MIDI-guitar (was: Touch Switches/TS instruments )

Sun May 14 18:15:44 CEST 2000

Since y'all want to play I'll share some experiences...

1) check out the "Guitorgan". sorry I don't know where but i bet
its out there. It was a guitar - organ that worked by cutting the frets
inot 6 pieces... and wiring to all of then.

2) The best "midi controller in the shape if a guitar" goes to Yamaha...
who uses a combination of piezo echo-ranging (fret position) Hex pickup
(amplitude) and Light sensing (for string bend angle) Think it was called G10.
Say one on E-bay not long ago, but missing the control electronics... This did
NOT play as a reguler guitar...

IMHO Its unfair to call instruments that do not make "guitar" sounds (ie tuned strings and
pickups..) Guitar Synthesizers.  So the Yamaha, Casio DG whatever, Synthaxe, and the
Photon (high strung model only) do not qualify. They are hip arternative controllers, which
are easily accessable to one "reasonably skilled in the art of guitar playing:, but they
have given up being a guitar to get around the big GUITAR SYNTH problems.

I've done wired frets before. The problem is this

When you push down a string, the fret makes contact at two places, the fret between the
finger and the bridge (good) and the fret between the finger and the neck (bad). So if you
plat a simple "barre" chord (lets use the E position at the 5th fret = Amaj)

The low E string connects from the 4th to 5th fret.
The     A string                                6th to 7th
The     D string                                6th to 7th
The     G string                                5th to 6th
The     B string                                4th to 5th
The high E                                      4th to 5th

Since both strings and frets are electrically conductive, that means that
all these strings are shorted to each other. If we scan the frets, we see
all strings between the 4th and 7th fret (not good)

So the way around is to cut the frets into 6 pieces. Now scanning works.
The Guitorgan did this, and cut the frets at a 45 degree angle, so a bent
string could slide over the cut. Dicey but would work in theory.

Think what a fret job costs on that puppy. Or what it is like to manufacture...

I made one that "worked" by using non-conductive frets (for a test I used glass
stirring rods, but modern ceramics might work. Anyone know a good, cheap
hard non-conductive metal ?  Then I used a brass "pad" under the string. The string can now
touch only one point, but you have to be a GORILLA to play it, since guitarists
push "just hard enough" to fret the string, not to nail the strings all the way to the
fingerboard.... Of course trying a bend didn't work once you fall off the pads...

The Piezo Echo ranging pings the string at an ultrasonic frequency at the bridge, then gets
the flight time of the echo. Don't work with a bent string, or a wound string... so no good
for a Guitar.

Other people have tried the resistance of the string, constant current, etc.  My take on
a winning circuit would be a reflective sensor in the middle of each fret, looking for
finger
presence. Coupled with the good old P/V conversion after the string pitch has been guessed
by the finger position.

We are not yet at the "millenium" eh ???

H^)  likes this thread

"T.J." wrote:

> Hi Everybody,
>   I don't think it's a Casio DG-20. This unit
> is basically the same as the DG-10 but with
> MIDI out. Has nylon strings, very cool, but
> toy like.
>
> Have a pic of the DG-20 (the one on the bottom left).
> http://www.geocities.com/SunsetStrip/Frontrow/4877/dg20.jpg
>
> Here' a link to the "Synthaxe". No longer in production, but
> wild looking.
> http://www.hollis.co.uk/john/synthaxe.html
>
> And then there's Starr Lab's line of MIDI guitars.
> http://www.catalog.com/starrlab/
>
> And here's a german link of alternative controllers. Including a
> laser harp. Strange controllers here.
> http://privat.schlund.de/o/officeandtown/stoffel/alt_controller/alt_midi_controller.html
>
> Perhaps one of these is the model you were playing?
>
> Terry
>
> Theo wrote:
>
> > Sounds like it, maybe my memory is a little fuzzy.
> > Must have been somthing like 10 years ago.
> > tried one with no stings on the fret board I'am quite sure about that.
> > There was a vibrato handle and it had midi.
> > Remember it fun to play with, even for someone as lousy on the string as me.
> > Almost like a toy seems a bit like a understatement to me...
> >
> > Cheers Theo.
> >
> > ----- Original Message -----
> > From: Peter Snow <psnow at magma.ca>
> > To: Theo <t.hogers at home.nl>
> > Cc: <matti at devo.com>; <synth-diy at node12b53.a2000.nl>
> > Sent: Sunday, May 14, 2000 5:54 AM
> > Subject: Re: MIDI-guitar (was: Touch Switches/TS instruments )
> >
> > > Theo,
> > >
> > > Perhaps you are thinking of the Casio DG-10. It has the nylon strings
> > > that trigger the sounds.  Also has the rubber fingerboard that detects
> > > which note you are fingering. The strings run the whole length of the
> > > neck back to the "bridge", just like a real guitar but they play no part
> > > in the note generation, they just act as triggers. No dynamics either,
> > > i.e. it doesn't matter how hard you hit the string, it plays the note at
> > > the same volume.
> > >
> > > Six note polyphonic, very limited number of preset sounds built-in. Also
> > > has rhythm section and built-in Speaker. It's almost like a toy.
> > >
> > > It is an interesting little beast to play, but takes a bit of getting
> > > used to.  You cannot bend stings or do vibrato, though it can do
> > > hammer-ons and pull-offs quite nicely. Only sound I found useful was the
> > > jazz organ.  And no CV or trigger out, so no interfacing with other
> > > synths, at least until you modify it!!
> > >
> > > I believe the Casio DG-20 is the MIDI model. I have never seen one so
> > > maybe that is the one with the "ribs" instead of strings?
> > >
> > > Cheers,
> > >
> > > Peter
> > >
> > > Theo wrote:
> > > >
> > > > Lasers? Good havens you sure like it the hard way.
> > > > Chances are that the lasers will play like shit, because you won't be
> > able
> > > > to feel them.
> > > > What about short strings;
> > > > 1) simple approach, non velo: connect short string to a micro switch,
> > > > 2) elegant approach, velo sens: measrue the string movement and
> > translate
> > > > that into a triger pulse.
> > > > The srting may be stif pices of metal, like on the Digitar.
> > > >
> > > > If you only want CV control the whole thing could analog, no midi
> > needed.
> > > >
> > > > When midi output is no problem you may want to check out the Casio midi
> > > > guitar (the japanece Casio from the wimpy keyboards).
> > > > Not sure if they still make them.
> > > > It has a rubber fret board with no strings and rubber ribs as string
> > > > triggers, althoug I saw a model that used 5inch "real" strings as
> > triggers
> > > > once.
> > > >
> > > > Cheers Theo
> > > >
> > > > ----- Original Message -----
> > > > From: <matti at devo.com>
> > > > To: <synth-diy at node12b53.a2000.nl>
> > > > Sent: Sunday, May 14, 2000 1:00 AM
> > > > Subject: MIDI-guitar (was: Touch Switches/TS instruments )
> > > >
> > > > > Okay, this is even more off the topic, but casio's post brought
> > something
> > > > up:
> > > > > have you ever considered using a MIDI-guitar (not sure of the real
> > name)?
> > > > It's
> > > > > (those that I've seen, anyway) as follows: laser beams are emitted
> > from
> > > > the
> > > > > bridge, and picked up just before the neckboard; if one of the beams
> > is
> > > > blocked,
> > > > > an output is sent via MIDI, indicating that a note has been hit. Note
> > > > control is
> > > > > done via four sets of keys replacing the frets on the neckboard. Now,
> > > > assuming
> > > > > that you've equipped your modular with a MIDI->CV (or are using a
> > modular
> > > > > emulator on your computer), this has a certain amount of potential.
> > > > >
> > > > > ONly problem here, is that they are moderately expensive. Which brings
> > me
> > > > to a
> > > > > more relevant point -------> does anybody know of any schematics for
> > such
> > > > a
> > > > > device? I've looked myself, and not found any (the lasers may be a
> > > > problem.....)
> > > > >
> > > > >