Hi Arno, I couldn't agree with almost any of your statements. ad1. "Initial quality" means quality of location sound recordings, after first A/D conversion on your audio recorder. It could be 44.1kHz, 48kHz, 96kHz or any sane of even insane Sampling Frequency, 16 or 24 bit word lenght. [As we know according or thanks to Nyquist law we can percieve only half frequency range of the sampling rate (e.g. 32kHz sampling rate <= 15kHz freq range etc)]. You can't have high initial sound quality with low sampling frequency. It's just not possible. No, upsampling, playing low sampling frequency (e.g. Fs=11kHz) poor cracking sound at 88kHz will give you the same weird cracking sound quality. it's simply misundestanding. You simply can't hear the difference after upsampling process. BTW Carenado have those 44.1kHz sampling rate sounds and is doing the sampling rate down conversion without the reason, as if out of spite. ad2. I don't have a clue what do you mean by therm "restitute". If you're saying people don't have speakers with tweeters I wouln't agree. High frequencies are much easier to emit than low frequencies. Also every healthy person (except really old man) can hear approx. 15-16kHz frequency range without the problem = they actually hear the difference between Fs=32000Hz and Fs=44100Hz I don't even bother poor tiny laptop speakers (which high frequency range is quite good!), or pilots headsets used for full frequency range playback (which is funny but non realistic assumption). ad3. Of course simmers sensitivity to sound quality may vary. Not everyone has trained ears, on the other side some well known flight simulator developers are quite deaf. But my goal is to have a good sounding airplane to very closely emulate the sounds from my real life flying, not a buzzy toy (just look for every embarrassing default sound and X-Plane sound architecture). X-Plane is intended for sound processing. Believe me the old days ('80) of digital audio infancy are gone... The CPU sound load is so minimal even using (not perfect) but high quality DreamEngine plugin or similar. BTW I appreciate your sound invention and ideas in T28.