Why turn MIDI into MP3
A MIDI file is a set of note instructions, so it only plays where a synthesizer is available, and it sounds different on every device. Phones, car stereos, messengers and video sites either cannot play MIDI or play it with a poor built-in sound. When you convert MIDI to MP3, the music is rendered once with a General MIDI soundfont and saved as audio. Everyone then hears the same thing.
Typical uses: sharing a song you composed in notation software, making a backing track for practice or karaoke, putting old game or website MIDI music on your phone, or sending a choir part to singers who need to listen while learning.
What stays and what changes
| From the MIDI file | From the soundfont |
|---|---|
| Notes, timing and tempo | The tone of each instrument |
| Instrument choice per channel | The drum kit sound |
| Volume, panning, sustain pedal | How realistic it sounds |
Use the preview to check the result before exporting. If an instrument sounds wrong, the file may use a GS or XG sound that does not exist in General MIDI, and the closest instrument is used instead.
Choosing a bitrate
Rendered audio is clean and full-range, with bright cymbals and long reverb tails, so MP3 needs a reasonable bitrate to do it justice:
- 192 kbps – good quality, about 1.4 MB per minute.
- 256–320 kbps – the cleanest MP3, 1.9–2.4 MB per minute.
- 128 kbps – acceptable for simple piano pieces or speech-like material.
A three-minute song that is 30 KB as MIDI becomes about 4–7 MB as MP3.
After rendering
If you want a different key or tempo, it is best to change it in the MIDI file with your music software before rendering, because the notes are still editable there. For the audio, Pitch Shifter and Change Speed also work. To make the track louder or more even, use Normalize. And if you have the opposite problem, a recording you want as MIDI notes, try MP3 to MIDI.