Device drivers for internal MIDI synthesizers are required to respond to certain MIDI messages such as note-on and note-off messages. In addition, it is recommended that they respond to MIDI messages such as the main volume controller message. The following table identifies these required and recommended messages for internal synthesizer drivers. Support for all messages not listed in this table is optional.
| Required Messages | Recommended Messages |
| Note-On with Velocity | Damper Pedal (Controller Number 64) | |
| Note-Off | Main Volume (Controller Number 7) | |
| Program Change, | ||
| Pitch Bend, | ||
Note:
It is strongly recommended that internal synthesizers respond to the main volume message. This message is used in standard MIDI files to control the relative volume of each instrument used in the song.