QSC AD-S28Tw-BK Dual 8" Surface Mount Subwoofer

  • $785.00

The AcousticDesign Series of installation loudspeaker products from QSC expands with the new AD-S28Tw surface mount subwoofer system. Designed to supplement audio systems by adding low-frequency extension, the new AD-S28Tw is acoustically matched to the entire AD Series. Rated for 250 watts continuous power handling and able to take up to 700 watt peaks, the AD-S28Tw is a great complement to any of the ceiling-mount or surface-mount AD Series models.

The dual 8" woofers are equipped with polypropylene cones for protection in humid environments. The bandpass enclosure features two chambers. One chamber is completely sealed, while the other chamber features a large port. The bandpass design allows for tight precise bass with extension down to 36 Hz. This highly efficient design produces a 1W at 1m sensitivity of 94 dB SPL. The AD-S28Tw has a built-in passive low-pass filter set at 120 Hz. 

The marine grade plywood enclosure is built to the highest standard to provide exceptional resistance to high humidity. The zinc-plated steel grille has a black foam backing, molded ABS endcaps and a rotatable logo. On the rear of the enclosure is the input cup with a hinged door to conceal the controls and input connections. Input and output nickel plated screw terminals accept wiring from 18 AWG (1.02 mm) to 12 AWG (2.053 mm). Two rotary switches can be found in the input cup. One switch selects between the 70V/100V transformer taps, while the other switch enables or disables the internal passive low-pass filter. 

The AD-S28Tw can be deployed in a number of ways. With the included rubber feet attached, the subwoofer can be floor or shelf-standing. Suspended installation is available with either the included forged-shoulder eyebolts and accessories or the included steel yoke.


  • Dual 8-inch polypropylene cone woofers
  • Large port area for extended low-frequency performance
  • Dual-chamber ported bandpass cabinet
  • Defeatable passive 120 Hz low-pass filter with impedance compensation
  • 250 watts continuous power handling, 700 watts peak
  • 70/100 V multitap transformer with 8 ohm bypass
  • Yoke mount and flying hardware included
  • Marine grade plywood construction


  • Configuration : Surface mount bandpass subwoofer, ported
  • Low-frequency transducer : Dual 8-inch (200 mm) weather resistant, polypropylene cone woofers, rubber surround
  • Frequency range [Frequency response (-6 dB)]: 42 to 165 Hz
  • Frequency Range [Useable frequency range (-10 dB)]: 36 to 205 Hz
  • Filter : 120 Hz low-pass, passive, bypassable
  • Maximum output 2 Calculated peak / continuous Outp: 124 dB SPL / 118 dB SPL
  • Maximum output 2 Calculated peak / continuous Outp: 118 dB SPL / 112 dB SPL
  • Nominal impedance : 8 ohms
  • Power rating [Continuous power handling]: 250 W (2 hours IEC)
  • Power rating (Recommended max amp power): 500 W (loudspeaker "program" power)
  • Sensitivity : 94 dB, 2.83 V at 1 m, half space (2 pi)
  • Transformers (Type): Custom low distortion laminated core, wide bandwidth design
  • Transformers (Taps): 70V: 200, 100, 50, 25 W; 8O bypass; 100V: 200, 100, 50 W; 8O bypass
  • Enclosure material: Marine grade plywood, ABS, steel grille
  • Environmental: Exceeds Mil Spec 810 for humidity, salt spray and dust; IEC 60529 IP-X4 splash rating
  • Finish: Textured black paint
  • Grille : Painted steel
  • Connectors: Four-position barrier strip; 2 in / 2 out
  • Mounting Hardware: Black powder coated steel yoke with attachment hardware; Black zinc coated forged shoulder steel M6 eyebolts; Black powder coated steel shear plates with attachment hardware; Black rubber feet with integral threaded bolt


(1) QSC AD-S28Tw loudspeaker
(1) Yoke mount
(1) Suspension hardware kit
(1) Grille backing cloth
(1) User's Manual

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