Posted on August 23, 2019May 23, 2025 by Dale Phillips Intonation in the Real World Intonation in the Real World by Mike Doolin from his 2006 GAL Convention lecture previously published in American Lutherie #92, 2007 Getting guitars to play in tune has been a major topic of interest for many years, both for guitar players and guitar makers, and it has been a major source of frustration as well. During our current “Golden Age of Lutherie” the bar has been raised for standards of craft, playability, and tonal quality, as players have become more sophisticated in their expectations and builders have become better educated and more demanding of their own work. Expectations for accurate intonation have come along with all that: it’s no longer acceptable for a guitar to only play in tune for the first five frets, or in a few keys. Modern players are using the whole neck, exploring extended harmonies, and playing in ensembles with other instruments. They are looking for instruments that play in tune with themselves and with the rest of the musical world. It turns out that guitar intonation is a huge can of worms, because it is really two topics: ▶ What does it mean to be “in tune?” ▶ How do I make a guitar do that? 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 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.
