Description
Perfect tonal reproduction—and everything else in the vicinity—the CELTO Acoustique SU221 delivers a monumental 3600W RMS (14400W peak) with controlled extension down to 28 Hz and impressive 102 dB/1W/1m efficiency.
This flagship vented dual 21" subwoofer sets the standard for multi-purpose touring and large-scale permanent installations requiring ultimate low-end authority.
Designed for stadiums, festivals, arenas, concert halls, and premium nightclubs where flawless, powerful bass is the foundation of the experience.
Twin custom 21" CELTO drivers with ±15 mm linear Xmax and patented DCS cooling system provide extraordinary excursion and minimal compression under extreme demand.
Heavily braced Baltic birch plywood cabinet with tongue-and-groove assembly and rubberized PolyUrea finish guarantees dynamic, resonance-free performance.
Capable of 137 dB RMS / 143 dB peak SPL with precise, musical character throughout its range.
Dual M20 sockets and genuine Neutrik Speakon connectors support flexible array configurations and rapid deployment.
Optional padded bag, pole bar, and castor kit ensure touring-ready protection and mobility.
The SU221 affirms its position as the pinnacle of the SUBIUM series—delivering bass that doesn't just support the music, it defines it.
Key Features
- Multi-purpose touring vented subwoofer
- Down to 28Hz and still 102dB/1W/1m Efficiency
- Real 3600W RMS power capacity
- Premium 2 x 21” LF drivers with massive ±15mm linear Xmax
- Patented DCS cooling system for low power compression
- Heavy braced cabinet for vibration free dynamic response
- Touring grade Rubberized black PolyUrea finish
Applications
Touring
Engineered to endure
Technical specifications
| Speaker type | Vented Subwoofer |
| Power Handling (AES standard) | 3600 W RMS / 14400 W peak |
| Nominal impedance | 4 ohms |
| Average sensitivity | 102 dB / 1 W / 1 m |
| Maximum SPL (calculated) | 137 dB RMS / 143 dB Peak |
| Frequency response (-6 dB no preset) | 28~1500 Hz |
| Nominal directivity (-6 dB) | Omni in usable range |
| Cabinet |
Exterior grade Baltic Birch Plywood Heavily braced with Tongue & Groove |
| Cabinet finish |
Touring Grade Rubberized PolyUrea Black coating Acoustic PU foam behind Front grill |
| Floor monitor use | N/A |
| Flying hardware | No |
| Mounting hardware | 2pcs M20 thread socket |
| LF |
21" CELTO ACOUSTIQUE 21SW1800-8 (2pcs) |
| Woofer Chassis | Die Cast Aluminium |
| Woofer Voice coil diameter | 4.5" / 115 mm long throw |
| Crossover | No, active mode only |
| Connectivity |
Genuine NEUTRIK 2pcs Speakon NL4 mP |
| Speaker size (HxWxD) | 588 x 1226 x 805 mm |
| Speaker Weight | 104 kg |
| Shipping information |
117 kg 710 x 1380 x 915 |
| Accessories |
CSW221-SBAG (padded cover bag) CPC-70 (pole bar with crank) SUBWHKIT100C (castor wheel kit) |
Product files
| Name | Category | Type | Size | |
|---|---|---|---|---|
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CELTO_CPC-70_A0_20250721_WEB_CAD
CELTO_CPC-70_A0_20250721_WEB_CAD
|
CELTO_CPC-70_A0_20250721_WEB_CAD | 33.1 KiB | Download | |
|
CELTO_SU221_A0_20250712_WEB_CAD
CELTO_SU221_A0_20250712_WEB_CAD
|
CELTO_SU221_A0_20250712_WEB_CAD | 115.5 KiB | Download | |
|
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD
|
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD | 37.1 KiB | Download | |
|
CELTO_SU221_A0_20250712_WEB_CAD
CELTO_SU221_A0_20250712_WEB_CAD
|
CELTO_SU221_A0_20250712_WEB_CAD | DWG | 999.1 KiB | Download |
|
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD
|
CELTO_SUBWHKIT100C_A0_20250721_WEB_CAD | DWG | 740.1 KiB | Download |
|
CELTO_CPC-70_A0_20250721_WEB_CAD
CELTO_CPC-70_A0_20250721_WEB_CAD
|
CELTO_CPC-70_A0_20250721_WEB_CAD | DWG | 781.7 KiB | Download |
Expand your system
The SU221 does wonder when combined with these other products from our range
