A stringed musical instrument has a body coupled to a single neck, multiple registers of strings, and a bridge that provides for at least one of acoustic and electronic separation of the multiple registers. The strings are preferrably arranged in paired courses, each of which has two members tuned to vibrate sympathetically with one another. In at least one of the members of each pair is a metallic string, and the other is a nylon or other non-metallic string. Preferred examples include a guitar, and more preferably an acoustic 12-string guitar. The bridge preferably has interleaved saddles for the various strings, each of which has its own associated pickup. The sounding board is reinforced with transverse brace struts. Optional equipment includes a balancing circuit that can be used to balance outputs of the vibration sensors.