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First post, by fsmith2003

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I have a Pi 3B+ that I am trying to use MT32-Pi on. Are there step by step instructions other than what is on the quick start section of the creators github? I followed those and nothing is working. Here is what I did:
- I copied the contents of the zip file downloaded from the github page onto the root of the Pi's sd card.
-I placed the MT32 roms in the roms folder of the sd card
-I plugged in the UM-One into a USB port of the Pi and plugged in speakers to the headphone jack.
-I hooked up the other end of the UM-One to my vintage PC's midi port.
- When turning on the PI none of the LED's light up on the UM-One and there is no sound coming out of the speakers when playing midi from the vintage PC.
-I confirm this same setup works using Munt on a regular PC without the pi so I know the configuration is correct on the UM-One cable itself.

Anyone using this same configuration and have some hints of how to get it to work?

Reply 1 of 12, by FISHERMAN

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i am stuck in the exact same position on a RPI3A with UM-ONE cable ..i have send an email to Edu Arana asking for some clarifications.

following the instructions from github i did some changes :

usb = on
gpio_baud_rate = 31250
gpio_thru = off
output_device = i2s --> no output 🙁
sample_rate = 96000
chunk_size = 512
i2c_dac_address = 4c
resampler_quality = good
midi_channels = standard
rom_set = old
type = ssd1306_i2c. --> oled screen now working OK

if i use a simple Midi cable then on the oled screen i get the messages "frame error" & "Midi unexp error" and sound is distorted , while if i change to UM-ONE cable i get no sound and no messages on screen..

I also confirm that running rpi3b+ with muntPi worked pefectly with the same pc setup and um-one cable.

Reply 3 of 12, by Jo22

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MT32Pi is really neat. I tried a cheap USB cable on the reception side first, but soon realized that the MIDI interface was poor - no opto-coupler, just resistors (bad design!).
Because, with different ground connections, this setup almost begs for a failure.
So I made a cheap MIDI-In using an underpowered, slow opto-coupler and finally got music in Gateway.

Here's a quick video of it, along with a cheap tube amp that I made from spare parts.
If done correctly (fast opto-coupler), the little stuttering should fixed, too :
https://m.youtube.com/watch?v=Y43kYMGZhKk

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"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 4 of 12, by gdjacobs

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FISHERMAN wrote on 2020-10-17, 21:47:
i am stuck in the exact same position on a RPI3A with UM-ONE cable ..i have send an email to Edu Arana asking for some clari […]
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i am stuck in the exact same position on a RPI3A with UM-ONE cable ..i have send an email to Edu Arana asking for some clarifications.

following the instructions from github i did some changes :

usb = on
gpio_baud_rate = 31250
gpio_thru = off
output_device = i2s --> no output 🙁
sample_rate = 96000
chunk_size = 512
i2c_dac_address = 4c
resampler_quality = good
midi_channels = standard
rom_set = old
type = ssd1306_i2c. --> oled screen now working OK

if i use a simple Midi cable then on the oled screen i get the messages "frame error" & "Midi unexp error" and sound is distorted , while if i change to UM-ONE cable i get no sound and no messages on screen..

I also confirm that running rpi3b+ with muntPi worked pefectly with the same pc setup and um-one cable.

Do you have an external DAC? I2S will output serial data via the requisite pins and needs an external device wired to the GPIO header to decode it.

All hail the Great Capacitor Brand Finder

Reply 5 of 12, by Jo22

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Is that Roland cable correctly connected?
Re: Roland MT-32, CM-32L + General MIDI for $50 Building a MIDI box

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 6 of 12, by FISHERMAN

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Finally I was not doing anything wrong ....updated to o.62 and voilas!! Happy gaming

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Reply 7 of 12, by Jo22

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FISHERMAN wrote on 2020-10-24, 20:35:

Finally I was not doing anything wrong ....updated to o.62 and voilas!! Happy gaming

I can confirm, no lame excuse.
USB MIDI was broken for a moment (6 to 6.2).

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"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 8 of 12, by fsmith2003

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Everything is working great now! I did just obtain a 128x32 LCD for the Pi. It is working great as well but it did cause me to notice one thing. It shows the volume is set at 72 within MT32-Pi. Is there a way to adjust this in the config file or otherwise? I have noticed the volume is much quieter coming from it than my other computer sounds from the sound card.

Reply 9 of 12, by Spikey

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The MT-32 has a low volume output, so increasing from 72 to 100 will likely help, but not enough (28/72 = ~40% louder than currently) . If it's based on MUNT, maybe you can enable gain?

Reply 10 of 12, by d0pefish

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Hi, I'm the author of mt32-pi.

Sorry about the broken USB; it doesn't get tested as often as GPIO MIDI so unfortunately I missed it!

Re: the volume - it should always be 100 when you first boot up. Some game/MIDI song will have lowered it via a SysEx message, I imagine.
The volume will be controllable via a rotary encoder soon.

Reply 11 of 12, by fsmith2003

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d0pefish wrote on 2020-11-01, 15:10:
Hi, I'm the author of mt32-pi. […]
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Hi, I'm the author of mt32-pi.

Sorry about the broken USB; it doesn't get tested as often as GPIO MIDI so unfortunately I missed it!

Re: the volume - it should always be 100 when you first boot up. Some game/MIDI song will have lowered it via a SysEx message, I imagine.
The volume will be controllable via a rotary encoder soon.

Yes I did notice it was 100 on start up but most games will lower it themselves. A manual rotary knob would be a great addition!

Reply 12 of 12, by Jo22

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d0pefish wrote on 2020-11-01, 15:10:
Hi, I'm the author of mt32-pi. […]
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Hi, I'm the author of mt32-pi.

Sorry about the broken USB; it doesn't get tested as often as GPIO MIDI so unfortunately I missed it!

Re: the volume - it should always be 100 when you first boot up. Some game/MIDI song will have lowered it via a SysEx message, I imagine.
The volume will be controllable via a rotary encoder soon.

Hi - Thanks a lot for browsing by and for your help! 😎

I'd like to take the opportunity to thank you (in the name of many here, I guess) for the excellent work.
Even though I'm one of the few people who own both a MT-32 and a CM64, I have a lot of fun tinkering with MT32-Pi and my Raspberry Pis.

I'm currently doing a little project that involves installing a Raspberry Pi (w/ MT32-Pi) in the chassis of an old alarm clock.
When I tried running it on a Pi 2, nothing happend at first, but it was my fault. 😅 My USB MIDI interface was plugged in another port,
so the MIDI I/O in Raspbian changed. Editing my DOSBox config and changing "midiconfig=24:0" to "midiconfig=20:0" fixed it.

Edit: Setting chunk size to 256 and disabling resampling seems to improve music playback on the Pi 2 in my copy of Frederik Pohl's Gateway.

IMHO, I think it is very cool that MT32-Pi still runs on the old Pi 2. Even though doing so is on the very limit (almost borderline).
Because, the Pi 3 has a power managment chip that easily breaks if 3.3v line gets a short (on the GPIO).
So an used, second-hand Pi 2 has a higher chance of functioning than a Pi 3, I assume.
Also, some late Pi 2's seem to have the same ARM chip as the Pi 3 (speaking under correction, though).

Speaking of the Pi 2.. I use a not so quick opto-isulator on the GPIO interface, a CNY17-2 in diode-"mode" only to make things faster.
It's not ideal and I experience some stuttering, perhaps some buffering issues (resampler_quality = fastest).

It seems to me that changing to a CM32L ROM set reduces this stuttering a bit, but still causes hanging notes.
That being said, not sure if this really has an effect or if it is just my imagination.
I must check with a fast optocoupler next time, if I can get one (my local seller only has common types).

Anyway, that's enough I guess. I don't mean to hijack fsmith2003's thread. 😅
Just wanted to provide some feedback.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//