Works in any *NIX
http://www.fluidsynth.org/

also see the built in stuff
https://www.kvraudio.com/forum/viewtopic.php?t=298008

Has anyone tried this with what I without knowing anything about this MIDI stuff assume are cheap chinese UM-ONE knockoffs, like this one for instance?

kaputnik wrote:

Has anyone tried this with what I without knowing anything about this MIDI stuff assume are cheap chinese UM-ONE knockoffs, like this one for instance?

Yes. Check first post!

kaputnik wrote:

Has anyone tried this with what I without knowing anything about this MIDI stuff assume are cheap chinese UM-ONE knockoffs, like this one for instance?

The knockoff USB adapters are usually missing parts, generally buffering and opto-isolation.
http://www.arvydas.co.uk/2013/07/cheap-usb-mi … ay-be-required/

They're a good deal if you're willing to buy the required parts and install them. They're less a USB MIDI adapter than they are a partly assembled kit with PCB, UART, and case.

PhilsComputerLab wrote:

Yes. Check first post!

Hah, missed that completely! Explains why it's not been discussed in length already 😁

gdjacobs wrote:

The knockoff USB adapters are usually missing parts, generally buffering and opto-isolation.
http://www.arvydas.co.uk/2013/07/cheap-usb-mi … ay-be-required/

They're a good deal if you're willing to buy the required parts and install them. They're less a USB MIDI adapter than they are a partly assembled kit with PCB, UART, and case.

Well, the modification work seems to be piece of cake, even think I've got suitable opto couplers stocked at home already 😀 Might try it as an experiment, it's not like it's gonna leave me broke if it's not good enough.

I got one of those cheap USB MIDI interfaces working with MUNT on a Raspberry Pi 3 last night. Adding the optocoupler and resistor is a piece of cake, and since I already had a scrap board with the needed parts it didn't cost my anything extra to do. For $4.99 I'm happy!

Having an Rpi plugged into my sound card MPU-401 port and working like an MT-32 is wild!

For more details, see my post here: Re: Emulating MT-32 on an RPi2

Took some photos of my cheap USB MIDI adapters from eBay. The PCBs are slightly different.

One looks exactly like yours though. I can see the spot for the optocoupler. R11 is removed on yours. And you put in R5. What's a good source for these parts?

R11 (which isn't really a resistor at all) would be to electrically couple the MIDI input to the serial encoder (the chip nicely placed under the black blob of doom), so it would need to be removed if adding the optocoupler (which is the MIDI standard of accepting input) -- i.e. it is either R11 or the optocoupler required for operation, not both. The optocoupler allows for electrical isolation between the output device and the USB-MIDI adapter (i.e. your host), which means avoiding grounding loops and unnecessary noise on the line, which could in some cases translate to missed or mis-interpreted notes/commands. Adding R5 is necessary for the operation of the optocoupler, and D1 should technically be populated too (with a diode), which also helps reduce transients and acts as a protection mechanism for incorrectly wired MIDI sources, but not strictly necessary.

https://www.midi.org/specifications/item/midi … l-specification

I use digikey for sourcing of pretty much any discrete (and integrated) electrical component I can think of... in Canada we have digikey.ca, not sure if digikey.com ships worldwide or only to US.

The second USB-MIDI adaptor you have pictured that has the MFM0880 chip appears to be a much nicer/less cheap one. Is there a difference in performance that you notice?

[edit] Digikey.com claims to ship to more than 170 countries worldwide!

Thanks for the pointers!

I haven't used them for a long time, since I got a Roland one. But I never had issues using them as a MIDI output, for let's say using DOSBox and connecting a real Sound Canvas.

It was only when I used MIDI input, that I noticed issues. But I can't remember which adapter I used. I never opened it before and just assumed they are identical.

I pulled my parts from a scrap board I got at work. We manufacture and service industrial devices that commonly use optocouplers so I lucked out there. If you're handy with a soldering iron, old modems are also a good source. You'll likely find a suitable current-limiting resistor (around 200 ohms) on a modem as well. Look for resistors marked 201 or 221, those are 200 and 220 ohm.

Over the years I've saved myself quite a bit of money re-purposing components from scrap boards, and it's good for the environment too! 😀

jaffa225man wrote:

Well, I've uploaded it for anyone interested. I'm not sure how long I'll leave it up, but feel free to download it while it's available. It did only take last night through to this afternoon to upload it (albeit with nothing else using the connection because it probably would have timed out and needed to be started from scratch otherwise). As said, I don't know if it will work yet, but here it is, gdjacobs' munt raspbian image upgraded to jessie for the pi 3: https://drive.google.com/file/d/0B2uObEBH_jRH … iew?usp=sharing
Anyone using it will still need to use gdjacobs' method for installing the roms, etc.

Thanks again for everything gdjacobs!

Any updated images available for rpi3?

ahtoh wrote on 2019-08-02, 14:37:

jaffa225man wrote:

Well, I've uploaded it for anyone interested. I'm not sure how long I'll leave it up, but feel free to download it while it's available. It did only take last night through to this afternoon to upload it (albeit with nothing else using the connection because it probably would have timed out and needed to be started from scratch otherwise). As said, I don't know if it will work yet, but here it is, gdjacobs' munt raspbian image upgraded to jessie for the pi 3: https://drive.google.com/file/d/0B2uObEBH_jRH … Q-wfF4lSwtS3qPw
Anyone using it will still need to use gdjacobs' method for installing the roms, etc.

Thanks again for everything gdjacobs!

Any updated images available for rpi3?

Sorry, no, I ran out of steam since then. It was good enough for me, but my plan was in making it automatically configure midi/audio hardware based on the devices available, but I never packaged it to upload. I got distracted by fluidsynth skipping notes while playing GS test file, and just let it languish. It doesn't help that I have the real devices and the pi3 just seemed a bit too slow in comparison. Now who knows about the pi4, but it might be better to wait for a future generation that doesn't balk at all. I do, however, feel pressured enough to upload my almost finished rpi3 version when I have time.

ahtoh wrote on 2019-08-02, 14:37:

Any updated images available for rpi3?

At last, I have finished it: https://drive.google.com/file/d/1QYQmFp8zLyxl … iew?usp=sharing

Sadly, the 7-zipped image is about three times the size of my previous version, which is unusual as my edits themselves don't take up much space. It's probably the /usr/src/linux directory that I compiled the custom kernel in. Anyway, this new 2.9GB image prompted me to conserve space by removing the prior release.

This image boots graphically and runs the current (2.6.2) mt32emu-qt GUI by default. MUNT may also be restarted or run again with the keypress ctrl-alt-m. Likewise, to switch to Qsynth (which is setup for GS by default), the keypress ctrl-alt-s will close MUNT and run it. So, feel free to switch between the two with those key combinations, or even restart either program with their own keys. Another useful keybinding is to shutdown the raspberry pi, before unplugging it, by using ctrl-alt-delete.

Don't forget, it will still need the MT-32/CM-32L ROMs added in /usr/share/mt32-rom-data/. If it would help, I wrote a simple ip-address-show-dialog.sh script that can be run from a terminal emulator (right click the empty desktop) so you can find the ip address (the four numbers separated by periods between "inet" and "/"). I changed the owner of that mt32-rom-data directory to "user" and made user's password simply "user" (without quotes), so it can be copied to with SCP-supporting programs like winscp or putty (Login: user, Password: user). When done, feel free to disconnect the pi's ethernet, or remove the user password with the terminal emulator with "sudo passwd -d user" (without quotes).

This hasn't changed between releases, but if you want to avoid MUNT's clicks and pops of the raspberry pi's standard audio output, I recommend connecting a usb soundcard before booting the pi. My latest version should automatically configure both programs to be using it without your intervention. I have only tested it on my Edirol UA-4FX, but think any Roland/Edirol UA device should work, assuming they're supported by Linux kernel 4.9.27. With my UA-4FX I have audio output as well as MIDI input for use with this on a single USB port. As mentioned in my previous post, Qsynth is a bit slow on the pi3 even with a better audio interface, so I'd probably just use this reliably for MUNT anyway.

I hope this helps, and happy music playing!