cuddihyd@cshl.org (David Cuddihy) (06/29/91)
If I wanted to have a program that was to play samples as controlled by say a MIDI device or something like that, the point being I want a real time response how would I go about multiplexing in order to get say 8 voices? In theory it seems very straight forward: You take the two samples in question, take the one to be played back at the higher frequency and use that as the AUDxPER, copy that into a piece of memory pointed to by AUDxPOS(??) of a length AUDxLEN and then copy the slower frequency sample into that memory area every Fz2/Fz1 word (Not actually copy but 'multiplex' or do some sort of an averaging routine... Infact you can get fancy and plot slopes or Simpson curves or god knows what across the gaps between sample two's active words to 'fill in the gaps' but thats not really the point) The trick here is to get an AUDxLEN long enough as to let Paula give enough time to the processor to let it run this little multiplexing routine. Fine and dandy, except at 7.1Mhz(or whatever) this will NEVER HAPPEN!(Or am I wrong) Can someone suggest an alternative method to this multiplexing porblem? Much appreciated, -Dave
crain@cpsin3.uucp (Steven Crain) (06/30/91)
> [paraphrase] can someone suggest an alternative means of multiplexing?
You can feed data directly to the D/A converters (Paula) via on of those
memory mapped ports, if you set the correct mode (via another of those
ports), which is the way it is done with those 8-track
Noise/Soundtracker-style players (Startrekker and oktalyser I believe).
Steve
crain@egr.msu.edu