GR-20 Hexaphonic 19-ET Guitar Improvisation

The Sonar project after recording the improvisation

The Sonar project after recording the improvisation

This study entailed learning how to simultaneously play six instances of z3ta+ in 19-ET tuning with my Fender Mustang using a Roland GR-20 as the guitar to midi interface.

I improvised in an ambient-ish style and explored the fret board combinations both in both harmonic and timbrel relationships with some melodic considerations.

The GR-20 has a mode in which each string of the guitar is assigned a midi channel, channels 1 through 6. Thus hexaphonic output is possible. In this case each string’s output is sent out the GR-20 through a midi to usb adaptor into my laptop and then into Sonar 8.5. In Sonar I assign each string an instance of z3ta+ – a software synthesizer that comes with Sonar that is microtonal capable. Each of the six instances of z3ta+ have a unique preset voice assigned and has a 19-ET tuning file loaded. In the case of the high E string, channel 1, which sounded too high for me, is transposed at Sonar by -19 midi notes which yields the octave below the one I’m playing when using 19-ET.

One of the points of doing this is to make each string spatially different – in stereo-space the strings are arranged 5 3 1 2 4 6 in increments of 20%, i.e., 20, 40, 60 percent off center each side. No hard panning allows some of the stereophonic aspects of the zeta+ voices to be heard.

Here is the improvisation – about 11 minutes and 30 to 40 megabytes depending which high quality format you choose. No post processing was done except to cut off the sacrificial midi note at the end and a slight normalization of the volume applied equally to each channel.

MP3 version

OGG version

Someone asked to see me play this set up – you’ll see it is not a challenge to play.

Here is the equipment used (excepting the amplifier):


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5 Responses to “GR-20 Hexaphonic 19-ET Guitar Improvisation”

  1. Charles Lucy says:

    I tried this back in the mid 80’s using a Shadow pitch tracker and running it into a Yamaha DX7 Mk II which was microtuned.

    As I suspect you found, the latency was so slow that although it would trigger approximately the “right” microtunings, the playing techniques became very limited. Hence as you show, slow passages are more appropriate.

  2. admin says:

    Hi Charles, thanks for the listen and comment. I tried something like that back in 87 or 88 as well – the GR-20 is much much better – the reason I play so slow is from the synthesizer patches – very long attacks for most of them. I believe I hit a few notes with shorter attacks on the low strings at a few points in the improvisation. Though youtube made the video slightly out of sync there is no latency worth mentioning.

  3. […] performance at the Oddmusic Convergence used the same tuning (19 ET), equipment and software as GR-20 Hexaphonic 19-ET Guitar Improvisation with the exception that Session Drummer 3 was added. I performed two pieces that night and this one […]

  4. Nakesha Vandercook says:

    Awesome site, I will be adding your feed to my google reader.

  5. charles lucy says:

    […] upstate … Lucy and Sarah are also preparing for a once-in-a-lifetime trip to Italy, where his …GR-20 Hexaphonic 19-ET Guitar Improvisation Chris VaisvilHi Charles, thanks for the listen and comment. I tried something like that back in 87 or 88 as well […]

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