To pairs of Yamaha NSAW150 speakers were inserted back to back in the left and right side of a large auditorium four speaker sound system which was seriously deficient in full range accustic sound response to main floor and sound attenuated balcony listeners.The quality of resulting audio reinforcement from the NSAW150'is excellent for physical size and frequency response. Quality of construction in product is remarkable. Mounting hardware positioning to walls or ceilings include brass threaded insert bushings with machined brass capture nuts for durable accustical positioning. Voice coil terminal posts are optioned for direct speaker wire attachment or plugged termination.These units are high quality products honestly meeting elements of advertised specification. As a practicing sound engineerinstaller,I recommend the integrity of Yamaha's NSAW150 product for audio delivery in areas of sound performance application.A very quality product for the cost.