[comp.sys.mac.misc] Sound incompatibilities with accelerated SE

lau@aero.org (David D. Lau) (05/08/91)

I just bought a Mobius 030 accelerator / Full Page display.  It works
great but the sounds from the Mac sound scratchy when the accelerator
is enabled.  I was informed by Mobius that some sound drivers are not
compatible with many accelerator boards for the SE.  I was wondering
if anyone knew of a fix or solution to this incompatability.  I read
in MacUser somewhere that this was a problem in alot of accelerators.
Thanks

David Lau
reply to : lau@aerospace.aero.org

REEKES@applelink.apple.com (Jim Reekes) (05/09/91)

In article <1991May7.230349.13004@aero.org>, lau@aero.org (David D. Lau) writes:
> 
> I just bought a Mobius 030 accelerator / Full Page display.  It works
> great but the sounds from the Mac sound scratchy when the accelerator
> is enabled.  I was informed by Mobius that some sound drivers are not
> compatible with many accelerator boards for the SE.  I was wondering
> if anyone knew of a fix or solution to this incompatability.  I read
> in MacUser somewhere that this was a problem in alot of accelerators.
> Thanks
> 
> David Lau
> reply to : lau@aerospace.aero.org

The Sound Manager and the older Sound Driver are very timing dependent.  By
changing the timing when you added the accelerator, you've caused all of this
code to "go too fast".  I've heard that some accelerator people have written
patches for the driver, but I don't know of any solution for the Sound Manager.
I don't have an accelerator, so I don't know exactly why or how it fails.
This problem exists, and it's in System 7 too.

Jim Reekes E.O., Macintosh Toolbox Engineering (working on the Sound Manager)

hunter@oakhill.sps.mot.com (Hunter Scales) (05/11/91)

REEKES@applelink.apple.com (Jim Reekes) writes:

>In article <1991May7.230349.13004@aero.org>, lau@aero.org (David D. Lau) writes:
>> 
>> I just bought a Mobius 030 accelerator / Full Page display.  It works
>> great but the sounds from the Mac sound scratchy when the accelerator
>> is enabled.  I was informed by Mobius that some sound drivers are not
>> compatible with many accelerator boards for the SE.  I was wondering

	That's interesting, they told me that it was a Sound Manager
	problem but that all of their SE's didnt have the problem!
	I specifically asked it all had it and he said "we have some that
	do and some that dont"

>> if anyone knew of a fix or solution to this incompatability.  I read
>> in MacUser somewhere that this was a problem in alot of accelerators.
>> Thanks
>> 
>> David Lau
>> reply to : lau@aerospace.aero.org

>The Sound Manager and the older Sound Driver are very timing dependent.  By
>changing the timing when you added the accelerator, you've caused all of this
>code to "go too fast".  

	I dont understand, is the sound software timed? 
	If so, why doesnt the sound appear to be shifted in frequency?

>I've heard that some accelerator people have written

>patches for the driver, but I don't know of any solution for the Sound Manager.
	How does it work for different speeds of processors in the SE
	and the IIci, for instance.  Seems like the same solution would
	work for accelerators?

>I don't have an accelerator, so I don't know exactly why or how it fails.
>This problem exists, and it's in System 7 too.

	I was also told by Mobius that system 7 fixed the problem.
	Sounds like they tell you any lie you want to hear.

>Jim Reekes E.O., Macintosh Toolbox Engineering (working on the Sound Manager)

-- 
Motorola Semiconductor Inc.             Hunter Scales
Austin, Texas                           hunter@prometheus.sps.mot.com
#include <disclaimer.h>