The brushless DC (BLDC) motors/gearmotors are the quietest of all of our technologies. They are then followed by the AC motors/gearmotors – specifically the three phase and permanent split capacitor motors first and followed by the split phase motors. The Permanent Magnet DC (PMDC) motors will run the loudest of all three technologies. Bodine values itself on high quality, quiet motors and gearmotors. "Loud" is relevant, and application-specific, but all of our motors and gearmotors, in all three technologies, should run efficiently and quietly.