
  AD-C820/C821
AcousticDesign™ High-output Ceiling Mount Loudspeakers
Features
• 8" low-frequency woofer
• 1.4" diaphragm compression driver
• 200 watt continuous power rating
• 70V/100V multi-tap transformer included (system can operate in 
distributed or low-impedance mode)
• AD-C820 transducer/baffle assembly for separated backcan installation
• AD-C821 designed as a fully integrated blind-mount system
The AD-C820 and AD-C821 are acoustically 
identical and designed for music playback, 
public address and distributed audio 
in applications that require high output 
from a ceiling mounted loudspeaker. The 
AcousticDesign™ Series of installation 
loudspeakers has been designed for 
trouble free operation and versatility. Both 
models use custom designed transducers 
and crossover networks, in combination 
with an acoustically optimized enclosure 
(AD-C800BB), or as a fully integrated, sealed 
system (AD-C821). These loudspeakers 
continue the AD Series philosophy of 
bringing natural and accurate sound quality 
combined with versatility and reliability to 
high-ceiling applications.
The AD-C820 assembly includes the 
coentrant transducers, a 70V/100V 
transformer and a crossover mounted on 
an ABS baffle. When ordered as a system 
(AD-C820R SYSTEM; AD-C820S SYSTEM) 
the backbox (AD-C800BB) and a round or 
square grille are included.
The AD-821 is a fully integrated, factory 
sealed system using a “dog-ear” style 
mounting scheme. When ordered as a 
system (AD-C821R SYSTEM; AD-C821S 
SYSTEM) a set of tile rails and a c-ring are 
included as is a round or square grille.
The 8" woofer is equipped with a treated 
paper cone on a steel frame. In the optimized 
enclosure the usable low frequency of 
the system extends to 52 Hz. The 1.4" 
compression driver fires through the center 
of the woofer and is acoustically mated 
to the woofer for a smooth transition at 
crossover. The system achieves 90 degree 
axisymmetric coverage.
High-current, low tolerance network 
components provide smooth full-range, 
passive performance. The included 
70V/100V, custom designed transformer is 
optimized for low line loss as well as accurate 
and transparent acoustic performance.
The AD-C820/C821 loudspeakers measure 
91dB sensitivity (1W/1m) and at full 
continuous power are capable of producing 
114 dB SPL (1W/1m) output.
Specifications AD-C820 AD-C821
Configuration Passive
Transducers 
  Low-frequency 
  High-frequency
Frequency Range 
  Frequency Response (-6 dB) 
  Useable Frequency Range (-10 dB)
Maximum Output 
  Calculated Peak Output 
  Calculated Continuous Output
Nominal Coverage 90° horizontal and vertical 
Nominal Impedance 16Ω
Power Rating 
  RMS Power Handling 
  Recommended Max Amp Power
Sensitivity 91 dB SPL, 1W/1m
Bass Loading Ported
Transformers
  Type Custom low distortion laminated core, wide bandwidth design
  Taps 100 V: 16Ω bypass, 100 W, 50 W, 25 W
Agency Rating CE, UL 1480 (commercial/professional use) UL 2043 (air handling spaces)
Enclosure Volume AD-C800BB: 18 L (0.64 ft 3) 18 L (0.64 ft 3)
Enclosure
  Connectors Back box (AD-C800BB): ceramic block 
  Mounting Hardware Pre-installed, suspended, back box, four verti-
  Weight - Net  AD-C820: 8 lb (3.6 kg) 
Dimensions Diameter: 14.9" (379 mm)
System Packages AD-C820R SYSTEM: includes
1) All frequency ranges specified refer to measured half-space response (2 pi). 
2) Calculated maximum peak SP L at 1 m, half-space, speaker operating at rated rms power pink noise input, 50 Hz – 20 kHz.
3) Maximum input power tested in accordance with IEC recommendations; 50 Hz – 20 kHz band limiting, 6 dB signal crest factor.
1
2
3
8" (203 mm) ferrite woofer
1.4" (36 mm) neodymium compression driver
61 Hz – 18 kHz 
52 Hz – 18 kHz
120 dB SPL 
114 dB SPL
200 W 
400 W
70 V: 16Ω bypass, 100 W, 50 W, 25 W, 12.5 W
connector inputs and “through” connectors 
(rated for 400 W max). Loudspeaker Baffle  
(AD-C820): 10-pin MATE-N-LOK™ connector 
and faston connectors.
cal mounting straps. 
Loudspeaker Baffle: captive, integral  
Mounting Clamps.
AD-C800BB: 9.5 lb (4.3 kg) 
System Weight: 17.5 lb (7.9 kg)
Enclosure only Depth: 8.3" (211 mm) 
Enclosure with mounting straps  
Depth: 11.2" (284 mm)
AD-C820 speaker baffle, AD-C800BB backbox, AD-C800RG round grille 
AD-C820S SYSTEM: includes 
AD-C820 speaker baffle, AD-C800BB backbox, AD-C800SG square grille
Two 2-pin Euro-style connectors
Captive, integral Mounting Clamps. 
Insert enclosure into mounting hole, 
and tighten. Suspended ceiling Split-ring 
and Suspended Ceiling Tile Rails - sold 
separately.
16 lb (7.3 kg)
Diameter: 13.4" (340 mm) 
Depth: 11.9" (302 mm)
AD-C821R SYSTEM: includes 
AD-C821 loudspeaker system, 
AD-C800RG round grille, and set of tile 
rails and c-ring 
AD-C821S SYSTEM: includes 
AD-C821 loudspeaker system, 
AD-C800SG square grille, and set of tile 
rails and c-ring

AD-C820/C821 Dimensions 
AD-C820/AD-C821
Front
8.2"
208 mm
13.38"
340 mm
AD-C820
6.6"
168 mm
AD-C800BB
11.9"
302 mm
10.9"
277 mm
Side
0.36"
9 mm
11.5"
292 mm
13.4"
340 mm
Side
8"
203 mm
0.3"
8 mm
AD-C821
11.9"
302 mm
11.6"
295 mm
Side
11.5"
292 mm
13.4"
340 mm
0.3"
8 mm
AD-C800RG
AD-C800SG
11.8"
299 mm
14"
356 mm
14.9"
378 mm
Side
0.5"
12 mm
14"
356 mm
Side
0.5"
12 mm
14"
356 mm
Specifications subject to change without notice.
©2010 QSC Audio Products, LLC. All rights reserved. QSC and the QSC logo are registered trademarks of QSC Audio Products, LLC in the U.S. Patent and Trademark office and 
other countries. AcousticDesign is a trademark of QSC Audio Products, LLC. MATE-N-LOK is a trademark of Tyco. All other trademarks are the property of their respective owners. 
Patents may apply or be pending.
1675 MacArthur Boulevard • Costa Mesa, CA 92626 • Ph: 800/854-4079 or 714/957-7100 • Fax: 714/754-6174 
 AD-C820/C821 Spec Sheet - 09/01/10
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