PDA

View Full Version : X-ray



Hluth
01-04-2016, 06:05 AM
I started making bevel edge tops a few months back with what I call “inside out” purfling. After building about 5 of them, I’m beginning to suspect that it noticeably improves the overall quality of the sound. This isn’t a new idea, Taylor Guitars thought enough of it to patent a version where a half-oval channel is routed all around the underside of a standard sound board next to where it joins the lining (kerfing). The picture shows a just completed ukulele using the bevel edge in a red spruce top. Red spruce is very translucent and my 7w inspection light is enough to show an x-ray-like image of the top. You can see where the beveled edge tapers from about .075: to just under .050” where it meets the lining. The other picture shows the top bevel profile and purfling.

87045 87046

Beau Hannam Ukuleles
01-04-2016, 06:09 AM
This is a centuries old method of improving the tone and projection of any instrument.

Red Cliff
01-04-2016, 10:47 AM
So, just a quick question, what happens to all the end-grain that is now exposed around the edges and not covered by bindings?

Recstar24
01-04-2016, 11:00 AM
I don't deny that it may be a sonic improvement, but could someone clarify why exactly it improves sound from a scientistic, acoustic perspective?

Beau Hannam Ukuleles
01-04-2016, 01:39 PM
I don't deny that it may be a sonic improvement, but could someone clarify why exactly it improves sound from a scientistic, acoustic perspective?

Thinning the edge helps the top pump- like a speaker cone.

Recstar24
01-04-2016, 02:52 PM
Thinning the edge helps the top pump- like a speaker cone.

As a self proclaimed audiophile whose former hobby was into elaborate speaker systems and experimenting with different speaker drivers and cones, I completely understand why that makes sense ;)

stevepetergal
01-04-2016, 03:15 PM
The Seiler Piano company of Germany started routing a channel all the way around their soundboards, not quite at the edge, in the 1980's. The sound improvement was startling. Must be the same principle.
I only wonder if this will diminish the lifespan of the soundboard.

granger
01-05-2016, 02:01 AM
Hluth,

Your continuous innovation is inspiring. I am finishing a short scale, 20.125" tenor guitar and am using the Taylor half oval channel routed into the sound board. Depth is 15% of top thickness. Can't wait to see how it sounds.

jcalkin
01-10-2016, 04:33 AM
87229 8722787225 87228 87226

I started routing the same sort of bevel back in the 1980s to expose the solid walnut lining I used on my True Companion travel guitars. It also breaks the hard corner of the instrument, making it a lot more comfortable to play. I did the same thing to my 2x4 uke (pix to come soon) for a different reason. I'm going to paint the ribs of the uke, with the paint extending onto the bevel to act as a dark frame to the plates.

The effect doesn't show up so well on the pic of my travelers, but the kabosy, mando family, and casket guitar show it OK. I'm happy to see other people trying the technique.