TBX1 Tuning Box

TBX1 Tuning Box

TBX1 close up

TBX-1 Review – Jahloon, March 2008

The TBX1 is a MIDI based microtonal convertor
allowing instant retuning of most MIDI based devices

Purchased: March 2007 direct from H-Pi Instruments $329.99 (March 2008 price $299)

What does it do?

The TBX1 is a MIDI device that takes in pitch information and converts it to another pitch. So with a MIDI keyboard or MIDI guitar you could play the note of C and the TBX1 can convert that C to any other note or micropitch.

Not only that single note though, the whole range of 128 MIDI notes can be converted to any pitch you desire.

This is a huge leap forward for microtonalists, as with the TBX1 you can play in any scale you desire, switch from normal 12tet to a just intonated scale or change to equal tempered 19tet at the push of a button. Now there already is software available to do this on a PC, (Scala etc.) but this is a self contained box, at home with your pedalboard or sat next to your keyboard.

There is also a bypass button which allows MIDI data to pass through the TBX1 unaltered.

The TBX1 comes pre-loaded with 128 tuning tables starting at 5 notes to the octave through to 205 notes, there are some very useful tunings; 17 Turkish Saz, 19 Arabic Farbi, 22 Carnactic Sutri, Partch’s Indian Chromatic, plenty to go at.

There are 16 programmable presets which can be set up to hold your favourite tunings. When selected they can also transmit bank and patch messages to select different instruments on your synth module.

How it works

Quite simple really, it takes an incoming MIDI note, such as note 40 (E3) goes to the tuning table finds the new note, perhaps it is E#, so it sends a pitch bend instruction to play note 40 plus 43 cents to the MIDI output.

Now as that pitch bend instruction can only be sent once on one MIDI channel the TBX1 has to transmit on multiple MIDI channels in order to achieve polyphony. The channels used are selected from 16 push buttons on the front panel. A nice touch is the MIDI channel 10 button is grey (as opposed to black) as most synth modules reserve drums for channel 10, its a reminder it might not be wise to select.

The 128 tuning tables mentioned earlier are each actually composed of 4 layers. Each layer has a tuning table of 128 notes. The layers are accessed using different MIDI input channels;
Layer 1 = MIDI channels 1,5,9,13
Layer 2 = MIDI channels 2,6,10,14
Layer 3 = MIDI channels 3,7,11,15
Layer 4 = MIDI channels 4,8,12,16

This feature is extreemly useful for MIDI guitarists, more in a minute…

If you need to create your own tunings a PC/MAC package is supplied to do just that. In addition it will import Scala file tunings, so you literally have access to every scale tuning ever created.

For the Guitarist

Now on the guitar we only use MIDI notes 40 to 88, but whereas a keyboard is a single continuum of notes, a guitar is six seperate strings, usually needing six MIDI channels.

This is where the four layers of tuning tables are needed. If we create a 19tet tuning on a standard guitar, the octave is on the 19th fret, not the twelvth. Playing MIDI note 67 (G) on the second string produces an E, yet playing MIDI note 67 (G) on the first string needs to produce an F#. So this is where the layers come into their own, the only drawback being that strings 1/5, and 2/6 share a layer. On standard tuned guitars this means notes beyond the 18th fret on the 5th and 6th strings are not valid. You could get round this by tuning the guitar differently, but beyond the 18th on the bottom strings is a place I rarely go.

TBX1 files

Here is the fun part. Each of these files converts your standard MIDI guitar into a 19tet guitar.

Your guitar to MIDI device should be set to chromatic scale, or select a piano if you are using GR20/30/33 type gear. (For fretless players, this is like snapping your frets back on.)

If using GR20/30/33 as the synth module, the patches already have a bend range of 24.

If using other synths you should change the bend range accordingly, it is usually 1.

Note: These files have been updated to the new CSE format. All are set for +/-24 bend range. I’ve also included a zip of all the sample files programmed for guitar synth bend range of +/-24.

Zip of 19TET files

Programmed for guitar synth +/-24 bend range

19-guitarEADGBE.cse – 19tet Normal tuning – E A D G B E
19-guitarEADGCF.cse – 19tet Fourths tuning – E A D G C F
19-guitarEACEGA.cse – 19tet Open minor 7th tuning – E A C E G A
19-guitarEGbdEG.cse – 19tet Accidental tuning – E G Bb Db E G
Zip of CSE example files – programmed for guitar synth +/-24 bend range

More info and chord shapes can be found at: Tunings for 19 Tone Equal Tempered Guitar

Overall Impressions

Well, I did buy this box a year ago, on its initial release. Soon I became the bane of designer, Aaron Andrew Hunt’s, life. All of the guitar based equipment was based around different pitch bend values and there was a stream of e-mails with software updates and enhancements on an almost weekly basis.

Aaron did supply fast response and support, even including providing the bypass button mentioned earlier.

The TBX1 has proved to be a very useful piece of equipment, allowing me to hear scales and compare them rapidly with each other.

It is also a great tool for a fretless player, and opens up the world of microtonality.

Breaking News – Feb 2009

We have heard of an immenent upgrade to the TBX1 firmware:

Modification to the startup sequence requirement, allowing TBX1 to be turned on or off and things connected to it to be turned on or off without requiring the previously annoying reboot startup sequence.

Unit now allows presets to have the BANK message set to OFF, so when a preset button is pressed bank change messages are NOT sent.

Now allows presets to have the PATCH message set to OFF, so when a preset button is pressed patch change messages are NOT sent.

These improvements allow better compatibility with active sensing MIDI gear and software synthesizers.

We can confirm that the new firmware and control software greatly improve the usability of this great piece of kit.



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