[3.3.0 Beta Feedback] - Adlib & SB emulation issues

[diegov-au]

Hi @RetroLoom - A big thank you for working on this new beta firmware!

I wanted to report a couple of issues I’ve encountered during testing:

1. YMFM emulation
   There appear to be some minor issues where high frequencies sound slightly off. This is particularly noticeable in Stunts by Distinctive Software, where some higher notes do not sound quite correct and snare hits are occasionally missing. It is also apparent in Street Fighter II, where the intro music includes low-volume snare hits playing on every sixteenth note that are missing entirely. My suspicion is that this may be related to the PicoGUS implementation of YMFM, as the same titles sound correct when using YMFM for FM emulation in 86Box.

2. SB emulation with CT-VOICE
   Sound Blaster emulation seems to be unstable in games that use CT-VOICE (for example Flight Simulator 4, Street Fighter II, and Prehistorik). In these titles, digital sound effects begin to stutter and eventually the game freezes when a sound effect plays.

I’m sharing these findings in case they’re helpful. Thanks again for all the work you’re putting into the PicoGUS firmware - it’s greatly appreciated!

Thanks.

[RetroLoom]

Thank you for the report! I will look in to the high frequency sound issue. This is probably an issue with the aliasing that I was recently made aware of. I will see about getting a fix made for this.

For the CT-VOICE emulation, did this work fine during previous firmware revisions?

[diegov-au]

Hi @RetroLoom - thanks for the reply! The aliasing explanation makes sense. I tested a few other games and noticed that higher-frequency sounds tend to have issues, while lower frequencies sound fine. Look forward to your update!

Regarding CT-VOICE: this didn’t work in the previous firmware either, so nothing has changed with the current release. I just wanted to mention it in case you’re also reviewing the SB code.

Thanks again!

[RetroLoom]

Ok great! That is excellent information. I will find some time to take a look at the CT-VOICE issue as well.