Yes, something is going wrong.

Normally, in a midi file, each track (which actually means nothing to MIDI, it's just a extra compartment in a midi file) is assigned to a single midi channel, then each channel (and the track involved) is assigned to a specific instrument/sound/drum kit/whatever. ALSO, the device that is receiving the midi (sound module, VST, etc) needs to be in POLY mode) so that it recognises the different channels.

Then, all the sound will appear, the group will sound like a group, the orchestra like an orchestra, etc..

But this does not happen of it's own accord, someone has to do something to set it all that way.

Midi files normally has that side of things set. It's rare that this is NOT set in the file. Whoever created the midi file probably went to a LOT of trouble to get it to sound correct. They would have noticed if it did NOT sound right.

Also, most multi-timbral sound devices default to polyphonic, rather than OMNI.

Are you sure that you haven't done something, maybe accidentally, to change something. Maybe the playback device/VST has got set to OMNI, maybe the channels have got cancelled from the midi data, or the Program Change instructions (that assign the different instruments, have got cancelled (or they might still be there but are being disregarded)?

One thing you could do is to take one of the midi files that is playing wrong, put it into a .ZIP file, and attach it to your next message. Then someone here can check it and make sure that the file is correct. If the file IS OK, then it's something else, but we're a step nearer sorting the problem out.

MIDI files always play fine for me!

REgarding your last para, there's still a problem when you play via Reaper? Do you need to add in the Channel assignments, or the specific instruments, or BOTH, to get it to come right? Those settings probably WERE there in the file originally, how have you lost them? What have you done with the files BEFORE you tried them in Reaper?

Maybe the midi files use certain Channels, but your sound device uses other channels, and you have to mess with settings to get any sound at all and maybe end up in OMNI? Or alter the midi file in some other way.

Nice would be a midi file before you do anything, then another copy when you find that something is wrong but just before you load it into Reaper.

Geoff

Can you upload a few sample files that have this issue? My guess is that the files in question were made and saved on a device that was configured but did not save this configuration info in the midi file. Without anything in the file to tell it what instrument to play, the player will typically default everything to Acoustic Grand Piano. I have seen files like this, usually more basic with only a couple of channels.

If this is the case and the files are separated enough internally (and you are using Windows), I have been working on an instrument switcher that you could try out. In this case, it will only work well if each instrument is on its own channel, as they are all piano at the moment.

To attach the files, you will need to put them in to a .zip file, as the forum does not allow unzipped .mid files.

This happens when a file is written for a specific synthesizer, and the settings are not made with standard MIDI messages but a SysEx parameter dump. Other devices cannot understand this.

Putting such a file on the internet makes sense only for very common devices, so it will probably be marked with the device name (SC-55, SC-88, etc.).

Ken says opening the MIDI file in "any media player" results in the notes all using the same instrument sound, but only specifically mentions Reaper. Perhaps we should ask exactly which media players Ken tried?

I don't use DAW software much, but I seem to remember things like the following:

If you drag and drop a MIDI file into DAW software that has an empty project already open, it might interpret that action to mean you want to import the MIDI file. In this case it might only focus on importing the notes from the MIDI file and ignore things like the tempo and instrument sounds specified in the MIDI file. Instead, try going to the File menu and using the Open command to open the MIDI file and see if the results are any different.

If that still doesn't help, your DAW software might require you to select or install a sound generator plug-in that produces instrument sounds compatible with General MIDI (or GS or XG).

It is possible that MIDI files might have been created without any PC (Program Change) commands. Specifically, VERY old midi files, from long before GM, when every device used different numbers for instruments available. So, no PC in the data, but a text message to say what the setting NEEDS to be.

Also, midi files created for a specific devices that defaults to certain settings, therefor will play correctly immed. My Roland card, LAPC-I, has default settings for some channels, so this would play correctly if the midi file expected the default instruments.

Geoff