jheronimus wrote:

I'm thinking about getting myself a Roland MT-32 for a 486 DOS gaming machine. I'm currently thinking about going the AWE64 CT45 […]
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I'm thinking about getting myself a Roland MT-32 for a 486 DOS gaming machine. I'm currently thinking about going the AWE64 CT4500 + SoftMPU + MT-32 route and later maybe "upgrade" to a CT-1747-based AWE32 or SB16. My final goal is to have the versatility of SB+OPL3+MT32+GM in a single machine without having to employ a second PC for munt emulation or changing ISA cards every time I want to play a different game. I am mostly playing RPGs like Lands of Lore/Ultima Underworld, DOOM and Duke Nukem-based shooters, some quests like The Dig and Gabriel Knight.

A couple of questions:

1) how accurate/bug-free is SoftMPU? I'm just wondering: if it's 100% issue free, why do people still insist on getting an MPU-401 in most threads and YouTube videos I've seen?
2) how resource-hungry is it? I'm going to use it on a 486dx2@66/12 MB RAM machine with no L2 cache running DOS 6.22 if that matters.
3) I know there is a Roland's MT2GM tool to remap MT32 to general MIDI. How accurate is that vs a SC-55?
4) provided I don't use a real MPU-401, I just need a SoundBlaster, a GamePort-Midi cable and a MT-32, right?

Thanks!

Well, I'm planning on eventually installing my SBC RPi2 running Munt and Timidity in a 5 1/4 inch bay on my PC. Would that be interesting?

gdjacobs wrote:

Well, I'm planning on eventually installing my SBC RPi2 running Munt and Timidity in a 5 1/4 inch bay on my PC. Would that be interesting?

Wouldn't you need a USB-MIDI adapter? I mean, a $50 adapter + $35 for an RPi comes pretty close to an actual MT-32.

To answer your questions, in order
1) Fairly good from my experience. Some games will give you problems for other reasons, but the handful of intelligent mode games I own all worked. Check out the compatibility thread for more details. Note that many games (Ultima Underworld included) only use UART mode, so they don't even need softmpu. Later GM games like Doom and Duke definitely don't.
2) Can't comment in this; my machine is a Celeron. A 486 is probably good enough.
3) It's serviceable. Doom sounds pretty good, other games less so. You should probably just use the AWE64 for GM games unless you have one with no AWE support.
4) Yes 😀. Plus audio cables/adaptors to actually hear the MT32 output, either connected to line in, or to an aux port on your speakers (if they have it).

jheronimus wrote:

gdjacobs wrote:

Well, I'm planning on eventually installing my SBC RPi2 running Munt and Timidity in a 5 1/4 inch bay on my PC. Would that be interesting?

Wouldn't you need a USB-MIDI adapter? I mean, a $50 adapter + $35 for an RPi comes pretty close to an actual MT-32.

The RPi can process MIDI in/out using the UART pins and a standard adapter to convert to a current loop with optical or galvanic isolation. This adapter is a simple circuit to build. It can also emulate GM/GS/XG without Windows which an AWE64 can't.

Yes, simply hook up a MAX232 to Raspberry:

And Cable: (If you want use a Module with Dosbox..)

The DB-9 to DIN cable is not by any means the proper way to connect RS232 level signals to MIDI signals. I highly recommend not to build that, ever.

MIDI uses current loop while RS232 uses positive/negative voltages. Sure it might work in some cases but not 100% compatible. Not if the MIDI out on the other device uses open collector driver, which is perfectly normal in MIDI. And this lacks the isolation between devices.

In fact if connecting MIDI out to Raspberry Pi in or other logic level UART does not require much other than an optoisolator and some resistors. There is no need for MAX232 as it is meant for RS232 level signals on DB-9 ports.

Jepael wrote:

In fact if connecting MIDI out to Raspberry Pi in or other logic level UART does not require much other than an optoisolator and some resistors. There is no need for MAX232 as it is meant for RS232 level signals on DB-9 ports.

These were exactly my thoughts! Even a cheap USB-Serial adapter would be safer, as it is often using +5V (+3.3v)/0V levels anyway.

Jo22 wrote:

These were exactly my thoughts! Even a cheap USB-Serial adapter would be safer, as it is often using +5V (+3.3v)/0V levels anyway.

That's a good idea. I don't know how the Raspberry integrated UART works, but at least USB-Serial adapters with FTDI chipset can be set to all kinds of exotic baud rates directly, so 31250 should be no problem. Many people can already have these "Raspberry Pi Uart to USB" cables already, but sometimes they only have 3 wires and are set to 3.3V levels. If you find such a USB serial converter cable with 5V logic leves plus fourth wire for 5V output, that would be perfect for the job, as it is easier to make a MIDI interface with 5V than 3.3V, although they did update the specs because 3.3V is so common these days.

Downside is that USB-serial adapters may have large buffers and long timeouts in their drivers, so at least those settings are easy to change on Windows. And it would look like a normal serial port to OS, instead of MIDI port. USB to MIDI adapters are not that expensive anyway.

jheronimus wrote:

[...]
3) I know there is a Roland's MT2GM tool to remap MT32 to general MIDI. How accurate is that vs a SC-55?
[...]

It will be disappointing : better than no GM at all but a real SC-55 will be way better with GM stuff.

Jepael wrote:

Jo22 wrote:

I don't know how the Raspberry integrated UART works, but at least USB-Serial adapters with FTDI chipset can be set to all kinds of exotic baud rates directly, so 31250 should be no problem.

with pi/pi1/pi2, you can use its uart on gpio BUT you have to set some config parameters that init the chip on bootup to change its uart clock frequency so you can get 31250 within baud error%.

for pi3, well they switched the uart on the GPIO to the secondary uart (which was not used on pi1/pi2) and moved the original uart to bluetooth/wifi.
so on pi3 you have to remap the uarts on gpio with the dts/dtb files in the bootup config. doing this will loose the ability to use bluetooth+wifi.

Jepael wrote:

The DB-9 to DIN cable is not by any means the proper way to connect RS232 level signals to MIDI signals. I highly recommend not to build that, ever.

MIDI uses current loop while RS232 uses positive/negative voltages. Sure it might work in some cases but not 100% compatible. Not if the MIDI out on the other device uses open collector driver, which is perfectly normal in MIDI. And this lacks the isolation between devices.

In fact if connecting MIDI out to Raspberry Pi in or other logic level UART does not require much other than an optoisolator and some resistors. There is no need for MAX232 as it is meant for RS232 level signals on DB-9 ports.

Precisely. The MAX232 provides level shifting which is gratuitous in this application.

BloodyCactus wrote:

for pi3, well they switched the uart on the GPIO to the secondary uart (which was not used on pi1/pi2) and moved the original uart to bluetooth/wifi.
so on pi3 you have to remap the uarts on gpio with the dts/dtb files in the bootup config. doing this will loose the ability to use bluetooth+wifi.

I was not aware of this. Furthermore, it appears that the UART can only be adjusted by changing the CPU core clock on the Pi 3. Thumbs down!

gdjacobs wrote:

I was not aware of this. Furthermore, it appears that the UART can only be adjusted by changing the CPU core clock on the Pi 3. Thumbs down!

if you remap the original uart back on the pi3 using the dts/dtb files (dtoverlay= etc), its back to how it was on the pi1/pi2 so all is not lost (unless you want to keep wifi+bluetooth)

BloodyCactus wrote:

if you remap the original uart back on the pi3 using the dts/dtb files (dtoverlay= etc), its back to how it was on the pi1/pi2 so all is not lost (unless you want to keep wifi+bluetooth)

Fair enough, but WIFI and BT would be useful for a drive slot mounted, Pi 3 based MT32/CM-32L/SC-55/MU80 emulator. 😀