Re: Ultima 3 "Mockingboard" version.

[mjmahon@aol.com (Michael J. Mahon)]

Rubywand wrote:

>Linards Ticmanis writes ...
>> 
>> Rubywand wrote:
>> > The C-64 definitely has better built-in sound than the 8-bit Apple II's.
>> > You especially notice the difference in stuff like the opening song for
>> > Alternate Reality. The Mockingboard's Programmable Sound Generator chip
>> > gives an Apple II the same capabilities.
>> 
>> Does the Mockinboard contain any custom chips? Or is it something that
>> could be cloned with a bit of dedication?
>> 
> ....
>
>     Mockingboard uses off-the-shelf chips. Music and sound effects are
>produced using the General Instruments AY-3-8910 Programmable Sound Generator
>(PSG). (Some Mockingboard models include a chip to produce speech. Pretty
>sure these were also off-the-shelf items.)
>
>     The 6581 Sound Interface Device (SID) chip used in the C-64 seems to
>work almost exactly the same as the General Instruments PSG. I'm pretty sure
>the 6581 is a proprietary chip.
>
>     The PSG and SID can deliver three musical 'voices'. Mockingboard "Sound
>II" (and some other models) have two PSG chips. This gives the Apple II user
>two-channel sound and twice as many musical 'voices' as C-64 can produce.
>
>     Besides the PSG, Mockingboard's use the 6522 for interfacing. A small
>audio amp chip (think it's the LM380) is included to allow directly driving
>speakers. (If you connect to an external amp, you can omit the LM380's.)
>
>     So, yes; a Mockingboard for playing music and handling sound effects in
>games like Ultima III would be fairly easy to build.

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.

-michael

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