USED QSC SPA4 60 4 Channel 60 Watt Audio Power Amplifier cablewall more natural soundstage• 30mm XXL more natural soundstage• 30mm XXL transducers detailed sound reproduction with clear mids and balanced frequency response for studio work• Self adjusting headband automatically conforms to the user's head for a comfortable fit during long sessions• Over ear circumaural ear cups comfortable design helps reduce listening fatigue during recording Scaled to fit 4 4 size cello with a playing length of 27 1 2 inches (700mm) Pulled from a restaurant install after only a year while the bridge mode provides 100W continuous into 4 or 8 ohms and 125W into 70 100V