Limitations of MIDI

At this point it is necessary to state the obvious: There are a ton of different MIDI devices made by many different manufacturers. Each have different features, different sounds, and, in some cases, add propriety functions to the accepted implementation of the MIDI standard (especially some of the first MIDI-compatible synthesizers). Just because a device has a pitch bend or modulation wheel on its control panel doesn’t always mean that it can receive MIDI information related to that specific controller. The only way to know for sure is to read that unit’s users manual. (You do read the users manual, don’t you?) Don’t worry about any one device “freaking out” just because it receives MIDI data about a controller that it cannot respond to. Any data a MIDI device receives that it doesn’t understand, it simply ignores. (Unlike spouses, which one can never quite tune-out completely.)

Theoretically, MIDI can transmit sixteen unique musical tracks with up to 128 notes in each “performance”. Each note can have its own attack, decay, sustain, release, aftertouch, etc. In addition to this, each channel can send data that covers 64 different control types (breath control, modulation, pitch bend, channel pressure, etc.) That’s alot of data coming and going when you have a bandwidth of only 31,250 bps. All of you web surfers out there probably know by now if you’ve been surfing for any length of time, what it is like to hit an over-tasked web server. When the channel gets clogged, you inevitably wind up with delays… something unacceptable when playing music.

When a key is pressed on your master synth, it takes up to seven milliseconds for the synth to route that MIDI information to its MIDI OUT port. It takes another millisecond for that message to travel to the next instrument, which in turn takes up to seven milliseconds to respond to the incoming message and play the note. This delay is not generally noticeable to the ear, and MIDI can transmit up to 1000 NOTE ON or NOTE OFF messages in a single second. (This does not count the other MIDI messages, like pitch bend, modulation, sustain, etc.) If you are playing live… then you shouldn’t really worry about it. I doubt seriously that you have chops enough to outplay MIDI bandwidth. BUT… if you are in a studio environment with lots of MIDI tracks being recorded into a sequencer, then, it is quite possible that you might reach the limit of the bandwidth if your composition is complicated. If you have a lot of instruments, then a THRU box is something that you will want to invest in, or a MIDI Patch Bay (if you have the cash!) This can help minimize the effect of transmission delay and keep you making music instead of pulling out hair, something which I – fortunately – have an abundance of.


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