As mentioned in the 1st post, I'm waiting for the results of my blind MP3 test...
In the interim, I wondered if my measurement setup can be fooled by MP3. So, with the AUNE X1 still connected, lets run the test signal lossless vs. MP3 through and see! Summary results: 14345 Not bad! When condensed into a single number, the different MP3 bitrates look fine! However, here's an example where single digit measurements can be very deceiving. Frequency response: 14346 Again, MP3 looks pretty decent. However, you can start seeing the lower bitrates drop off in the high frequency prematurely beginning with 128 kbps (green) in sequence. Noticeable effect with lossless compression but not bad... Noise: 14347 Once again, not bad... What can I say, silence doesn't need many bits to encode :-) THD: 14348 The "money shot" right there! It's obvious we can now differentiate the lossless (white) from the lossy compressed. There appears to be a large gap between the distortion from 128 to the rest. 192, 256, and 320 kbps all congregate together pretty close and I suspect for many of us, this correlates to 192 kbps+ being quite transparent. This is why MP3 compression effect is probably quite close to VERY SEVERE jitter distortion (? at least tens of nanoseconds) in that it's correlated to the signal itself beyond simply single sidebands. Conclusion: You cannot fool machines with psychoacoustics!!! +-------------------------------------------------------------------+ |Filename: MP3_THD.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=14348| +-------------------------------------------------------------------+ ------------------------------------------------------------------------ Archimago's Profile: http://forums.slimdevices.com/member.php?userid=2207 View this thread: http://forums.slimdevices.com/showthread.php?t=97950 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
