The list of Acoustic Matrix users reads like a who's who of acoustic musicians. The secret of this undersaddle pickup's sound (and popularity lies in its proprietary co-polymer pickup and active endpin-mounted preamp. Smaller sized concert/auditorium instruments and nylon string classical guitars will benefit from the slight bass boost in the Natural I preamp. This version of the Acoustic Matrix can also work well in some larger guitars, especially at low to medium stage volumes.