SGB: Keitai Denjuu Telefang - Sound issues on title screen

[Blaziken257]

Summary

When playing Keitai Denjuu Telefang (a dual GB/GBC game) on SGB on an FXPAK Pro cart, the title screen has issues with the voice sample; there is a buzzing sound that drowns out the sample. This issue is not present on any stock Nintendo hardware.

Hardware/Firmware/Software versions used

• Super NT on stock firmware 5.3 and JB 7.2 (possibly earlier firmwares as well, but untested)
• FXPAK Pro firmware 1.11.0
• Retail Japanese versions of Keitai Denjuu Telefang - Power/Speed Versions
• English fan translation patches of Keitai Denjuu Telefang (most recent patches can be found here; they contain a custom voice sample, but the issue is the exact same nevertheless)
• Occurs in both SGB1 and SGB2 BIOSes

Was not able to test on a stock SNES, since my SNES doesn't seem to want to boot my FXPAK Pro cart (even though it boots licensed carts just fine).

Details

Telefang has a voice sample shouting the game's name on the title screen (the English patch replaces this with "Let's Telefang" instead). This works fine on real hardware (including DMG, SGB, SGB2, GBC, and all GBA variants), but when running this on an FXPAK Pro, there is a loud buzzing noise, and the actual voice sample is largely drowned out and difficult to hear.

The English patch also contains SGB enhancements not present in the retail Japanese game, which provides additional incentive to play the patch on an SGB.

The voiceover has a timing-dependent blocking routine and has been notoriously difficult to emulate; many emulators (as well as Analogue Pocket) have historically had difficulty playing this voiceover correctly.

Pokémon Yellow, which also has voice samples, does not appear to have any issues on FXPAK Pro after quickly testing that game. It is unknown if other games compatible with the SGB have voice samples.