19 April 2014

Assembly Complete & An Intro To Sound Ports

The current guitars were both assembled and bound in the past couple of weeks. The cedar / rosewood instrument has a sound port, here are a few words about that.

Some shots of the assembly process:

Necks ready for assembly The maple back ready for assembly Gluing on the sound port reinforcement
Magnets being glued into the
reinforcement piece inside the guitar
Neck glued to soundboard, sides
attached to the heel with wedges,
and glued to the soundboard with tentellones
The cedar guitar having its
back glued on

Unfortunately, I didn't have a camera handy for the binding and elevated fingerboard gluing stages.

Lacote guitar showing Aguado's
 invention. Photo from:
Lyra guitar ca. 1790. Photo from:
A sound port is a secondary soundhole, or holes, somewhere on a guitar. The primary reasons for a sound port are to improve the sound that the player hears (really helpful in noisy or acoustically dead spaces), and to increase volume and dynamic range by lowering the impedance of the air inside the body (but this effect is pretty subtle at best). Sound ports have become rather popular on classical guitars since the 1990's; however, as with many seemingly new ideas, the concept of sound ports has been around for much longer. One of Aguado's numerous creative contributions to the guitar was the idea of putting a second soundhole in the back of a guitar, and Lacote, in the 1820's, was the first to build a guitar with the feature. But guitar-like instruments with holes in the back existed earlier than that.

This is the first of my own instruments to receive a sound port. It is located in the side of the upper bout facing the player, and will have a movable cover held on by magnets, so the size of the opening will be adjustable. You can see the magnets in the picture above being epoxied in place. On one hand, I wanted to be a little conservative about the size of the hole, but at the same time, I wanted the hole to be large enough that there was a point to having a movable cover. Now that this guitar is assembled, it's interesting what the sound port does to the resonances of the instrument.