Originally Posted by Earwax
It's interesting that higher flac bitrates didn't predict which pieces you'd have trouble ABXing. That's not at all what I would have guessed.
I am curious about a couple of things. Can you describe the type of difference you heard between the Shostakovitch tracks? How long did it take you to do all those trials? Was this all done in one day or spread out over time?
The differences that I heard were mostly in depth of sound and, I guess, realism. On the less "active" sections of the piece it was impossible to differentiate them. On the complex sections, I found it much easier. I believe I was 14/14 on that test before testing the slower sections of the piece.
Violins were the most helpful to me in determining which one sounded more real, but I really had to listen for the very end or very beginning of each note: that was where the differences were located.
The trials took me quite a while, maybe about 3 hours or so. It couldn't be more; it might actually be a little less, but that time includes all the breaks I took, some of which were rather long. The test was done in one day. I did discover some important things about audio testing in general.
The more times you hear the same track, the more easily fatigued you become. Listen to the two versions too many times, and they begin to sound exactly the same, despite a minor difference you may have noticed during the first five replicates. Because of this, I had to constantly test different sections.
Originally Posted by progo
Actually, while the flac bitrates don't mean anything, they might correlate to loudness. In general, hot CDs I've ripped are usually over 1000 kbps but the classical and jazz can be 400-700 kbps. But the numbers don't mean anything in the end. Just the saved amount of disk space.
I'd definitely agree with that. The newer the CD is, the higher bit rate I get off of it in FLAC. The only reasonable conclusion is that the higher the bit rate, the hotter the CD is. All of my good CD's: the first pressings, classical music, recordings mastered by the artist, etc. - All of them have relatively low bit rates.
Originally Posted by Headdie
1. When you heard a difference between MP3 and FLAC, was it a continuous difference (meaning that you could hear it all time), or was it a ponctual difference (meaning that you could hear it at some places/passages only) ?
2. I understand that MP3-320 is a very good format, but the encoder could be the weak link. It would means that encoding with WMP or LAME would not yield to bit identical MP3 files. Is that tested and confirmed ?
1. I could hear the difference during some small intervals only. Usually less than a second or so in length.
2. The encoder and program definitely make a difference. At first, I tried some 320 kbps AAC files I had on iTunes. A long time ago, I had burned some CD's using iTunes into that format.
Since I still have the same CD's in lossless form, I compared the two. The ABX test was not required. The difference I heard was substantial enough that it was highly unlikely it was all in my head, unless I'm just crazy.