Musicality is everything about how a guitar sounds.
The challenge is to articulate what that means in terms of the acoustical properties of the guitar and how these properties relate to the woodwork.
It begins with an understanding of consonance and dissonance; what harmonic content of a string sounds good and which harmonics you can best do without, and then making sure they don’t get in the way of the “good” harmonics. Its about understanding how to get the string’s harmonics not only to play in tune in and of themselves, but to play in tune with other strings. That’s in tune to the equally tempered scale.
Why is this important? Because the more of the right harmonics you have playing in tune across all the strings, the clearer the tone, the better the note separation and the better pitch accuracy you get, which adds up to a guitar that sounds a whole lot better than most others, because precious few guitars play anything like in tune. Single notes are clear and translucent, chords are sweet and articulate.
So what’s different about my guitars? I build them having a very clear understanding of the interaction between the string resonances and the guitar's body resonances; its air resonances and its wood resonances. If you shift the pitch of a body resonance it will react differently than before with the resonating string, shifting the pitch of the string’s fundamental frequency and its harmonics. So if you don’t pitch the body resonances in the right place as part of the design and build process, you have a guitar that never plays properly in tune, which is pretty much where most guitars sit and why mine are different.
But there’s more to it than keeping things consonant; where it gets really hard is achieving consonance (in-tuneness across all the strings) with responsiveness, evenness and volume all at the same time. That, in a nutshell, is what the book is all about.
The picture on the right shows one of my compensated nuts on a classical guitar. Compensating the nut as well as the saddle is another significant contributor to the musicality of a guitar. Until I figured out the physics and engineering of this I hadn’t realised how much better a guitar could sound.