This may not answer your question directly. It offers some insights to audio quality and appreciation of quality.
Full Quality http://www.audioboxinc.com/quality.htmlSize vs. Quality
The moral of the audio quality story is simple: bigger is better. Compression may be useful for sending tunes over the Internet on a slow connection, but extreme compression has no business being hooked up to a PA system. The solution is to get a bigger hard drive and to carry fewer songs. Luckily, drives are getting bigger and less expensive, and music files are staying the same size.
If you are interested in conducting a less expensive self-test for compression and MPEG sensitivity, you can try these two tests:
Radio signal compression vs. CD
If you have a CD player in your car, tune in a station that is likely to play a song you like from a CD that you own. Listen to the radio, and have your CD loaded and ready. When they play the song you have loaded, listen to the radio for a few seconds, then press play on the CD. The perceived "quality gain" that you should hear represents the difference of quality between CD audio and radio quality. The FM signal quality is significantly lower than the quality allowed by modern computer compression technologies, so the change in quality should be very evident to the human ear.
For this test to be accurate, the volume level of the radio and the CD must be equal. A difference in volume introduces other factors that change the perceived audio quality.
MP3 vs Cassette Quality
If you are tired of hearing how MP3 files are "CD Quality," you can test your ears to see if you can tell that MP3 is LESS THAN TAPE QUALITY. Record a song onto your computer, but don't compress it. Make a cassette recording of this song. Now, compress the song to each available "CD Quality" level your encoder has. Typically, these bitrates would include 128, 112, and 96 kbps.
Record the MP3 files onto another cassette. Now, using a dual-deck system, switch back and forth between playing the recording of the uncompressed music and the MP3 encoded music. Be your own judge, and see if you really can hear the difference.
Now, if you can hear the difference on a cassette tape, shouldn't you ask yourself how close to "CD Quality" the compression format you chose is?