@AdamCatalyst
Here is the earliest RA picodrive core that Tetsuo included in the WFL plugins pack V6. It is 1.9.0 and probably will not solve the issue but worth a try if you have not already tested.
I do have a WiiU set up in the front room but have not got around to testing yet. I will tonight or tomorrow and give you feedback if the WiiU is indeed causing the audio issue.
If you have not played the Virtua Racing Mirror hack for 32x, highly recommended. I own the Genesis VR and played countless days back in 94-96. PGA Tour Golf II, NBA Live 95, NHL 95 and Road Rash II, Virtua Racing were the games we all got together to play. Such great memories!
Speaking of Genesis NHL, i see you released '23. I have played a few games recently, great work again my friend.
Short story about the NHL series. One of my college friends had NHL Hockey (92) back then but he lived off campus. So i got to play a little here and there when he had weekend parties but i was hooked and saved my money to purchase 93. All i had at the dorm at the time was PGA Tour Golf I and Side Pocket and Sonic. The days & battles me and my friends spent on NHL 93 was crazy. Needless to say we all became ringers, putting up 25-30 goals in 5 min periods against the computer was common. After graduating from JuCo and coming home, my best friend who just got out of the Army bought 94 for the Sega CD and it blew our minds with the one-timer, what a revelation to the series. I ended up buying 95 and i believe i have sunk more time into that sports game than any other (EVER), Ken Griffey MLB SNES would be a close second. I did get NHL 96 from a local pawn shop back then but it could never hold up to 95 in my opinion. In conclusion, i don't believe i have ever played 94 on the actual Genesis hardware, only Sega CD or through emulation. I know 94 is considered the very best, but for me, 95 will always hold that status. NHL 2004 on GameCube was excellent as well.
Thanks for listening/reading my "Short" story.