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Q-CS Loudspeaker

For Finished Low-Ceiling Applications

Q-CS Loudspeaker
Q-CS Loudspeaker



Q-CS in a compact, omnidirectional loudspeaker designed for flush mounting in 8 ft. to 14 ft. finished ceilings. Its hemispherical coverage pattern creates a smoother sound field with fewer units than a system of conventional speakers. The Q-CS produces both clear voice announcements and full range music reproduction, even at background levels.

Q-CS loudspeaker produces low, mid and high frequencies equally throughout its coverage area.

The Soundsphere Q-CS has been designed to simplify installation. The one-piece unit, with its integrated 15 Watt transformer, is shipped fully assembled. No special electronic processing is necessary. Mounting accessories include a tile bridge for suspended ceilings and a steel back can for plenum applications.

For Finished Ceiling Installations Requiring: • Clear Voice Announcements • Full range music reproduction, even at background levels

Ideal for • Office Buildings • Restaurants • Bars & Nightclubs • Hotel Lobbies • Courtrooms • Classrooms • Retail & Grocery Stores • any place where high quality audio in finished ceilings is required.

With the Q-CS, you will experience superior results while using fewer units than conventional ceiling loudspeakers. These loudspeakers offer a smooth hemispherical coverage pattern, with flat frequency response and high sensitivity (89dB 1W/1m). The Q-CS utilizes Soundsphere’s exclusive patent-pending Broadband Linear Excursion Control to provide high sensitivity and accurate, articulate low-frequency performance. Each unit ships fully assembled and uses a standard tile bridge for 8 in. speakers. read more...
Q-CS Features:
  • 8 in. coaxial driver
  • Smooth hemispherical coverage pattern
  • Innovative engineering provides full frequency sound radiating 180° x 360°
  • Better coverage of all frequencies
  • Flat frequency response
  • Accurate, full range voice and music reproduction without electronic processing
  • High sensitivity (89dB 1W/1m)
  • Fewer units produce results superior to conventional ceiling loudspeakers
  • Exclusive patented Broadband Linear Excursion Control for high sensitivity and accurate, articulate low frequency performance
  • Exclusive patented Exponential Diffusion Control for smooth mid and high frequencies throughout the coverage area at any volume level
  • Integral transformer for 25V, 70V and 100V constant voltage systems
  • Unit shipped fully assembled
  • Quick and easy installation
  • Uses standard tile bridge for 8 in. speakers
  • Made in the USA
Q-CS Specifications:

Sensitivity 89 dB; 1W/1m
Maximum SPL 101 dB; 15W/1m
Power Handling 15 Watts RMS
Coverage 180° vertical
360° horizontal
Available Power Taps 25V, 70V, 100V
15W, 7.5W, 3.8W, 1.9W, 1W, 0.5W
Weight 7.25 lbs. (3.3 kg)
Size Enclosure: 7 3/8 in. dia. x 8 1/8 in. high (187mm x 206mm)
Mounting Flange: 11 7/8 in. dia. (302mm)
Grille: 12 1/2 in. dia. x 1 5/8 in. high (318mm x 41mm)
Driver Coaxial: 8 in. LF, 1/2 in. dome HF
Material ABS Resin
Q-CS Related Items:


Tile Bridge for installation in suspended ceilings 2 ft. x 2 ft. or 2 ft. x 4 ft. ceiling tiles



Plenum Can (Steel) enclosure plenum rated ceilings




Q-CS Images:

Q-CS Bedroom Application

Q-CS Video Application

How many conventional ceiling loudspeakers can be replaced by one Soundsphere Model Q-CS ceiling loudspeaker?

This question comes up every time the conversation turns to the Model Q-CS. The answer requires some discussion:

The true coverage of conventional ceiling loudspeakers
According to their specification sheets, most "higher-quality" ceiling loudspeakers produce a full-frequency coverage field (-6dB from on-axis) of 60°. Beyond this cone of coverage, mid, mid-high and high frequencies are attenuated. These frequency ranges are crucial to speech intelligibility and perceived "smoothness" of coverage.

Ceiling loudspeaker systems should never be heard
Listeners should never perceive a ceiling sound system. As listeners move around the coverage area, the sound level and frequency response should not change enough to be noticed. Conventional ceiling loudspeakers, when used conventionally, produce full-frequency sound directly under them and only low frequency sound off-axis. A listener moving from an off-axis position to directly under the loudspeaker cannot help but perceive a change in the soundfield.

So, conventional loudspeakers cannot produce a smooth, full-frequency soundfield?
Of course they can. The reason that they never produce such a soundfield is that too many loudspeakers must be used. In the case of the 60° ceiling loudspeaker in an 8 ft. high ceiling, the loudspeakers would have to be spaced 4-1/2 ft. apart to create such an effect. In a 50 ft. x 50 ft. space, this would require 11 rows of 11 speakers, for a total of 121 loudspeakers. Most conventional ceiling loudspeaker manufacturers recommend a spacing of 10 ft. for an 8 ft. high ceiling. In the the 50 ft. x 50 ft. example space, this would require 5 rows of 5, for a total of 25 loudspeakers. The resulting soundfield is what we have all experienced in ceiling loudspeaker systems. We at Soundsphere consider this result unacceptable.

Why is a system using Soundsphere Q-CS loudspeakers so much better?
The Q-CS provides full-frequency response throughout a hemisphere. Therefore, spacing of speakers is based solely on the inverse square law. For a 3dB variation in direct field level at an 8 ft. mounting height, the Q-CS can be spaced 14 ft. apart. In the 50 ft. x 50 ft. example space, this would require 4 rows of 4 speakers, for a total of 16 loudspeakers. With a conventional loudspeaker system, even using 9 more speakers would not produce the same smooth, full-frequency, diffuse soundfield that the Q-CS system does. If you really want to compare apples to apples, it would require 121 conventional ceiling loudspeakers with equalization (to reduce the low-frequency output) to equal the performance of 16 Soundsphere Q-CS loudspeakers.

Spacing in Multiple Loudspeaker Systems in Feet (Meters)

Floor to Ceiling Height
in Feet (Meters)
Direct Field SPL Variation in dB
  3 (±1.5) 4 (±2.0) 5 (±2.5) 6 (±3.0)
8 (2.5) 14 (4.3) 16 (4.9) 18 (5.5) 21 (6.4)
10 (3.0) 21 (6.4) 24 (7.3) 27.5 (8.4) 32 (9.7)
12 (3.7) 27 (8.2) 32 (9.7) 36 (11.0) 42 (12.8)
14 (4.3) 33 (10.0) 38 (11.6) 45 (13.7) 52 (15.9)
Based on nominal ear height of 4 feet (1.2M)

Floor to Ceiling Height
in Feet (Meters)
Direct Field SPL (dB) vs. Power & Mounting Height
Power per Loudspeaker in Watts
  15 7.5 3.7 2 1 0.5
8 (2.45) 99 96 93 90 87 84
10 (3.0) 95.5 92.5 89.5 86.5 83.5 80.5
12 (3.65) 93 90 87 84 81 78
14 (4.25) 91 88 85 82 79 76
Based on nominal ear height of 4 feet (1.2M)

Q CS Drawing
Q CS Drawing
Q CS Drawing

Architects and Engineers Specifications

The loudspeaker shall be a self contained, wide range device with a broad coverage pattern. The frequency response shall be 55Hz to 16kHz ± 4dB; the vertical polar coverage shall be 180° within ± 5dB. The loudspeaker shall have a minimum sensitivity of 89dB SPL at 1 Watt/1 meter, a continuous power handling capability of 15 Watts, and a rated impedance of 8 ohms. The loudspeaker shall have an integral 15 Watt transformer for 25, 70, or 100 Volt constant voltage systems. The loudspeaker driver shall be one 8 inch woofer with a 1/2 inch dome tweeter mounted coaxially. The driver shall be mounted in a cylindrical enclosure molded from ABS resin. Hardware shall be stainless or plated steel. An optional steel or aluminum bridge shall be available for supporting the loudspeaker in suspended ceiling tiles. A decorative grille shall be provided. The loudspeaker enclosure shall measure 7.375 inches (187mm) in diameter and 8.125 inches (206mm) in height. The enclosure mounting flange shall be 11.875 inches (302mm). The decorative grille shall be 12.5 inches (318mm) in diameter and 1.625 inches (41mm) in height. The complete loudspeaker shall weigh 7.25 lbs. (3.3kg). The loudspeaker shall be the Soundsphere® Model Q-CS.