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  3. 1230454626

Considerable Improvement with EAC Rips

associated equipment:
-Squeezebox III w/ Transparent Reference Digital Link .wav or .aiff
-dCS Delius
-dCS Purcell Upsampler 1394 (DSD)
-Levison 336
-B&W N802
-Transparent Reference Cabling and Power Conditioning
-ASC Tower Traps

I will be short and to the point. I think error correction, or "secure ripping" is absolutely crucial to hard drive based music server performance and I think the free program EAC probably performs this task better than iTunes. The difference is audible.

On disc after disc, EAC ripped tracks had a more refined, pleasant presentation, greater resolution, improved dynamics, with better imaging and instrument separation than iTunes tracks. In addition, electric and acoustic bass was tighter with more articulation and string attack. The imaging of loud swells in the music that on the iTunes tracks would sound "congested" held together more on the EAC tracks. Vocals were not as boomy or forward sounding. It goes on and on.

I tested with a fellow audiophile and we both heard and were able to describe to each other the same type of improvement on each track in most cases. In every case we heard a material difference in the tracks and on the majority of the discs we could successfully identify and distinguish EAC tracks from iTunes tracks in a blind test.

In some cases, tracks that iTunes ripped rather quickly took over an hour to rip as EAC read and reread bad sectors on the disc. Average rip speed was around 4-6x normal playing speed and on some discs dropped as low as .1x normal playing speed. We used iTunesEncode to allow EAC to automatically use iTunes' encoders to convert the raw EAC wav into .aiff and add it to the iTunes library with the proper metadeta. The entire process of EAC ripping and adding to iTunes is one click, once setup properly.

EAC indicated it was performing error correction on several discs that were thought to be in good enough condition for real time playback on a CD transport.

As a side note, the CD drive we have used has, what based on my research (also known as googling), is the best combination of features for a CD-ROM ripper: 1. it does NOT cache audio when ripping 2. it uses c2 error correction and 3. it utilizes "accurate stream".

I believe the final result with EAC is as good, if not better than the Goldmund Mim36 transport the Squeezebox replaced. On almost every disc I found myself saying "it sounds like the old transport!"

The bottom line is that if you are seriously building an archive on PC you should probably at least test this program. If you can't bring yourself to use EAC, at a minimum, iTunes error correction should be engaged.

This is a tweak for serious listening and like a lot of audiophile upgrades the differences are subtle, but important. I could not identify a difference on my Pro-Ject Headbox SEII, Sennheiser HD600 headphones and PC soundcard, but out of my main system it was obvious to me.

In conclusion, the right drive and EAC has made the system sound better than ever, without a doubt. There may be other software that rips as well or better but I am not aware of it. It also suggests computer software may play an important role in the future of the hobby, especially with USB DACS on the rise.

At the very least, the meticulous manner in which EAC reads and rereads suspicious sections of a disc, the ability to detect and compensate for unwanted drive behavior like caching, the reduced speed at which it rips, the accuracy reports it gives, and the program's reputation give me piece of mind that my files are about as good as they could be.

It is either my imagination or the best free tweak I have found to date.
blackstonejd
blackstonejd OP
152 posts
 
Here is the thing. When I rip the same track twice using iTunes w/ error correction and then use Foobar to compare the two .wavs, it typically finds NO differences. In one case it found a difference of 24 samples which obviously is negligable. The same is true with two consecutive rips using EAC. So it is not as if iTunes is not capable of producing consistent results. It just produces results consistently different from EAC--if Foobar is to be believed.

Whether those difference are material to sound quality I don't know--but Foobar at least gives some support to the idea that the files are different IN SOME WAY.
blackstonejd OP
152 posts
 
Dtc, I think your hunch about the EAC's offset correction (in my case it was set to +6) throwing Foobar off was correct. If you go into the EAC folder and temporarily disable the Accurate Rip function by changing the filename of acurraterip.dll to acurraterip.dll.whatever, you will find when you fire up EAC that you can now adjust your read offset and that it is set to +0 by default.

When I used Foobar to compare an EAC rip with +0 offset to one with +6 I found that it reports the millions of samples that we have been encountering. Further when I Foobar compare the +0 offset EAC .wav to an iTunes .wav, Foobar reports NO DIFFERENCES!

So I think at this point both EAC and Foobar are telling us that there is no difference between the EAC rips and the iTunes rips--at least on the track I tested.

At this point I have to acknowledge that there may be have been a powerful placebo effect at work in my listening tests. I can't say I believe any longer that EAC is better under all circumstances. On the disc I tested today I could not detect any difference in sound quality between the two. I was able to play it a bit louder today because I had the house to myself. That disc was in pretty good condition.

I will continue to use EAC because I like the way it behaves and the feedback it provides, but I am not sure what if any value it adds with respect to sound quality.
dtc's avatar
dtc
1,024 posts
 
Very interesting. I will play with the offset when I get a chance. But it sounds like you figured it out. Great work. Now we can compare real differences, rather than these offset issues. I do think EAC may handle damaged disks better than iTunes. I have a couple of tracks that iTunes will not read. If I can remember which ones they were I will see how EAC does it, although they were not on CDs I listen to very often. I have read reports of people finding differences between EAC and iTunes until they cleaned the disk. EAC read the dirty disk correctly but iTunes did not. I did spend some time with the ABX capability of foobar today trying to hear differences - it plays 2 different files randomly and lets you pick which one it is playing and records your results. You can set the start and stop times, so you can zero in on particular parts of a track very easily. Makes blind testing very easy. It was hard for me to do better than 50/50 when comparing the iTunes and EAC rips. If you have not used it you might give it a try. Just need a PC with an optical out or a usb to optical/coax converter. It is a function I have wanted for a while, so was glad to find it, even though I do not plan to use foobar on a regular basis. I may use EAC in the future - but since I recently ripped everything with iTunes I will probably just stay with that. I am really amazed at the sound quality you can get these days with free software and a little hardware. The old European school of thought that the source is the critical part of the chain is still valid - but it is no longer as expensive, although the dac is still critical to the sound quality - and for many it is the weak link. Of course for you it is a strength of your system. For me having easy access to all my CDs is the great pleasure of these systems. Using the visual interface of iTunes is much easier than trying to remember what I have on the shelves. Great discussion and glad that we got to the bottom of at least some of this. But I still will not give up my vinyl. Enjoy the music.
dtc's avatar
dtc
1,024 posts
 
I was able to get foobar to do the correct bit compare, but I think with slightly different settings than you used. When I set read offset to 0 I got compare results that the files were of different size. So I changed combined read/write compare offset to 0 and then the compares worked. I am not sure exactly what these offsets do to the actual file, but my impression is that they do not change the actual bits of the music, but rather adjust spacing of the tracks. I guess for making exact copies the offsets are important, but for playing the music it should not make a difference. Is that your understanding?
blackstonejd OP
152 posts
 
Yes, exactly. It has to do with alignment of the drive head. There is absolutely nothing I have found that suggests this has anything to do with sound quality. The "correct" value for offset depends on your drive.

I'm not really sure what it does or what value it adds but it does not change the bits of the music. It just moves them enough that Foobar can't match them anymore.
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