Posted on June 30, 2024May 14, 2025 by Dale Phillips The “Corker” Guitar: A Sideport Experiment The “Corker” Guitar: A Sideport Experiment by Alan Carruth Originally published in American Lutherie #94, 2008 Over the past few years there has been something of a trend for cutting holes of various sizes and shapes in the sides of guitars. (Editor’s note: See AL#91 pp. 6–13 for more on soundports.) While a hole in the side of the guitar might or might not directly affect the way the top and back (the main sound-producing surfaces on most guitars) vibrate, it could certainly be expected to affect the vibrations of the air inside the box. I became interested in this when a customer asked if I could build a guitar with a port. Since I’m the sort of guy who likes to have a map when I’m going into new territory, I looked up what information I could find. There was a certain amount on air resonant modes, but not much treating ports, so I decided to do an experiment. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 3 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on July 31, 2019May 23, 2025 by S Mc Herr Helmholtz’ Tube Herr Helmholtz’ Tube by Mike Doolin previously published in American Lutherie #91, 2007 See also, “There’s a Hole in the Bucket” by Cyndy Burton “Sideways” by John Monteleone “Three Holes are Better than One” by Robert Ruck Design innovator Mike Doolin tried an interesting experiment. Mike’s guitars have the distinctive double-cutaway feature and they don’t lend themselves to a port up in the neck/cutaway region for reasons of underlying structure. So Mike put one in the lower bout and very unexpectedly found his Helmholtz resonance had raised something like a major third. He felt that compromised the responses of the guitar. His solution was to “tube it.” The side was ported before I assembled the guitar. After gluing the back on, I realized the change in the Helmholtz when I tapped on the guitar with the port open. It seemed obvious that a shift of a major third up was going to radically change the sound of the guitar, probably killing most of the bass response. I knew that ports in bass reflex speakers are often tubes, where the longer the tube the lower the resonant frequency. I also knew that the tube could be either inside or outside the box. So I initially held a roll of toilet paper against the port, letting the cardboard core of the roll form a tube that extended the port. That dropped the main air resonance back down, showing me that I was on the right track. Then I turned a tube of wood on my lathe to fit the hole and experimented with the length until the air resonance moved less than a half-step with the port closed or open. I recall the port being 1 1/4" in diameter and the tube being about 2 1/4" long, but that’s just from memory. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on January 1, 2010May 14, 2025 by Dale Phillips Three Holes are Better than One Three Holes are Better than One by Robert Ruck previously published in American Lutherie #91, 2007 See also, “There’s a Hole in the Bucket” by Cyndy Burton “Sideways” by John Monteleone “Herr Helmholtz’ Tube” by Mike Doolin Classical guitar maker Robert Ruck pioneered sideports for nylon string gutiars. He describes how the idea materialized out of several experiences going back to the begining of his career in the ’60s. A strong advocate, he now offers ports as an option on all of his guitars. Since late 1999, I have regularly used sideports in my guitars. My experience with the resulting 150 or so ported classical and flamenco guitars with various designs is consistent, predictable, and all positive. There is an increase in loudness both for the player and for listeners. In listening tests with several fine players, we have concluded that the guitar is louder for the audience, too. The fundamental tone quality of the guitar stays the same, but it is louder, has stronger trebles, and has a more balanced quality for the player, opening up an area of sound around the player that is not normally heard. Since we as players sit somewhat asymmetrically to the guitar and the conventional soundhole is positioned to our right, there is an area on the left side of our heads that does not receive as much sound as the right side. We grow up hearing the guitar this way, so we never question it. Players comment that it’s as if one is hearing the guitar in stereo for the first time. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on January 1, 2010May 14, 2025 by Dale Phillips Sideways Sideways by John Monteleone previously published in American Lutherie #91, 2007 See also, “There’s a Hole in the Bucket” by Cyndy Burton “Herr Helmholtz’ Tube” by Mike Doolin “Three Holes are Better than One” by Robert Ruck Archtop builder John Monteleone is famous for his avant-garde approach to these instruments. He explains how sideports came into his mix. The concept of incorporating the use of alternative soundholes in the side of my guitars came to me at an early age when I had built my first acoustic guitar, back around 1963. I would place my ear on the side of the guitar and wonder how I could make the guitar sound just like that. I figured that the only thing preventing me was the side of the guitar itself. Even then I knew that you couldn’t just cut out a hole into the side of the instrument without inviting structural failure. There had to be some kind of reinforcement to permit it to happen. How could I make this happen on my guitar? Some years went by before I actually got to revisit this idea and to address the best and most precise method of execution. While still in my old workshop in the 1980s I had done several drawings for this system of side soundhole placement but never got to build it. Then in 1995 Scott Chinery put the challenge to me to come up with a way to hear the projection of the guitar in a better and more effective way for my contribution to his Blue Guitar Collection. Scott, unbeknownst to me and the other blue guitar makers, had also challenged a couple of the other luthiers during this time by planting this seed with them as well. It seemed to me the perfect invitation, if not an excuse, to explore this avenue of tonal possibility. Experimentation of design is historically not novel to the idea of trying to make improvements to nearly all musical instruments. A visit to the US Patent and Trademark Office will provide a staggering volume of inventions for fretted instruments alone. Many ideas never made it to fruition. But it is wonderful to see the many recognizable ones that did. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
