by ff123
Can you hear harmonics in acoustic music above 14kHz or so? Find out for yourself. I ripped about 8 seconds of music from the first track ("Limehouse Blues") of the Propius CD Jazz at the Pawnshop, (PRCD 7778). As you can see from the first spectral plot below, there is significant energy all the way out to 20kHz.
Next, I encoded to mp3 using mp3enc 3.1, qual 9, at a bitrate of 128kbs. The spectrum of the encoded file is truncated at about 14kHz.
I tested my own hearing (subject to the limitations of my audio equipment) by doing an ABX comparison of the two files using the PCABX program to effectively make it a double-blind listening test (see Arny Krueger's website to download his program). I scored 11 out of 16 trials, which means that I was guessing about which file was which. I listened at a relatively loud level, with headphones, at night (when my household is quiet). I could detect no artifacting, nor any "muffling" of the sound by mp3enc.
I've made the two files publicly available for you: lime86.pac and lime99.pac stored on my Audio Samples Page. They have been compressed using the lossless compressor, FLAC. One of these is the original, the other is encoded. Which one is which?
To see what others said, look here. But first listen for yourself!
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