Peterson Electro-Musical Products Inc. peterson, electromusical products, orgaplex, solid state, organbuilding, organbuilders, organ builder, organ building, organ technology, pipe organ, pipeorgans, msp-1000, combination action, relay, magnet, midi, piston, crescendo, expression, stop, key, display, pedal, tutti, master, church music, organs, pipes, microcontroller, microprocessor, stop list, music Peterson Electro-Musical Products, Inc.