[squeak-dev] Adjusting the volume of a sound as it's playing

Jim Rosenberg jr at amanue.com
Sun Aug 18 06:37:21 UTC 2019

Apologies in advance if this has been fixed in more recent versions of 
Squeak; I'm developing at the moment under Squeak 4.3.

I have a project in which I'm adding sound to a longstanding body of 
artistic work implemented in Squeak. I'm going to need several sounds 
playing at once; typically there will be one or more instances of 
RepeatingSound and probably just one (or zero) MixedSound. When the 
MixedSound comes on I want to turn down the volume on the other sounds. How 
to do this. It has been driving me crazy. I was getting absolutely nothing 
to work to actually change the volume.

There seems to be the right method in AbstractSound -- 
adjustVolumeTo:overMSecs: -- but in Squeak 4.3 this seems to not be 
properly overridden in MixedSound or RepeatingSound. I was getting 
absolutely nothing to work until I stumbled onto changing leftVols and 
rightVols by brute force at an explorer. This DOES WORK.

leftVols and rightVols are instance variables in MixedSound, so it seems to 
me they should be changed by MixedSound's own implementation of 
adjustVolumeTo:overMSecs:. RepeatingSound should have its own 
implementation which just passes on to its sound.

Maybe there's a better way to do this, but given that AbstractSound does 
have the right method, it seems like overriding here is the right thing to 


-Thanks, Jim

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