Reply 40 of 87, by ripa
Thank you very much for those recordings. I thought I there were problems with the emulation, but it's supposed to sound like that.
The silent noise in the menus is caused by the game setting the pc speaker output to a very high frequency (like 500 kHz). That frequency isn't audible directly, but I guess it causes distortion in the speaker which makes it slightly audible. Supaplex also does this between the notes of the music.
Currently, in Dosbox, there is protection against setting such a high frequency, because it wastes a huge amount of CPU time. In my patch the output is set high in such a case. Another solution is setting the frequency to some lower value, which makes the noise slightly audible.
edit: Nope and Atom were trivial to fix. They expect the PIT to have been programmed into some mode - they don't do it themselves. They switch the speaker output between PIT output (expecting it to be high) and forced low. Changing spkr.pit_output_level from 0 to 1 in the constructor fixes the demos.