Re: Au delà de 20kHz, on entend rien

L'article oublie complètement la distorsion des filtres passe-bas.

Tu as lu l'article ?

So the math is ideal, but what of real world complications? The most notorious is the band-limiting requirement. Signals with content over the Nyquist frequency must be lowpassed before sampling to avoid aliasing distortion; this analog lowpass is the infamous antialiasing filter. Antialiasing can't be ideal in practice, but modern techniques bring it very close. ...and with that we come to oversampling.

Et lire la suite (flemme de citer) : Oversampling...

Le 192khz permet d'un filtre simple, avec zéro distorsion à 20khz, ni changement de phase.
Son intermodulation à 33khz, passe à -80dB ! C'est limite audible, de l'ordre de grandeur des erreurs du son 16 bits.

Ben non, le 24bits/192Khz reste inutile pour juste écouter :

That's only half the story. Because digital filters have few of the practical limitations of an analog filter, we can complete the anti-aliasing process with greater efficiency and precision digitally. The very high rate raw digital signal passes through a digital anti-aliasing filter, which has no trouble fitting a transition band into a tight space. After this further digital anti-aliasing, the extra padding samples are simply thrown away. Oversampled playback approximately works in reverse.
This means we can use low rate 44.1kHz or 48kHz audio with all the fidelity benefits of 192kHz or higher sampling (smooth frequency response, low aliasing) and none of the drawbacks (ultrasonics that cause intermodulation distortion, wasted space). Nearly all of today's analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) oversample at very high rates. Few people realize this is happening because it's completely automatic and hidden.
ADCs and DACs didn't always transparently oversample. Thirty years ago, some recording consoles recorded at high sampling rates using only analog filters, and production and mastering simply used that high rate signal. The digital anti-aliasing and decimation steps (resampling to a lower rate for CDs or DAT) happened in the final stages of mastering. This may well be one of the early reasons 96kHz and 192kHz became associated with professional music production

"Quand certains râlent contre systemd, d'autres s'attaquent aux vrais problèmes." (merci Sinma !)