21-inch Cinema Subwoofer
- 1500 W, 21-inch transducer
- Frequency range extends to below 25 Hz without the need for B6 EQ filters
- DCP, DCM and SF-3 signal processors optionally available
Read the SB-15121 application note: covers the target applications of the SB-15121, as well as advantages and comparisons to other cinema subwoofer designs.
|Frequency Range 1 |
(-6 dB, half space)
(-10 dB, half space)
23.8 Hz - 250 Hz
21.5 Hz - 250 Hz
|Maximum Output 2 |
Calculated Peak at rated power
137 dB SPL
131 dB SPL
|Impedance||4 ohms nominal|
|Maximum Input Power 3 |
100 hours of 6 dB crest factor pink noise, 25 Hz–250 Hz
2 hours of 6 dB crest factor pink noise, 25 Hz–250 Hz, AES method
1500 W continuous
2500 W continuous
|Recommended Amplifier Power||3400 W continuous maximum / 1200 W continuous minimum|
|Sensitivity 2 V at 1 meter, half space||99 dB, 40 Hz–100 Hz|
|Nominal Coverage||Omnidirectional (80 Hz)|
|Transducers||One 21-inch (533 mm) high efficiency subwoofer transducer featuring a vented 6-inch (153 mm) copper voice coil on a fiberglass former. High excursion/low distortion design, with extremely high power handling and low thermal and port compression. Neodymium magnet to provide a very high force factor and linear excursion.|
|Recommended Processing||HPF at 20 Hz, minimum 12 dB/octave slope|
|Connectors||Barrier strip screw terminals accept up to #10 AWG stranded wire. Four terminals; two inputs and two parrallel outputs.|
|Enclosure||Vented enclosure with symmetrical port design, tuned to 25 Hz, constructed of medium density fibre-board and heavily braced. Features vandal resistant woofer mounting bolts.|
|Dimensions (HWD) inches||48.8 × 30 × 24|
|Dimensions (HWD) mm||1238 x 762 x 610|
|Net Weight||231 lb (105 kg)|
|Shipping Weight||257 lb (114 kg)|
1All frequency ranges specified refer to measured half-space response (2 pi).
2Calculated SPL at 1m, (half space, 2 pi), speaker operating at rated continuous power with pink noise within specified frequency range.
3Maximum input power tested in accordance with IEC 268-5 recommendations, 50 Hz–20 kHz band limiting, 6 dB signal crest factor.
Specifications are subject to change without notice.