Re: Ultima 3 "Mockingboard" version.

[Rubywand <rubywand@swbell.net>]

"Michael J. Mahon" writes ...
 ....

> Ah, but the SID had a capability that the GI PSG's never did: full ADSR
> programmability.  The Attack rate, Decay rate, Sustain level, and Release
> rate were separately programmable, giving the SID the ability
> to sound much more "musical" than the PSG, which, as its name suggests,
> is better suited to sound effects, particularly cyclical sound effects.
> 
 ....

     Pretty much agree.

     There are many similarities (3 Voices, 16-bit frequency resolution,
option for Envelope control for each voice, 4-bit level control per Voice,
and one output via a common Volume control). On the other hand, PSG has one
Envelope generator, while SID has a separate Envelope generator for each
voice. And, as you mention, the SID gives you much better control of envelope
components. It also has switchable filtering of Voice outputs and a way to
supply feedback to the system CPU.

     The PSG has a separate Noise generator which the SID lacks. The NG
frequency can be varied and its output can be mixed with any, none, or all of
the Voices. On the SID, any Voice can output a Noise waveform instead of a
normal tone. And, there are a few other differences-- e.g. the SID supplies
analog joystick inputs.

     In general, the SID has more built-in sound making capabilities than the
PSG. Of course, a PSG Voice's envelope could be controlled via software; so,
Mockingboard users are not excluded from improving accuracy of instrument
sounds.



Rubywand