Hi. The OPL3 doesn't do understand MIDI, it needs a synthesizer driver to translate MIDI data to OPL3 commands.
MPU-401 is just a serial port that is wired to the WaveBlaster header and the Game/MIDI port.

DOS games used middleware drivers such as Miles Sound System or iMUSE to playback MIDI on the OPL3 chip.

https://en.wikipedia.org/wiki/Miles_Sound_System
https://en.wikipedia.org/wiki/IMUSE

Windows 3.1x had various FM drivers depending on the sound card driver.
The driver diskettes of ProAudioSpectrum 16 and SB16 (later) had used Voyetra Super SAPI OPL3 MIDI driver, for example.

If you really want to playback MIDI via OPL3 on plain DOS, please have a look at SEAL/2.
It's a GUI for DOS that uses Allegro library. It has a player that works.
Example: https://www.youtube.com/watch?v=JFo3luv-ByA

Drahel wrote on 2025-05-19, 11:15:

Hi, can I directy play .mid files under dos through OPL3 (Yamaha YMF-262) on my Sound Blaster 16 CT1770 card?

I tried software called megamid under DOS, but it gives no sound. I have card configured and it's working (midi playback on windows works through "internal OPL2/3 synthesis") MPU-401 on address 330. I select this adress in megamid, but it does not work. I doesn't have WaveTable or ASP connected. Please help

You can also try DosMid. By default it uses OPL/FM synths for Midi playback (the used output mode can be set in DOSMID.CFG):
Re: DOSMid - an open-source MIDI player for DOS

Thanks for replies. I will try SEAL/2 and DosMid later. But now I'm curious, what kind of hardware device I will need to use Megamid software? I recently saw a video with someone playind .mid files with this software...

Drahel wrote on 2025-05-19, 12:12:

Thanks for replies. I will try SEAL/2 and DosMid later. But now I'm curious, what kind of hardware device I will need to use Megamid software? I recently saw a video with someone playind .mid files with this software...

MegaMid only supports the classic Roland MPU-401 and Sound Blaster MIDI ports (maybe also serial port?). This means you need either a sound card with an integrated wavetable synth (that is available through an emulated MPU-401 port), or a waveblaster card attached to your sound card's waveblaster port, or an external Midi synth attached to the joystick port through a Midi converter cable.
In case of SoundBlaster 16 there is no integrated wavetable synth so in order MegaMid to work you either need a waveblaster card or an external Midi synth.

Yeah, that was right, DosMid works with parameter /opl enabled. Thanks for this. But, is there any cheaper alternatives for wave blaster daughterboard? Also, if I sell my card and bought for example CT2760, which is AWE32, does it mean, that wavetable is onboard already and I will be able to use it?

Drahel wrote on 2025-05-19, 19:03:

Yeah, that was right, DosMid works with parameter /opl enabled. Thanks for this. But, is there any cheaper alternatives for wave blaster daughterboard? Also, if I sell my card and bought for example CT2760, which is AWE32, does it mean, that wavetable is onboard already and I will be able to use it?

1. I think the DreamBlaster S2 is the cheapest one that you can get as a new waveblaster board:
https://www.serdashop.com/waveblaster
It sounds better than an AWE32.
2. The AWE32 does not support MPU-401 directly. You have to use AWEUTIL /EM to get Midi support. Even AWEUTIL /EM only supports real-mode games/Midi software. You need non-official utilities like DOS32AWE to get support for protected mode software .
DOS32AWE - DOS/4G compatible DOS Extender with Sound Blaster AWEUTIL MIDI synthesizer support for Protected mode,VIASB
In this respect the AWE32 works better with DOS based Midi programs under Windows 9x (no extra utils required to get MPU-401 support).