The MMC5 sound docs do not discuss how to mix the MMC5 sound channels with the standard ones. Any suggestions on how to do the mix?
What's ambiguous about
Sound output is equivalent in volume to the corresponding APU channels, but the polarity of all MMC5 channels is reversed compared to the APU.
?
Thanks. I guess I was looking for a math formula with the right constants, but that single line seems to convey what to do.
On a related topic, are the MMC5 sound channels disabled in the US version of Castlevania III? Or, more importantly, are the standard 5 channels used differently in the US vs the Japanese version? Meaning, even if they could be enabled, should they be enabled in the US version?
The sound output of the MMC5 isn't physically connected to anything for Castlevania III.
In software the sound is enabled through $5015. Two minutes with a debugger determines that Castlevania III doesn't write to $5015. So, if you initialize your MMC5 sound enable to off, there is no special concern that Castlevania III will turn it on and start playing rogue audio through the unconnected lines.