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Re: How is the IIgs beep generated?



Mitchell Spector wrote:
 "Michael J. Mahon" <mjmahon@aol.com> wrote:


Mitchell Spector wrote:

"Michael J. Mahon" <mjmahon@aol.com> wrote:



Michael J. Mahon wrote:


Mitchell Spector wrote:



  Here's a question, one I've been curious about the past twenty years:
Can you reproduce the IIgs "beep" on a stock Apple IIe?


It can be played using DAC522, but with 5-bit rather than 8-bit
precision, so it will be a little "rougher".  Still, it would be
a nice hack.  ;-)

Can someone point me to the "bong" sound in the IIgs ROM?

I'll extract it and try it out on SOUND.EDITOR.


   Not possible. It isn't a digitized waveform (like, say, the "Apple II!
shout in the ROM 3 firmware). In fact it isn't even produced by the Ensoniq chip.

   It's likely just toggling the speaker, very similar to how the Apple
II/+/e/c produce their own "beep" (the IIc+ has a different tone).
The IIgs "bonk" sounds very UN-Apple II-ish or IBM PC speaker-ish
for that matter, especially once you start playing with the pitch.
I wonder how it's produced, is it because of the 2.8 MHz CPU
or some extra sound circurity that is not found in the 8-bit Apple II,
but not part of the Ensoniq either?

   So the question remains: Can you re-produce the IIgs beep
on a stock Apple IIe? (digitizing it doesn't count!) :)

Check out:

http://home.comcast.net/~mjmahon/BONK.SHK

(See my other post in this thread for details.)


Hmm, tried it on my Apple IIGS a moments ago (would have tried it on the Apple IIc I rescued from a recycling center a few
weeks ago, but I just put it into storage with my other Apple II's).

Well, it's quite similar to the IIGS "bonk" yet not at all the same. It still has that very distinctive Apple II speaker sound.
Difficult to describe, but I hear "Bonkzzzzzzt", "Bonkzzzzzt"
rather than a crisp and very defined "Bonk".
    The more I listen to the GS's bell, the more I'm convinced
it's not something that can be reproduced on an Apple IIe.
Example, set the pitch in the Sound Control Panel to the
highest level. Try listening to it over and over, I've never
in all my years of Apple II gaming, programming and tinkering
heard a sound like that from the speaker (excluding, say, digitized audio, though even then it wouldn't be as clear).

I don't know what parameters you were using, but...

I just happened to get access to a IIgs this weekend.

The correct parameters for the default IIgs "bonk" are:

POKE 6,83
POKE 7,2
CALL 768

That reproduces it quite well.  The volume is about 2/3 the max
volume of a raw beep, but the ear doesn't really care.  ;-)

-michael

NadaNet and AppleCrate II: parallel computing for Apple II computers!
Home page: http://home.comcast.net/~mjmahon

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