MIDI files trigger sounds played on a synthesizer.

Playing MIDI files

play midi example (help·info) from Twelve bar blues

There can be remarkable differences in the sound produced by a MIDI file, depending on the machine on which it is played. MIDI files traditionally only contain instructions that trigger sounds played by a synthesizer. On a personal computer these are commonly sampled sounds contained in a computer's sound card.

The following problems might occur when playing MIDI files:

• The machine on which you play the file must have both the software and hardware required to play MIDI files. You can begin by ensuring that you can play Ogg Vorbis audio files. Digital audio players might play MP3 and most other standard audio formats but most likely will not play MIDI files.
• Your web browser might need a plug-in to play MIDI files by clicking on an embedded link in a web page. Firefox plugin-ins that support MIDI playback include Quicktime (Firefox video or audio does not play) as well as Totem. Safari appears to use Quicktime or a Quicktime plugin. Internet Explorer supports MIDI playback by launching Windows Media Player, which plays MIDI natively.
• Your sound card mixer playback settings might need to be changed. You can enable and unmute all playback devices, and then increase the volume of all of them, to ensure that your sound card sends MIDI audio to its output.
• MIDI files encoded with a more recent version of the MIDI standard might not be correctly rendered if your machine doesn't support that version of the standard.
• Some hardware manufacturers produced proprietary extensions to the general MIDI standard not rendered by all MIDI players. Such hardware-specific extensions are to be avoided in MIDI files uploaded to Wikipedia.

Free software is available to display the content of the most current types of MIDI files in sheet music or sequencer format, or both, including Rosegarden and Lilypond.

If your sound card does not support MIDI, TiMidity is able to play these files, or convert them to other sound formats.