Please add a Monophonic mode (Mono mode)

[average34]

I would like to use the monophonic mode in OPNMIDI to reproduce PC9821 music.
According to @Wohlstand, the "channels allocation" functionality for this is already implemented in libOPNMIDI / libADLMIDI.
Wohlstand/libOPNMIDI#109
So, please make it possible to switch the monophonic mode (channels allocation) on the GUI as well.

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こんにちは。
私はPC9821音楽の再現のために、モノフォニックモードをOPNMIDIで使いたいです。
@Wohlstand によると、そのための"channels allocation"の機能は既にlibOPNMIDI / libADLMIDIに実装されているそうです。
そのため、GUI上でもMonophonic mode (channels allocation) を切り替えられるようお願い申し上げます。

[Wohlstand]

Hello!

Again, it is NOT "mono", please don't confuse, and don't teach next generations by the wrong understanding, just learn how that's PROPERLY, and tell to everyone how it should be understanded properly.

You confused with "mono" and "stereo" concept that means one speaker output (or both speakers play equal content), and stereo when two speakers and each speaker might play unique content.

In the case of chip tune, the "mono" means that it's PC speaker opposed to "polyphony" (when one chip is able to play multiple tones at the same time), it only can play only one single voice (just a square wave) and can't play multiple tones: https://www.youtube.com/watch?v=U56KVYK5uTg&list=PLHzUTB8uEFlQ5JHQls_3lyLe3aJuE5lYr&index=1

The case when sound generation chip is polyphonic, then, the case is named channel allocation algorithm. Algorithm defines how notes will use chip's sound channels. Every chip's channel can only play only one tone. To maintain different behaviour, the use of channels can be done differently. One way - just simply use same chip's channel on same MIDI channel, that's how CMF files originally performed. That means, the releasing of previous note will be just shutted up by the new note immediately, turning it into the pseudo-"legato" effect. To respect the releasing of previous note, the same instrument will just cycle among all chip's channel and every new note gets played on the next channel. Because of that, you still hear releasing sound of previous note. It's how you play on different strings of the same guitar. You played one note on one string, and then played secodn note on second string. That's how the rest of late MIDI synthesizers worked. However, in some cases, to force the "legato" of notes and avoid effect of "different strings of same guitar", then algorithm choises the channel that has match by properties of the previously played instrument. And so, the next note will find the "sibling" and continue use the same channel without leaving releasing sound.