stridey said:
I agree that AAC is inherently lossy. My argument is that you can't actually hear the difference. I'm interested in knowing; if you consider yourself to be a professional in audio (I don't know), can you hear the difference in my sample snippets?
I've had a lot of people claim to hear the difference, but nobody yet has even been able to identify with accuracy which pieces begin lossy and end uncompressed, and which do the reverse.
Can you tell me how you made the files please, and what format you are streaming them in, what application did you use that can play back 2 different audio codecs and crossfade between them, not even ProTools will do that, all the Pro audio systems will convert the incoming audio to a set file-type.
I'll need to know the file creator and codec settings for each version and the final encoder that created the files you are using, and I'll need to be able to download them into a system I can play them accurately from, as the speakers on my PowerBook are genuinely useless for audio comparisons.
A better test is to play 2 separate versions of the audio from 2 files through the same delivery system, you can still run blind test (we do it all the time in the Uni and in the MPG, and the AES does "golden ear" listening tests on a lot of new systems regularly).
This gives the audience a much better chance of hearing the differences, which are night and day in AAC/aiff terms.
There are too many unknown variables in your tests, I have no idea what I'm hearing, or even if the effect you describe has survived the transcoding process. The other issue is that the audio clips are far too short and the source files on three of the clips show significant distortion in the original audio recording process, classical music is thought by some to represent a much greater challenge than contemporary music, but you need a couple of minutes of each type to be able to appraise the tonal qualities accurately.
For the record, I'm a 20 year commercial recording engineer and I lecture in audio technology at a London University, I'm also a musician.