First post, by thecoreyburton
I've noticed both in DOSBox and when using WoodyOPL in adplug, there are audible clicks at the start of certain notes. Originally, I posted this as an adplug issue, because I wasn't sure where the problem was or what the best way to fix it was. Malvineous provided some good insight and directed me here, to see if it could be tackled on the OPL emulation level.
Here is an example file, demonstrating the issue (it's the menu song from Wolfenstein 3D, played back using WoodyOPL at 49716hz using adplug).
If you playback the clip, at roughly 2.85 seconds there are three bass notes (before the melody repeats). On the first of these bass notes, right at the start, one such "click" is present. If you amplify the clip, the problem becomes visually apparent, with a large jump being present when the clip starts to play the next note. There are several instances of the "clicks" throughout the clip and they all exhibit the same behavior.
I'm not sure the best way to tackle this and as far as I can tell, this isn't something that was present on the hardware itself.