Saturday, November 8, 2014

Playing Light with a Guitar

The purpose of the article is not to be gratuitously technical but a measure of technical information is required to explain it.  The overall theme is how to make light with your guitar.

The Godin xtSA is one of a number of guitars with MIDI access in that there is the capability in the instrument to generate MIDI data and transmit it via cable just as it does the analog signal via a 1/4" cable.

MIDI is the digital language equivalent of the notes you play and this information is typically sent to a Roland GR-20 guitar synthesizer or any variation that supports input from a 13-pin non-standard MIDI cable.  That additional pin is for power as standard MIDI does not supply power.  The 'power pin' means the guitar does not have to carry an onboard power supply for the MIDI pickup and thus there is nothing to break and no batteries to replace.  Other devices such as MIDI tablets use standard MIDI cables and thus onboard MIDI tablets require a battery which is always a nuisance.

The drawback to Roland 13-pin MIDI cables is that they're expensive and they're crap.  However, they will work for a while.  There are other types of cables (e.g. Planet Waves) but that's a pseudo-company as Planet Waves stopped making them some while ago.  The Planet Waves 13-pin cables are less than half the price but Roland GKC cables but they are of even worse quality than the ones Roland makes and they're commonly-available on eBay.  I am almost dead broke but I spent $50 on a Roland cable rather than spend around $25 on a fake one from Planet Waves as no-one is rich enough to waste money on poor quality.

The capability to create MIDI means the guitar can drive a synthesizer and I've written previously on how beautiful this sounds but it goes beyond that.  The light / laser understands MIDI and thus lights can changed based on the note played on the guitar.

The immediate question to me is what should the change be.  For example, you play Do-Re-Mi on the guitar and each note will produce a change in the lights even though the notes are as close together as can be.  The controller will listen to notes 0-127 so note 0 should be quite a bit different from note 127.  However, playing notes 0,2,3 as the start of a scale as above, should not change the lights so radically.

This will be conceptual until I get the cable but what is known right now is that it is definitely possible, even if a huge hassle, to program 0-127 patches on the light controller.  It's known it responds to notes 0-127.  The in-practice part comes on Monday or Tuesday when I get the cable.

For cabling, the Roland 13-pin MIDI cable goes from the guitar to the Roland GR-20 guitar synth.  MIDI THRU from the GR-20 goes to a Korg synthesizer.  MIDI THRU from the Korg goes to the light / laser controller.  This is called 'daisy-chaining' and it permits all four devices to see the information at very close to the same time.  It will likely appear simultaneous but, in a computer context, it is not identical.

Fifty bucks for the cable hurts but I only have to make it three and a half days.  I did eat a can of Progresso Chicken Noodle Soup and that's my ever-trusted standard as that was the only stuff I could eat when I got so sick a few years back.  There's damn sure wholesome goodness in that stuff and it's cheap.

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