Voicing the GH1

[BDeTar@aol.com]

Dave Porritt, an excellent tech at SMU in Dallas, sent me an email regarding
voicing procedures for a GH1 and I thought there might be 1 or 2 others that
would benefit from this, so here's the response I sent him:

Now, let's see if we can make your life a bit easier as to the tuning and
voicing of your GH1.

First, make sure that the strings are seated at the bridge as well as level
at the "V" bar and agraffes.  To do the leveling at the "V" bar and agraffes,
use a 1/4" brass rod tapered and notched at one end to fit on one string at a
time.  Jim Coleman Jr. has a great tool he sels for this.  I modified mine by
bending it to form a nice handle.  Remove the action and use the tool to
"lift" the strings at the "V" bar and agraffe.

Next, check the density of the hammers with your voicing tool.  Use a
weighted voicing tool fitted with three #8 or #9 needles.  #6 needles are too
big for Yamaha hammers.
Support the hammers with a voicing block before doing any actual needleing.

Use enough force to drive the tool into the hammer so that the tip of the
tool impacts on the hammer head.  This distributes the effect of the needles
a bit farther in the hammer.  What you're looking for is to have the hammers
feel firm but not hard.

HERE'S THE SECRET: The one exception is at the tenor break.  Here, the
tension goes from about 165 lbs. to about 104 lbs. over about 6 notes. That's
a pretty dramatic drop in tension.  If you have Quattro Pro (or Excel) I can
send you a graph of this and other aspects of the scale that you may find
interesting.  I won't get into a discussion as to the pros and cons of this
design.  The fact is what it is so let's enjoy the solution instead of
debating the cause.

So, to get around the drop in tension, we need to make these hammers a bit
softer than the rest.  Start at the first hammer in the tenor and double the
number of stitches you gave the rest of the hammers.  In other words, if you
did 4 stitches on the mid-range hammers, do 8 stitches on the first 6 hammers
in the tenor.  Aim fairly high on the shoulders, about 11:00 on the front
(key) side of the hammer, and about 12:30 on the rear (damper side) of the
hammer.  Go slow and test often.  You won't be able to completely eliminate
the tonal change at the bass/tenor break, but you will be able to get it to
the point that it is more than acceptable.

It probably would make more sense to see and hear this in a demonstration,
and, to that end, we've developed a "show and hear" program to be presented
at conventions and PTG meetings.  I'll be doing an all day seminar in which
this wil be part of the program in Albuquerque the first week in May if
you're in the area. If not, I'm sure you'll get a chance to see it somewhere
soon.


Take care, Dave and I hope this helps.

Brian De Tar                   "NO OBSTACLES...ONLY OPPORTUNITIES!!"
BDeTar@aol.com