[Coco] [Color Computer] Re: Orchestra 90 - S/S Pak

[James Diffendaffer]

--- In ColorComputer at yahoogroups.com, "tim lindner" <tlindner at ...> 
wrote:
>
> --- In ColorComputer at yahoogroups.com, "James Diffendaffer" 
<jdiffendaffer@> wrote:
> >
> > BTW, does anyone have a dump of the ROM from the S/SP?
> 
> I had a really nice reply to this, but it only made it to the 
maltedmedia coco mailing list.

LOL  That's ok Tim, I read messages on the mailing list but make my 
posts through Yahoo.  
That was exactly what I was looking for BTW.





jdaggett at gate.net wrote:

>Actually what would be better is to replace the OC90 with a full
> function 
>MIDI player. While the OC90 does try and mimic MIDI, it not really a
> MIDI 
>player. The D/A's would definitely have to be expanded to at least
> 16 bits for 
>each channel. The hardest part is generating the sound tables.
> tables for 
>255 instruments at 16 bit is a bit time consuming.
>
>james

The Amiga had 8 bit audio channels and can mimic 16 bit audio by 
changing the volume of two of the channels.  It works but sadly there 
was no volume control on the O-90 to duplicate this trick.

I looked at using the Yamaha OPL chips for a board.  Their sound 
quality is excellent and it wouldn't steal clock cycles from the CPU 
like DMA since the samples aren't in the host's RAM.  They are still 
available but to be honest... without software support it's not much 
good.  

A possible alternative would be to design a S/S Pak & O-90 
replacement that duplicates the functionality of both but adds 
additional features.  Add a control register to enable the additional 
features.  The micro-controller could actually store sound samples in 
an external buffer and play them back through the D/A converters or 
even play midi music with the samples.  As long as the micro-
controller doesn't need to halt the CPU to access the wave samples it 
would be far better than DMA.  Speech functions could even be 
emulated with the micro-controller and samples of the phonemes 
(alaphones... whatever).






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