|Jerry Willard Photo|
Here are two of Jerry's recordings with his Panormo.
Intonation problems are not unusual for nineteenth century guitars as many builders did not adjust the design of their bridge to compensate for the intonation problem that arises because of the physical difference in each of the guitar's six strings. Generally, the stopping point of each string has to be positioned on the bridge so that the string length becomes progressively longer from treble to bass by a total of one or two millimeters. Otherwise, the guitar will not play in tune. Panormo built a raised edge, a raised wood saddle, on the front of this bridge to provide a clear stopping point for each string but no attempt was made to "compensate" for the characteristics of string physics. This fact would account for a portion of the tuning problems but not for all of the false notes.
Next, I turned my attention to the relationship between the length of the strings and the fretboard. I measured the the distance from the nut to the twelfth fret and compared this measurement with the distance from the nut to the bridge.
For a guitar play to pay in tune the latter measurement must be twice the distance from the nut to the twelfth fret plus one or two millimeters. It wasn't. In fact, the distance from the nut to the bridge was less than twice the twelfth fret distance. I was astonished. Legendary guitar makers don't make this type of error. This guitar could never play in tune.
I wasn't happy with this discovery. The guitar appears to be in nearly original condition and I believe it is important to preserve original work. But there were fundamental problems with both the bridge and the fretboard that prevented the guitar from being used in professional concerts and recordings.
There was enough wood in the peaked front edge of the bridge so I knew I could treat it like a classical guitar saddle and reshape it to a contour that would accurately compensate for intonation. As you can see in the photo, the side of the front edge of the bridge has previously been altered as a glue joint is visible where the peaked front piece joins the curved contour where the bridge pins are placed. Either the piece had broken off and been re-glued or some other remedial work had been done to it.
But re-shaping the front of the bridge would only be useful if the fretboard were substantially altered. Since there were so many problems with fret placement I decided there was no other alternative than to replace it. The fretboard was 6.5mm thick at the nut tapering to 4.5mm at the sound hole and had been re-fretted with modern, medium size T frets. My plan was to plane the it down to a minimum thickness and then use a warm iron to loosen the glue and remove the remainder of the board without damaging the neck material or its finish. As I worked down through the board I could see that it had most likely been slotted for bar frets because the slots were shimmed with ebony slivers, as you can see in the photo. Original bar frets are about 0.8mm wide and that is what the slots measured when the shims were removed.
Before I completely removed the fretboard I strung and tuned the guitar. I did this in order to acoustically determine the position of the twelfth fret. Using this information I calculated all of the fret positions.
In order to complete the alterations to the guitar I reshaped the front of the bridge in a way that compensated for the physical characteristic of each string as I discussed earlier in this post. In the photo I highlighted the crown of the saddle with chalk to display its contour. The first and second strings are closest to the front while the third abruptly needs to be longer. The fourth and particularly the fifth move back toward the front while the sixth is about in the middle of the range.
Jerry told me he intends to spend the summer preparing and recording with his Panormo. I'll look forward to hearing the results.