MT-32 ROMs with the P330 receiver

Munt (MT-32) is one of the receivers for the rear P330 MPU-401 port. The emulator plays it internally, and a host MIDI destination is different. The audio of Munt goes into the output of the machine. Thus you do not need a second application, and you do not need a virtual MIDI cable.

Munt needs two ROM images from a Roland MT-32 or a Roland CM-32L: a control ROM and a PCM ROM. IzarraVM does not include Roland ROMs. It does not download them, and it does not distribute them. See Which ROM files does Munt need? for the images of each machine. This page describes what the loader accepts after you have a set.

What the loader accepts

The two boxes in the config modal have the labels MT-32 control ROM and MT-32 PCM ROM. But neither box is a fixed slot. Each box accepts one ROM file, or the folder with the ROM set. The loader identifies an image by its content, and not by its file name. Thus:

  • The file name is not important. MT32_CONTROL.ROM and MT32_PCM.ROM load. A set with firmware version names loads. A set with other names loads. The loader asks the synthesizer library to identify each file. It does not read the name.
  • The box is not important. The set loads if you put the control image in the PCM box. The simplest method is to give the same folder to both boxes.
  • The loader joins split half-images. The loader cannot identify a ROM in two halves one file at a time. Thus it tries the unidentified files in pairs, in both orders, with the files beside them. For this reason, a folder frequently loads when two file names do not.
  • The loader searches the folder of the set. If your selection is not a complete set, the loader also scans the folders that hold your selection. It always tries your selection first.

Procedure

  1. Put the ROM set in its own folder, with no other file in it. The loader also scans a folder with other files, but that scan stops after the first 64 files.
  2. Open the config modal from the control panel, and find the Audio section.
  3. Give the set to MT-32 control ROM and MT-32 PCM ROM. The folder in both boxes is sufficient. The two file names are also sufficient if each file is a whole image.
  4. Select Munt (MT-32) as the P330 MIDI receiver. You can select this entry only after both boxes name a file or a folder that exists. Before that, the entry shows Munt (MT-32) (missing ROMs). The two ROM boxes stay on the screen with each receiver.
  5. Press Accept, and read the status line below the selector. Ready means that the synthesizer opened.
  6. Start the game, and select MT-32, LAPC-I, or MPU-401 at port 330.

Automatic discovery

If both boxes are always empty, IzarraVM looks one time at startup. It looks in the state directory that holds cmos.bin and izarravm.conf. It takes the first of these that it finds:

  • MT32_CONTROL.ROM with MT32_PCM.ROM, or CM32L_CONTROL.ROM with CM32L_PCM.ROM, directly in that directory. The name check ignores the letter case.
  • A sub-folder with the name mt32, cm32l, roms, or mt32-roms. This check also ignores the letter case. IzarraVM gives the full folder to the loader. Thus the files in it can have any name, and they can be split halves.

This function is for a set that you copy into that directory. It is not a search. It does not operate under --portable, and it looks in no other directory. It does not change a path that is already in a box.

Accept is also the retry control. You can correct a set outside the emulator. For example, you can copy an absent file into the folder, or change the name of the folder. Press Accept again to load the corrected set. A change in the panel is not necessary, and a restart of the machine is not necessary.

When the set does not load

The status line gives the requirement that failed. It does not give a general failure message. The log lists each file that the loader tried.

Status line What it means
Select both MT-32 ROMs. P330 output is silent. One box or both boxes are empty. The receiver is Munt, thus the guest MPU-401 continues to answer, but nothing plays.
A selected MT-32 ROM path does not exist. A box names a file or a folder that is not there. Look for a set that moved or that has a different name.
No MT-32 control ROM was recognised. Point either box at the ROM set's folder. No file was a control image. Usually the set is in halves, and you named only one file. Name the folder, and the loader can join the halves.
The control ROM loaded but no PCM ROM was recognised. Add the PCM image to the set. The set is not complete. The PCM image is not in the files that the loader searched.
The control and PCM ROMs are from different machines. Use one matched set. The loader identified both images, and the synthesizer refused the pair. One example is an MT-32 control ROM with a CM-32L PCM ROM. Use two images from one machine.

If the loader does not recognize one file, the message names that file. This is more useful than a list with one entry.

Notes

  • The P300 wavetable is independent. A change of the P330 receiver does not change the internal daughterboard. Each section has its own status line, thus a ROM problem cannot hide a failed SoundFont. A change of the receiver sends all-notes-off to the previous receiver.
  • MT-32 is not General MIDI. A game from approximately 1988 to 1992 with an MT-32 option uses the instrument layout of the MT-32. A General MIDI score through an MT-32 gives the incorrect instruments. For a General MIDI score, use the internal wavetable at P300, or a host receiver. See How to use your own MIDI player.

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