A magnetic resonance modulator system for acoustic stringed musical instruments having a plurality of magnets. The resonance modulation is a function of the plurality of weights and locations of placement of magnets on the instrument. The attachment of the resonance modulator to the instrument and its infinite adjustability is achieved by using the attractive magnetic forces of the magnets to hold them in place through a vibrating component of the instrument, in any position on the instrument, making any location adjustment and consequent resonance or tonal adjustment quick and easy.