AD-C4T The ceiling mount 2-way co-axial system shall incorporate a 4.5-inch woofer with treated-paper cone and a 19 mm aluminum dome tweeter. The tweeter shall be mounted coaxially in front of the woofer on a waveguide that matches the directivity of the two drivers at the crossover point. The system shall meet the following performance criteria: conical coverage angle of 150 degrees; frequency response of 70 Hz to 20 kHz +0/-10 dB, measured on axis; sensitivity of 87.5 dB SPL in half space at 1 meter with an input of 4 V rms; maximum continuous output of 102 dB SPL; maximum peak output of 108 dB SPL on axis at 1 meter; power handling of 30 watts for 8 hours with an IEC noise signal; recommended amplifier power of 60 watts; nominal impedance of 16 ohms. The loudspeaker shall have a switchable low-distortion, wide-bandwidth laminated core transformer with taps for 30, 15, 7.5 and 3.8 watts at 70V and 30, 15 and 7.5 watts at 100V. The system shall be switchable between 16Ω (bypass) and constant-voltage operation. The loudspeaker shall have a powder coated steel back can. The baffle and the grille shall have either a white (RAL 9010) or black (RAL 9011) paintable finish with UV inhibitors to prevent discoloration. The enclosure shall retain the grille magnetically. Any logo on the grille shall be removable without leaving a blemish. The loudspeaker shall have a double-stepped long-travel dog-ear blind mounting system that can capture ceiling thicknesses from 0 to 2.25 in. The conduit cover plate shall be removable, retained by a captive Phillips head screw. A mud ring shall be provided to allow pre-installation wiring. The loudspeaker connections shall be a locking 4-pole Euro-block that accepts four 18 AWG wire pairs. The loudspeaker shall be listed as safe for use in air-handling spaces under UL1480 and UL2043. The loudspeaker shall meet or exceed IP-34 for ingress protection; it shall meet the IEC 60529 IP-X3 splash rating. The switchable transformer shall be listed under UL1876. The baffle shall meet UL94-V0 and UL94-5VB flammability ratings and shall comply with IEC60849/EN60849 safety standards. The loudspeaker's enclosure shall be 6.94 in (17.6 cm) high and 9.06 in (23.0 cm) in diameter. The loudspeaker shall weigh no more than 6.4 lb (2.9 kg). The ceiling mount 2-way co-axial system shall be the QSC AD-C4T.