengr

On the ripping part, you would be glad to know that there's supporting services for this new computer-based audio stuff - a ripping service is readily available for $1.29 a CD: http://www.slimdevices.com/pi_ripping.html

A squeezebox will be my next Chrismas gift. Too bad I already spent too much this Chrismas

 

[stevesurf]

Quote:

Originally Posted by raylpc Points well taken. It's true that you can't control the interferences from your neighbours or in some other forms. Maybe ethernet connection would be an alternative. Good that you're not argueing on the jitter side anymore. audioengr's link is especially helpful clearing this up. Thanks, audioengr

Please forgive the continuation of this, but if you are ripping at speeds greater than the normal read speed of a crystal-equipped CDP, I still believe there is substantial room for error. Until software like EAC gets perfected and CD-ROM drive control is also perfected, I just believe the CD Player method is the best way (low or jitter-free) to go...for now (for the reasons aforementioned).

 

[Tachikoma]

Could one possibly replace a CD-ROM drive with an expensive transport for ripping CDs, for the best of both worlds?

 

[stevesurf]

Quote:

Originally Posted by Tachikoma Could one possibly replace a CD-ROM drive with an expensive transport for ripping CDs, for the best of both worlds?

Nice thought, but It would not be useful, since the CDP is optimized to play at one spead and I doubt it if people would have the patience to rip at the speed the CD is played at! And therein is the whole point...should you use a drive (CDP) that does one thing extremely well, or have to really work at another (CD-ROM) that was designed for mulipurpose use?

Great point, though!

 

[matt8268]

Quote:

Please forgive the continuation of this, but if you are ripping at speeds greater than the normal read speed of a crystal-equipped CDP, I still believe there is substantial room for error. Until software like EAC gets perfected and CD-ROM drive control is also perfected, I just believe the CD Player method is the best way (low or jitter-free) to go...for now (for the reasons aforementioned).

Set in the correct mode (the mode that should be used for critical ripping), EAC makes multiple passes over the CD, comparing results. If the two passes aren't identical, it keeps re-reading it until they are. If the multiple reads never match up, it lets you know there was an error.

It's like counting votes. A CD player is designed to be a really good and consistent vote counter. EAC, by comparison, uses 5 people (each less savvy than Mr. Consistent) to count the votes. If they all get the same total, it assumes the total is correct, otherwise it has everyone recount. Your claim is that if those 5 people are told to count faster than they normally would (a CDROM ripping at greater than 1x speed), their results become unreliable. For any single fast vote counter, this is true. But, the rub is that if their increased speed causes them to make errors, their totals won't all match (it is statistically possible they could arrive at the same mistaken totals, but this possibility is so unlikely it can be ignored). EAC therefore has a way to know when the increased speed has caused errors, or importantly when ANYTHING has caused errors.

I'll take EAC over a CD player any day.

 

[nspindel]

Well said matt8268!

Here is an experiment I'm going to try:

Start with a .wav file, presumably one that I've already ripped from a cd with EAC.

Take that .wav file, burn it to a CD-R, using best-practices for quality audio burns.

Take that burned cd, and rip a new .wav back out using EAC.

Then take the original .wav and the new one, and do a binary comparison. If they are the same, we can retire this thread.....

 

[davvy]

Quote:

Please forgive the continuation of this, but if you are ripping at speeds greater than the normal read speed of a crystal-equipped CDP, I still believe there is substantial room for error. Until software like EAC gets perfected and CD-ROM drive control is also perfected, I just believe the CD Player method is the best way (low or jitter-free) to go...for now (for the reasons aforementioned).

Correct me if I am wrong, but I am pretty sure that with the proper settings, EAC basically IS perfected. I use Accuraterip for all my rips. It compares my rip with a database of other peoples rips. If they are identical (nearly always are) then you can be confident that you have a 100% bit-perfect copy of the data on the CD.

 

[nspindel]

Yep.

By the way, what do the confidence levels in the Accurate Rip report mean? When I get back the report, it looks something along the lines of:

Track Accurately Ripped! Confidence=3 (and then some checksum)

What's the difference between an accurately ripped track with a confidence of 1 vs. an accurately ripped track with a confidence of 10? Does it have to do with the number of people who have posted identical rip checksums to Accurate Rip?

 

[stevesurf]

Quote:

Originally Posted by davvy Correct me if I am wrong, but I am pretty sure that with the proper settings, EAC basically IS perfected.

Check this thread out; no it is not perfected. In the image below, referencing the above link, the last Track's 30 samples are missing!