23kHz? Bezne zvukovky su 48kHz, takze 24kHz je teoreticky limit, prakticky este mensi. Odkial 23kHz zoberies? Z AudioCD asi nie, jedine tak z DVD alebo SACD. 23kHz v MP3? Asi nie:
Kód:
rainbow@pentium:~$ file /usr/share/sounds/alsa/Side_Left.wav 
/usr/share/sounds/alsa/Side_Left.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 48000 Hz
rainbow@pentium:~$ lame -b 320 /usr/share/sounds/alsa/Side_Left.wav 1.mp3
LAME 3.97 (beta 2, Jan  6 2006) 32bits (http://www.mp3dev.org/)
Using polyphase lowpass filter, transition band: 20323 Hz - 20903 Hz
Takze repraky na 23kHz kludne, len tych zdrojov takeho zvuku je trosku malo.

BTW. Kolko ludi nepocuje ani piskanie TV? Dost. A to je len 15,625 kHz.