Re: Question for Audio Animator owners...

[Mitchell Spector <mitch2gs@hotmail.com>]

Drew <goggledrew@gmail.com> wrote:

>Did some tests and indeed the sound is nothing to do with the AA
>(sound still lingered using onboard jack and removing the AA card). It

    Ah, I thought that would be the case. A long time misconception
is that a stereo card is a "sound card", in the same sense as on the
PC. It is NOT. All the sound generator circuity is on the motherboard.
Why Apple choose to tie all 8 stereo channels into 1 monaural (that's 
then mirrored to the left and right channel) requiring the need for a 
third party stereo card, is really bizarre.

    IIgs stereo cards are such a simple bit of circuity they don't even 
need a physical slot, they just use it for power. The Audio Animator
was a bit unique though, it bypassed the Ensoniq's ADC (used for 
recording audio samples) and contained its own that was inside the 
shielding external mixer box. Not to mention MIDI I/O capability, so 
the slot was used for more.

>seems my ROM03 machine must have an issue with its sound circuit. I
>realize now that i must have changed my main GS mobo at the same time
>as installing the AA, hence i was certain it was something to do with
>the AA :).
>
>I will have to take the mobo out and have a look and see if i can see
>anything obvious....maybe its time to hunt down another ROM03 board :)

    I have noticed one strange glitch on some ROM 01 and ROM 3 
motherboards (including the replacement ROM 3 board I installed about 
a year ago). Run Music Construction Set, open the song "Leroy". The
first two chords of the 'Synth' instrument on the lower bass section make
this distorted scratchy/static sound after the note has played. It's like
it doesn't cut off. On good motherboards there is silence after the 
chords, no static. I wonder if other programs aren't affected....

    My theory is either it's different types of DRAM chips used for
the 64K of DOC-RAM, or some differences in the support circuity
used around the Ensoniq (maybe even certain revision of the 
Ensoniq 5503 chip itself?). 

Mitchell Spector