[sdiy] req : midi guitar info

[harry]

Hi Scott (et al)

I have had the same results as Scott. The octave switch of the two low
strings is a really good (if not original) solution. Several commercial
units did the same...  there was a "high strung" version of the Photon
Midi Interface... and a Yamaha "guitar controller" that used all high
E strings tuned to unison.

Scott's solution is probably the most practical and closest to a "real
guitar".

I used to use the Roland GM-70 system... you could count on about a 30ms
delay. I used a digital delay on the guitar output to "time align" the synth
and
guitar attack. This works... but you cannot listen to yourself without
confusion...
and the drummer would watch me for the beat (a good idea.. he's eliminating
another delay as my sound reaches his ears..) but my actions were 30ms in front

of the sound... and he KNEW it....

I've just finished (and I use the term as Eduardo "elmacacoX" does... finished
until tomorrow when I modify it again ;^)  a hex guitar project. I use direct
waveshaping on the guitar strings themselves... then process with VCF, VCA
etc. Its a fully polyphonic approach that has the advantage of no delay. Of
course
it cannot sustain forever... but it does for a long time....

Trying to approximate the pitch for the first quarter cycle is probably not too
reliable..
the attack transient of the guitar is going to spoil that.  You might be able
to play
a quarter cycle of any midi note (within an octave  ;^)  for a short time
before your
brain can process it. Sounds with slow attack will mask the uncertainty anyway.

The Axon measures the time it takes for the pick transient to reflect off the
fret position... this can be faster as its really not measuring the
vibration... but the speed
of sound in steel. It is said to be pick sensitive as well.

I use the method of the "Gold" patent (New England Digital - Synthclavier) for
pitch
extraction... I saw the ads featuring Pat Metheny with the system. If its good
enough for Pat its good enough for me. Two caveats...

1)  My techinque (while good - teehee) is NOT in a class with Mr. Metheny...

~and~

2) I've been informed that while he posed for pictures as a Synthclavier
endorsee...
that his solos were actually recorded with the GR-30 (an all analog system
which uses the guitar strings as a sync source as well... minimizing delay and
error)

Midi guitar is still the Holy Grail as far as I'm concerned...

(now Midi Theremin... that we can do  ;^)

H^) harry

Scott Gravenhorst wrote:

> I'd be interested in the comments of others...
>
> The system I use does not produce analogue outs...  It's
> a MIDI guitar system.  (and the question was about MIDI
> guitar)
>
> First, a whole lot of this has to do with how you play
> it.  I've heard other people do stuff with my equipment
> that I can't seem to do.  So I won't claim to be a good
> guitar player or a good MIDI guitar player.  My problem
> is having a ham fist, heavy hand.
>
> What I can relate is what I've read about the system I
> use and some things I've done to optimize it for me.
>
> First the system I use is a GR-50 synth with a GK-2 pickup
> system.
>
> It is designed to approximate the pitch of a picked string
> by measuring dv/dt for the first quarter cycle.  The GR50
> synth will then start the attack portion of the sound with
> that rough pitch measurment.  As time goes by, more precise
> measurment is made by cycle counting and the rest of the
> sound time is pitch corrected.  The MIDI messages associated
> with this are a burst of MIDI pitch wheel messages (if MIDI
> is enabled).  I wrote some software to analyse this data and
> found that picking strategy is important.
>
> I have never found using this instrument very useful for
> recording MIDI messages.  There's just too much dirt.  For
> me and my ham fisted wanker technique though, it is useful
> (for me) to do pad chords.
>
> As far as optmimizing it, I did this: (and I got the idea
> from a guy's posting on some newsgroup)
>
> I replaced the lowest 2 strings with ones that are 1/2 the
> diameter (hence tuned up an octave).  This speeds up the
> (ordinarily) late response of those strings, although it does
> require that you change the pitch programming of the sounds you
> use to compensate for the octave shift.  I also discovered that
> this almost "nashville" tuning is something I like...  But that's
> something else.
>
> Make the string height to pickup adjustments as close as
> you can.
>
> I hope that wasn't too off topic....
>
> "criss m" <moog at sick.cl> wrote:
> >This is a multi-part message in MIME format.
> >
> >------=_NextPart_000_0042_01C1C207.BA862E40
> >Content-Type: text/plain;
> >       charset="iso-8859-1"
> >Content-Transfer-Encoding: quoted-printable
> >
> >hi guys=20
> >
> >im back after some nice vacation :) and i was wondering if somene can =
> >provide me some links or info about midi guitars (i dont know much about =
> >it)=20
> >but=20
> >i dont know if there are units that translate a analogic signal from the =
> >guitar (electric) and translate into midi mensages??????
> >
> >or if there other sort of midi gitars with switchs or sensors in the =
> >bridge?
> >
> >i just build a  midi keyboard and noticed that ima keyboard fool.... its =
> >hard for me , i think i'll buy piano for dummies....
> >
> >please help
>
> =========================================================
> - Government: The other religion.
> - The media's credibility should always be questioned.
> - Lambs who lie down with lions are lunch.
>
> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
> -- Linux Rex         | RedWebMail by RedStarWare
> -- FatMan: home1.GTE.NET/res0658s/FatMan/index.html
> -- NonFatMan: home1.GTE.NET/res0658s/electronics/index.html

--
Jihad Terrorism Conspiracy New World Order
Revolution Black Helicopters Freedom of
Speech First Amendment Rights: Carnivore Bait
go ahead and READ my e-mail I have nothing to
hide... how about YOU ???