Originally Posted by bo130
Originally Posted by mcnarus
Also, be sure to tell us:
1. Whether you compared them blind.
2. How you level-matched the outputs, and to what degree of tolerance.
3. Whether you achieved a statistically significant proportion of correct identifications.
There's another BIG flaw here;
How can you make a comparison between an "Apple Mastered For Itunes" download, versus a CD, unless if you've ensured that the same master
is used in both versions.
Two different masters are going to sound different than the other. This is even if they're on the exact
same format. I'd be willing to bet that they'd sound different even with all of the criteria listed above.
All of the above issues are flaws or not flaws, depending on how you compare and what conclusions you wish to support or deny.
The OP for this string of posts appears to be http://www.avsforum.com/t/1494210/poll-is-there-an-audible-difference-between-apple-music-downloads-and-cd#post_23820126
Things are confusing because he raised multiple issues, several of which could easily be audible.
For example, finding an audible difference between a 128 kb download and a 256 kb download is not much of a surprise if the files are MP3s. If they are AAC, then an audible difference is a little more of a surprise, but probably still not much of a surprise. Its well known that 128 kb MP3s often have audible artifacts that are both audible and unpleasant.
If two music files are mastered differently, then again finding an audible difference is not much of a surprise. In fact not hearing an audible difference would be a surprise since the purpose of remastering is to produce an audible difference and the methodology and tools used to remaster files are designed to sound different.
If files are different in terms of both bitrate (when one of the bitrates is low and the other is high like it is here) and
mastering then everybody who is surprised should find a pointed cap and a corner to sit in! ;-)
Anecdote: I was relaxing at a backwoods campsite last week, listening to MP3s I had casually and hastily downloaded to my Sansa Fuze from a collection that I've had for years, but that has a shall we say varied sourcing. ;-)
I was listening to a series of files from one artist (probably sourced together), and I was generally displeased with the sound quality. I went though a menu and looked at the file formats and bitrates. They were all 112 kb MP3s. I later on listened to another series of files from another artist, and they sounded great. I again clicked though the menus and found that they were 256 kb MP3s. I thought "Figures", and then I thought "When will I get my act together and rip those CDs that I have to high bitrate MP3s or even FLAC files?". I'm not going to make any far reaching conclusions about MP3s from this experience, but neither was I surprised and I think that I knew exactly what to do about the bad sounding files!