Roland V-Guitar (was Harry's rant)

[Don Tillman]

   Don wrote:
   I *think* the Roland V-Guitar system is simply a standard DSP-based
   effects unit, including pitch shifting and distortion, plus a digital
   filter to emulate body resonances and a hex digital filter to emulate
   the response of various pickup types and positions.
    
   (The frequency response due to the pickup position and width is with
   respect to the wavelength on the string, so it has to be done
   seperately on each string.  Hence the hex pickup.)

I believe I've found the main patents for the Roland V-Guitar:

US 5,367,120 Musical tone signal forming device for a stringed
             musical instrument, Atsushi Hoshiai, Roland Corporation 

and:

US 5,731,533 Musical tone signal forming apparatus for use in
             simulating a tone of string instrument, Atsushi Hoshiai,
             Roland Corporation  

A comb filter simulates the nodes you get from a pickup at a
given position from the bridge.

(You know how the fourth harmonic on an open string is inaudible with
the neck pickup of a Stratocaster?  The node is right over the
pickup.)

Also another comb filter undoes the filtering effect of the hex
pickup's position.  And another comb filter contributes the effect of
pickup width.  The second patent is a way of dealing with the effects
of simulating multiple pickups.

  -- Don 

-- 
Don Tillman
Palo Alto, California, USA
don at till.com
http://www.till.com