The concept of modal tuning is summarised as follows: Guitars radiate sound from their vibrating parts, mainly the top plate. If a guitar top vibrates in a different way, it produces a different sound. The different ways a guitar top vibrates are called modes. If the modes are tuned to resonate at particular frequencies with particular amplitudes, we can shape the way a guitar sounds. Learning how to manipulate the parameters of the modes and, in particular, understanding what the target frequencies should be has been the focus of my research and development efforts over the last 10 years. The fruit of this research is manifest in my range of guitars. Modal tuning is intrinsic to gaining consistent acoustical performance from guitars and is how I achieve consistency in my guitars. Modal tuning is grounded in sound physics and engineering principles, unlike the majority of popular methods that assign “brace tuning” and “tap tuning” to some form of art. Modal vibrations and modal tuning are the fundamentals behind how guitars work, and why different models of guitar sound different; but the subject has a miniscule following. That’s easy to explain - it involves complex physics and mathematics! For those interested, I run a three day course on the subject, which, so far, I’ve delivered to ~80 luthiers in USA and Australia.