CDs ripped by different drives sound different...nearly fell for it.
Nearly found myself falling for this 'different rippers sound different' thing last night, and coincidentally it's kind of topical, given the recent thread by Staggerlee.
I've ripped knocking-on-the-door-of 450 CDs as Apple Lossless files using a cheap (£15) DVD R/W drive attached to my Mac Mini. Then last night I came across one CD that the drive wouldn't rip properly: Rolling Stones, 40 Licks, 2nd CD, last two tracks. So instead I ripped it with the drive in my iMac.
Then I did the inevitable, which was a bad idea. I listened to the two rips, using 'Sympathy for the Devil'.
I was mortified. While I didn't try AB-X, I was convinced the rip from the iMac sounded fuller and more energetic, with a more rhythmic bass. This was not a Good Thing, after I've ripped nearly 450 CDs with the other drive, plus it went against everything I've preached about and everything I thought I knew about digital audio.
Only one way to sort this. I fired-up Audacity. I loaded-up both rips as separate stereo tracks and aligned them absolutely perfectly with each other. Interestingly, lining them up was harder than I thought it would be because the rip from the external drive was about 100 samples longer at the start for some reason, so I had to zoom right in to sample-level to get them precisely aligned.
Then, I inverted the phase of one file using Effect > Invert, and with more nervousness than an expectant father, I hit play.
Silence. All 6:18 of it, or thereabouts. Audio ripped from CDs is nothing but 16-bit numbers, minus and positive, running past at 44,100 samples per second. Inverting the file makes all the positives negative and vice-versa. The inverted rip was cancelling-out the other file 100% absolutely, because they were perfect mathematical opposites. This in turn means before I inverted the file, they were completely identical (bar the extra samples at the start). No question. No 'might be'/ 'might not be'. No opportunity for subjectivity.
Phew. Sanity restored. The difference was all in my head. No need to re-rip 450 CDs.
Just shows how one can be fooled, eh?
As you were, everyone.
