Add volume control to the sim sounds

[DianaTavares]

I had an interview with the KL simulation that already has some sounds. The student that I was interviewing wanted to decrease the volume of the simulation, but not the sound of the computer because she want to continue hearing me well. We realize that not was not possible.
I find very useful a control that can control the volume of the sounds in the simulation for class in person and online set-ups.

[emily-phet]

@jbphet I think we'll see more requests for this kind of feature. It came up long ago, but we didn't tackle it at the time because of too many challenges to tackle at once.
I'm not sure where this sort of issue should go. It's just something I think folks will want, no idea how/when to prioritize it. Maybe you have an idea? It's sound centric but would involve changing the nav bar of the sim so I asked Diana to put this issue in Joist.

[jbphet]

In terms of the sound library, it would be fairly straightforward to support this. There is a "master gain node" at the end of the signal chain that is currently used to mute the signal, and we could add capabilities to make it have a volume value as well. Either that or just add another gain stage in the signal chain to control this (I think they are relatively cheap in terms of memory and computational power).

I therefore think this is probably more of a design question. We could have a volume control in the "Preferences" dialog, but that wouldn't handle every case, since not all sims have this dialog. Perhaps we'd to that volume control, and then could have some sort of a popup with a volume setting associated with the (non-preferences dialog) sound button instead of the current toggle behavior, perhaps something that looks rougly like this:

We would also need to decide if this control would affect only the sounds produced by tambo or also those from voicing. Including voicing would make more sense to me, but would likely be a bit more complex.

I'm happy to work on the design and/or implementation of this, but my time is already spoken for in this iteration. Assigning back to @emily-phet to decide on who should work on this, the priority, and whether to make it an item for an upcoming iteration.

[emily-phet]

I'm unassigning myself, and letting this issue be orphaned. I think this topic will come up again in the future, and if someone searches they can see that others ran into this need as well.
I don't have funds for making this change, that will be a decision for Kathy and others in the future.