Actually it seems like it just doesn't make any sounds. Or if it does it tries to make sound with a tone instead of noise.
It is definitely making a noise sound for me, quite distinct from the tone, but it probably isn't right yet. What does the rushing water sound like for you in Black Cauldron when you're in the scenes with the stream?
For King's Quest 2, the waves breaking are meant to make a noise sound, which I've seen on Youtube videos for the PC JR version. I know that AGILE doesn't sound right for that one either. It sounds a lot more like crashing rather than a wave breaking.
I can't find any authentic IBM PCjr footage except for this video
The only noise that sounds however is when the hovercraft is moving at 1:18.
Thanks. I'll take a look at that one later today.
The only other thing I notice is that unlike the above footage, the tones don't have a volume envelope. The volume falls off at a certain rate on every tone on the PC jr and Tandy 1000. ScummVM's PC jr emulation is the most perfect I've heard both with noise channel and tone volume envelopes. Even better than DOSBox's.
I have seen in the comments that DOSBox uses the MAME source code for this emulation. Haven't checked to see if they're currently in sync, but a comment in the code implies that it was at some point.
I think I see what bit in the scummvm code is handling this volume envelope. There is some "dissolve" data defined, which is set differently for different AGI versions. Hmmm, not sure how that could be the case though, as what you are describing sounds more like a feature of the hardware rather than AGI versions. But "dissolve" does sound like it might be related to what you describe. I noticed that NAGI also has that dissolve data defined (a comment in there also calls it "fade out"):
https://github.com/sonneveld/nagi/blob/master/src/sound/sound_gen.c#L46From what you can hear, do you think that this "fade out" happens from the point that the tone ends, i.e. at the point that its duration count has ended? Or do you think it fades out leading up to the point where the duration count ends? - This distinction will determine whether each channel needs to generate/mix both its current tone and also the fade out of the previously tone simultaneously.
Incidentally, I just tried running the AGI Demo 2 game (which has the SQ2 demo in it) and it doesn't seem to like it. Navigating to each page of demos with F9 and F10 works once in a while, but I can't hit a number to select a demo to run. It just doesn't respond.
That sounds like something I can hopefully fix more quickly than how the sound sounds. I'll take a look later on.
Keep feeding through any issues you find. I think I'll start adding them as github Issues so that I can track what I've looked at and fixed.