Most games: GM. A few: GS. Roland SC-7 / SC-55(MKII) is all you need. Some people prefer Yamaha / Korg or something else.

Was there any game made that utilized more than 32 polyphony?

You ask about minimum or maximum polyphony?

Just read http://www.homerecordinghub.com/midi-channels.html for a start to distinguish between channels/tracks and polyphony.
From this you see that as example with 1 channel and a polyphony of 1 a playing note would be cut if you play the next note. If you would have a polyphony of 2 then the first note would not be cut.
So having a higher polyphony allows notes to decay longer until the specific voice is reused. How many you need depends on your synth. There are soundfonts that require for playing a single note with one instrument several voices. While e.g. GSPlay shows how many channels played at the same time, it can not show what the maximum number of voices was that were used for playback.

elianda wrote:

You ask about minimum or maximum polyphony?

Well, both are interchangeable, i.e. minimum needed to cover all games, or maximum needed to be sufficient for all games (without dropping notes).

elianda wrote:

Just read http://www.homerecordinghub.com/midi-channels.html for a start to distinguish between channels/tracks and polyphony.
From this you see that as example with 1 channel and a polyphony of 1 a playing note would be cut if you play the next note. If you would have a polyphony of 2 then the first note would not be cut.
So having a higher polyphony allows notes to decay longer until the specific voice is reused. How many you need depends on your synth. There are soundfonts that require for playing a single note with one instrument several voices. While e.g. GSPlay shows how many channels played at the same time, it can not show what the maximum number of voices was that were used for playback.

Basically you can use 1 voice to create 1 note or many voices to create 1 note, and presumably using many voices would create a richer note. Is the later still considered polyphonic, even if only 1 note is generated?

BTW, here's a similar guide I read before that explained it well:

http://www.philrees.co.uk/articles/midimode.htm

So, essentially you can utilize high polyphony synths (e.g. 64), by using the higher number of voices available to produce lower polyphony music (e.g. 16) with fewer notes, but of a higher quality?

I suppose the question really is: How do I know notes are being dropped from the music being played back in games that use MIDI without the original reference recording?

256 is the answer.

If I understood the wikipedia entry, then the Roland SC-55 supports 24 voice polyphony. I also previously looked into this issue where testing the fluidsynth library settings for MIDI playback in dosbox. I recall trying different polyphony values against (a limited sample of) games in dosbox and decided that 256 voices, the fluidsynth default, was the lowest possible value without hearing a loss of sound quality. This is likely dependent on the specific values used for the other fluidsynth parameters and also on the soundfont as discussed above.

So about 256 voices for a Fluidsynth setup is about right. In this case with a soft synth, it's fairly trivial to increase polyphony by assigning more CPU resources.

What about hardware synths: Is it possible to daisy chain synths to increase polyphony, e.g. connecting MIDI Out to MIDI In using multiple synths? I recall reading somewhere that it's possible with some kind of MIDI 'overflow' setting using SysEx...?

You can send one instrument to one synth if you like.
I never tried using two of the same synths to increase polyphony, but i dont see why it wouldnt be possible.

Just a heads-up: XMPlay's MIDI plugin (the "MIDI Mixer" feature of the plugin) is quite handy for determining the maximum voices/polyphony for any given MIDI file (see attached screenie) 😀

Hmm a good hint, at least for SF2 sound fonts. But I guess it can also be used as raw estimation for other Synths (like Dream with 94B).

rfnagel wrote:

Just a heads-up: XMPlay's MIDI plugin (the "MIDI Mixer" feature of the plugin) is quite handy for determining the maximum voices/polyphony for any given MIDI file (see attached screenie) 😀

Thanks for the link as it made me revisit another MIDI player, GSPlay, and it also tracks maximum polyphony when playing back MIDI files.

Stojke wrote:

You can send one instrument to one synth if you like.
I never tried using two of the same synths to increase polyphony, but i dont see why it wouldnt be possible.

I've just done some tests and it is possible to daisy chain 2 identical synths to double polyphony. However, this looks like a feature that needs to be present for the synth as a SysEx function. Finally managed to get this to work with a function called MIDI Overflow with a SysEx utility called SendSX (tried MIDIEx and MIDICom, but never go these to work properly).

When setting up 2 synths, a master and a slave, you can listen to just the 'overflowed' notes on the slave synth, which sounds rather odd, or listen to all the notes on the master synth by simply using headphones. And essentially, these overflowed notes would've been lost notes not heard before, but because the slave synths audio output is routed back into the master synths input, you get to hear all the notes on the master synth.

However, to my surprise, I was expecting MIDI files that required more than 32 polyphony to have overflowed notes playing on the slave synth. Instead, what happened was even with MIDI files with less than 12 polyphony, some notes were overflowing into the slave synth. It looks like you can set maximum voices per MIDI channels 1-16 (so that the total doesn't exceed the maximum for the synth), and if this limit is exceeded on a particular channel, the notes oveflow into the slave synth.

With MIDI Overflow enabled, I can definitely hear some notes last longer in the composition, which I was oblivious to before.

I think the more modern cards do 1024 notes
allthough most of them are in software