Why is tracking sometimes inconsistent when using a MIDI guitar controller, as compared to a MIDI keyboard?
I‘ve heard many players sound absolutely fantastic using MIDI guitar controllers. In most instances they work incredibly well, but the path can sometimes be fraught with complications. Guitar and MIDI synth interface set up is a critical issue for most players, and this is also where most systems that aren’t working well have problems. If one follows the directions on set up in the manual to the letter, and takes care to make sure it stays set up that way, life is much easier. Most systems with inconsistent behavior are not set up correctly.
But even when things are set up perfectly there are still potential problems. MIDI information travels at a rate of 31,250 bits per second. While this data rate is fine for most MIDI functions, it is somewhat slow for the processing of something as complex as all of the subtle nuances that take place very quickly as a guitarist plays (especially where strumming is involved). When a guitar is used as a MIDI controller, all of the information being played on that guitar needs to be converted to MIDI (the pitch of each note sounded, how hard each note was sounded, how long each note sustains, does the note bend, what is the bend range, etc.) and then processed. This is a tremendous amount of information to translate from an analog signal in real time, and along the way many very fine decisions must be made (that muted note that the player sort of half struck, was it supposed to be a note, or was it a mistake in technique?) quickly. The speed of translation can be complicated by the fact that on low notes the processor takes longer to recognize the pitch because the string isn’t vibrating as fast (just basic physics there). The result can be occasional delays and/or glitches in the flow of information, especially if set up is not optimized. Things such as strumming or picking fast single note lines while bending notes (even if the bending is very subtle) can become very disruptive to the information flow. Turning off sensitivity to potentially extraneous information such as pitch bending can produce more consistent operation. Depending upon how hard you press your strings, and at what angle, you are almost always generating pitch bend information while you play. Much of this information is unnecessary and you will find that your synth patches actually sound better if you turn this off. There are a variety of other tips and techniques that can help as well. Some are in the manuals, while others are learned from experience. If anyone out there has anything to add that might help others please feel free to send e-mail to inSync@sweetwater.com.
With all of that said, I have seen many guitarists over the years with properly set up guitars and synth interfaces give consistently good performances. Meanwhile there are many new items on the market such as the Roland GR-30, GI-10, and the Axxon MIDI controller that utilize new innovations in guitar synth technology to improve tracking and playability. Some ability is still required to adapt and play the instrument for what it is though. Similarly, a die hard pianist still has to modify his playing slightly in order to play even the very best 88 note controllers.