QSC AD-C81Tw-WH 8" In-Ceiling Subwoofer

  • $325.00

The AcousticDesign Series of installation loudspeaker products from QSC expands with the new AD-C81Tw ceiling mount subwoofer system. Designed to supplement audio systems with low-frequency extension, the new AD-C81Tw is acoustically matched to the entire AD Series. Rated for 100 watts continuous power handling and able to take up to 400 watt peaks, the AD-C81Tw is a great compliment to any of the ceiling mount or surface mount AD Series models. 

The 8" woofer is equipped with a polypropylene cone for protection in humid environments. The driver features a synthetic rubber surround and works optimally with the large port to provide excellent low frequency extension below 40 Hz without undesirable port turbulence. This highly efficient design measures 92 dB SPL sensitivity. 

The AD-C81Tw has a built in passive low-pass filter set at 120 Hz. The filter is defeatable from the front baffle to allow the use of outboard crossovers. 

The baffle and mounting tabs are molded from highimpact polystyrene. The rear enclosure is heavy gauge, powder coated steel. The attractive aluminum grille is backed with an acoustically transparent white cloth. The input cup is mounted on the side of the enclosure to reduce the amount of vertical clearance necessary to install the speaker. The input cup cover features a conduit attachment point plus an additional knockout for daisy-chain wiring. Input signal connection is made with a high temperature resistant ceramic screw terminal for compliance with European safety standards. 

The AD-C81Tw is factory shipped with C-rings and tile rails for installation. New construction rings (ADCNCS) and mud rings (ADC-MRS) are also available separately. The AD-C81Tw is equipped with a 70/100 V transformer with multiple taps and an 8 ohm bypass.


  • 8-inch polypropylene cone woofer
  • Large port area for extended low-frequency performance
  • Defeatable passive 120 Hz low-pass filter with impedance compensation
  • 100 watts continuous power handling, 400 watts peak
  • 70/100 V multitap transformer with 8 ohm bypass
  • Side cable entry
Configuration Ceiling subwoofer, ported
LF transducer 8-inch (20 cm) weather resistant, polypropylene cone woofer, rubber surround
HF transducer N/A
Frequency range Useable frequency range: 28 Hz to 208 Hz

Frequency Response (-6 dB): 39 Hz to 184 Hz

Filter 120 Hz low pass, passive, bypassable
Maximum output Calculated Peak Output: 118 dB SPL

Calculated Continuous Output: 112 dB SPL

Nominal Impedance 8 ohms
Power Rating Continuous power handling: 100 W <100 hours IEC

Recommended amplifier power (loudspeakerprogram" power): 200 W

Sensitivity 92 dB, 2.83 V, 1 m, free space (4 pi)
Type Custom low distortion laminated core, wide bandwidth design
Taps (switch selected) 70 V: 60, 30, 15, 7.5 W; 8 Ohms

100 V: 60, 30, 15 W; 8Ohms

Agency rating Listed UL1480, UL2043 safe for use in air handling spaces; Transformer is Listed UL1876; Compliant BS/EN 60849 safety standards
Environmental Exceeds Mil Spec 810 for humidity, salt spray and dust; IEC 60529 IP-X3 splash rating
Material Injection molded, high impact polystyrene baffle on a steel enclosure
Finish White (paintable)
Grille Painted aluminum
Connectors Ceramic block or 4-pin Euro terminals in fire protective sub-chamber
Mounting hardware Rails and C-ring for ceiling tile installation
Weight 28 lbs.
Includes (1) QSC AD-C81Tw loudspeaker, c-ring and tile rails, round grille (white,paintable), paint mask, and connector assembbly