An official MT32pi consolidated thread?

[seastalker]

What do the admins here think of a place or category on the site dedicated to the MT32pi project?

With MT32pi kits on the ko-fi site [Source RetroRGB], would it not be great to visualize all the separate MT32pi posts in one dedicated place on the site?

I'm still learning about the project and don't know which place to piggyback on with my questions? I'm still learning about the project but know much about the MT32.

For the pi version, is any pi laying around ok or is anything over a pi2 zero overkill? I have a pi3 but don't know if it will fit the various cases out there (or fit but look funny). I read about a lite version too. Short cable lengths are suggested too. Hopefully some comprehensive 'de-MiSTifying MT32pi' tutorial and shopping list video will emerge at some point focused not only on the MiSTer but it's use with original retro computers too.

[DevilHunterWolf]

I would highly recommend starting with the official GitHub page as there is a lot of information already there on Pis, configuration, etc. https://github.com/dwhinham/mt32-pi

But to break it down a bit, there are two main things that determine if a Pi is good enough for MT32-Pi: CPU power and RAM size. CPU power is the most important one. Not enough power and the Pi can't handle the software to recreate a synthesizer. That's why single core Pis are a no go. A Pi 2 sort of gets in as minimum with the caveat that you can't have it output as high of quality of audio. Pi 3 and above (which includes the Pi Zero 2) have a strong enough CPU to run most features of MT32-Pi. If all you're interested in is recreating the Roland MT-32, you can stop right here. Any Pi good enough to run MT32-Pi is good enough for MT-32 recreation using Munt. But, it gets a bit more interesting and complicated as soon as you look into the other major feature of MT32-Pi: FluidSynth.

FluidSynth allows you to create General MIDI based synthesizers. These can be based off of real hardware like the Roland Sound Canvas SC-55 or fictional creations like one based off the instrumentation of the Sega Genesis. This is also where RAM comes into play. The files needed to recreate a Roland MT-32 can be done with any compatible Pi but it's these General MIDI recreations that might require more RAM. To sum up, these are done with SoundFonts or specifically .sf2 files. File size and RAM requirements are directly related. The size of the SoundFont has to fit in the RAM of the Pi, minus some for the MT32-Pi software to run. A Pi 3 Model A (the smaller one) or Pi Zero 2 have 512MB of RAM meaning any MIDI recreation has to fit under that size. For many out there, this is plenty enough RAM. The majority of sounds I've been interested in are anywhere from just 1MB in size to all the way up to 265MB. For a lot of people, 512MB of RAM will be plenty especially if they're interested in just era appropriate General MIDI sound.

There are a few notable SoundFonts out there that are larger, though. As an example, the Timbres of Heaven 4.0 comes in at a size of 419MB. It fails to load on my Pi Zero 2 based MT32-Pi. It's just a bit too big to fit into the RAM with the software. Timbres of Heaven is more an example of an outlier rather than what's common but if you want to be able to throw any size SoundFont at an MT32-Pi build, you need 1GB or more of RAM (the only reason a Pi 4 2GB would be required over other Pi choices). This is something down to personal preference, though. Some enjoy Timbres of Heaven but I have yet to be impressed with its sound compared to other smaller SoundFonts I've found. I personally prefer either UGM v1 beta or OmegaGMGS2 SoundFonts for higher quality General MIDI and they run with no issues on my 512MB Pi.

And that's pretty much all the background someone using it for MiSTer needs to know. The super short cord requirement is so that the connection is strong since it's one USB cable for both power and data connection. Once you're talking about original retro computers, that's a different discussion. MT32-Pi is only just a swap out for a hardware synthesizer. It's a different rabbit hole having to connect one to actual hardware and not anything someone using a MiSTer build has to worry about.

[softtest9]

About soundfonts, I discovered that the default soundfonts on Sound Blaster cards are just soundfont files that can be extracted from the driver disc. This applies even to late cards like the X-Fi series.

[seastalker]

Thank you DevilHunterWolf for a perfect answer. It really helped a lot! So I can use my Pi 3B (non-plus) for now, though depending on the hat/case it may extend out a bit. It has 1gb of ram so I don't need a 4 for it if I so happened to like and want to enjoy Timbres of Heaven, yes?

When I want a separate pi dedicated to the project, a Model 3A (square form factor) or Zero 2 will work fine, albeit lose the Timbres of Heaven and other large SoundFont compatibility I may find I don't need. Do I have it all correct?

I now see that cases are being designed to match the form factor of the various pi models (the square 'A' and the rectangular small Zero). Anyone have pros and cons to report on aesthetics or preferences of one style vs the other?

[DevilHunterWolf]

Thank you DevilHunterWolf for a perfect answer. It really helped a lot! So I can use my Pi 3B (non-plus) for now, though depending on the hat/case it may extend out a bit. It has 1gb of ram so I don't need a 4 for it if I so happened to like and want to enjoy Timbres of Heaven, yes?

When I want a separate pi dedicated to the project, a Model 3A (square form factor) or Zero 2 will work fine, albeit lose the Timbres of Heaven and other large SoundFont compatibility I may find I don't need. Do I have it all correct?

I now see that cases are being designed to match the form factor of the various pi models (the square 'A' and the rectangular small Zero). Anyone have pros and cons to report on aesthetics or preferences of one style vs the other?

From what I've experienced and what the GitHub specifies about RAM size, 1GB of RAM should be fine for Timbres of Heaven. The amount of RAM needed by MT32-Pi shouldn't change between Pi models so there's plenty for Timbres of Heaven. The page for SoundFonts specifically mentions RAM only being an issue for SoundFonts larger than 1GB. https://github.com/dwhinham/mt32-pi/wik ... SoundFonts I believe the wiki assumes the standard 1GB Pis are being used so you should be good. I would have thought the 512MB Pi Zero 2 would have been fine but not from my personal experience. Timbres of Heaven works on my PC without a problem and is recommended on the MT32-Pi page so I doubt it's an issue with the SoundFont.

The standard Pi hat should work with all supported models of Pi. I think even the Pi Zero 2 was initially tested with the same hat since the GPIO pin layout hasn't changed in the recent Pis. As far as pros and cons, there's not much functionally different between the older Pi 3 Model A hat and the new official Zero 2 hat except for the added volume wheel. Even without a wheel, the default audio level of the MT-32 and each individual General MIDI SoundFont can be adjusted in the MT32-Pi configuration file. So while the wheel is a nice to have feature, it's not required if one SoundFont is too loud or if you need to give a boost to just one. You just change it in the config file. Even buttons and an LCD screen are technically optional with a MiSTer. The menu in the MiSTer OSD for MT32-Pi allows you to display what the LCD screen would have shown and can act as the buttons which is why the "lite" version with nothing extra on it exists for MiSTer.

The only potential consideration between hats is maybe the use case. This is where my inexperience with this is going to show but I don't know if the MiSTer specific hat will work flawlessly with other devices. The official Pi Zero 2 hat is not device specific so it was built ready to accept MIDI input and standard audio output if it's being used as just a MIDI synthesizer. I would think this could still be done on the MiSTer version hat since the Pi 3 Model A and other models have a 3.5mm jack and at least 1 USB port but I don't have experience with other Pis and MT32-Pi to say this confidently. Hopefully someone has already tried this (either on the forums or in a video somewhere) and can give you a more concrete answer to that. If it can, I'd say it's down to just size consideration.

[DevilHunterWolf]

Just wanted to add some additional information from my own testing. I picked up the MT32-Pi hat from MiSTerAddOns and used it with a Pi 3 B+ I had around. Works with the MiSTer as expected and with some configuration changes it can be used as a regular MIDI synthesizer. I hooked mine up to a MIDI capable keyboard and I was up and running pretty quick for both MT-32 mode and SoundFonts. Used one of the recommended USB MIDI cables, the Roland UM-ONE mk2. The only real issue I had was the 3.5mm audio out from the Pi was **very** quiet. I had to crank up the volume both on the MT32-Pi and a sound system to be a decent audible level. A proper DAC for audio output might solve this but I haven't been able to try this yet. Timbres of Heaven is still not one of my go to choices but it did work on the Pi 3 B+'s 1GB of RAM.

Otherwise, it seems like any version of the hat is going to offer the same capabilities. The exception, of course, being the "lite" hat with no buttons or screen. No buttons means you have to rely on the MiSTer's menu to change SoundFonts and that's limited to just 8. Having actual buttons to use means you can cycle through the entire list, not just entries 0 to 7. Even as I've been testing out SoundFonts, I find 8 is good enough. More is nice but in my opinion a lot of choices either end up sounding too much alike or too limited and gimmicky to be enjoyable for longtime use. They're fun to have for messing around on a keyboard or playing MIDI files on a computer but I wouldn't necessarily play a game using some SoundFonts.