Subwoofer unit in direct radiation configuration

Compact & extremely powerful, self-powered (3000W Class-D with PFC), DSP integrated subwoofer unit in direct radiation configuration. 21” (4” voice coil) neodymium transducer.


The CLS-121S is a high-output, extremely powerful sub-bass element designed to be used in unison with the coaxial CLS-212 line array module.

It uses one low distortion 21” (4” QUATTRO in/out copper voice coil) custom speaker with double silicon spider with optimized compliance, exclusive Malt Cross Technology cooling system for reduced power compression and aluminium demodulating ring for very low distortion.

Designed to be used either as a standard sub bass unit or easily configurable in cardioid configuration thanks to integrated front & rear power connectors enable a discreet installation without any cables visible at the front of the cluster. The extra strong, especially designed internal wooden reinforcements reduce unwanted vibrations eliminating any noise, lowering distortion and delivering a clear sound. At the same time, the bass port is designed with a flare to eliminate any turbulence caused by sharp edges in the sound waves path.

The 3000W Class-D amplifier with PFC (Power Factor Correction) offers exceptional efficiency with maximum system performance whilst significantly lowering power consumption. With Thermal, short-circuit and overload protections the system module delivers an outstanding sonic performance. Coupled together with our new generation, 64 bit/96KHz processor the system electronics are yet further guaranteed not only the utmost protection but the best sonic performance.

Designed in-house by Lynx Pro Audio engineers our DSP offers the most recent advances in digital processing such as FIR filters delivering a linear phase & frequency response. The latest 32 bit/96KHZ AD/DA converters make the system one of the most advanced & innovative line arrays on the market resulting in superior sound quality.

A 2.8” IPS user interface is located on the enclosure’s back panel and has multifunction joystick control enabling the user to control, select and/or adjust parameters such as cabinet presets, gain, delay and input EQ (see user manual). Two Ethernet ports enable the system to be controlled with the OCS platform for easier alignment, monitoring and processing of the array and together with the new Rainbow 3D prediction software delivers a complete system design tool.

The enclosure is made from premium grade birch plywood and finished with a polyurea coating for longer durability & weather protection. It also has a number of dedicated accessories available and the 4 point rigging system which includes 2 front automatically rising plates and 2 rear points which enable 10 CLS-121S cabinets to be flown in a single array or together with the CLS-212.

Key features

Extraordinary high power output

Integrated Digital processor (64 bit / 96 KHz)

Front & rear audio and power connectors for cardioid applications

Ergonomic design in premium birch plywood & finished in polyurea

2.8” IPS display with multifunction joystick control

Stackable and flyable standard and/or cardioid configuration


Perfectly suited for:

→  Touring and fixed installations
→  Sports stadiums
→  Houses of worship
→  Club installations
→  Concert halls and auditoriums
→  Low frequency complement for CLS-212

Technical Data


LF:  21” Neodymiun magnet transducer. 4” quattro in/out copper voice coil, Waterproof cone treated on both sides. Malt Cross Technology cooling system. Aluminium demodulating ring for very low distortion. 1600 W (AES)
Frequency Range30 Hz – 90 Hz (preset 90 Hz)
Quasi omnidirectional
Max SPL/Peak131 dB / 137 dB
Power amplifier
3000W Class D with switching power supply & PFC
DSPInternal Lynx Processor DSPB-FL.
96 KHz / 64 bit double-precision
High performance 32 bit 96 KHz AD/DA converters 120dB
Bass-reflex direct radiation enclosure
ControlUser control interface with 2.8″ IPS and multifunction joystick controller
Control connections
USB (DSP programming)
Dual Ethernet port, Online Control System
InputBAL/ UNBAL XLR connectors analog input + loop AES/EBU digital input + loop
Nominal Voltage
100 – 240V AC @ 50-60 Hz
Operating Voltage85 – 264V AC
AC Connectors
16A Neutrik powerCON TRUE1 TOP with looping output
FinishPolyurea coating, high grade resistant paint
15 mm / 18 mm premium birch plywood
Dimensions608 x 800 x 778 mm (H x W x D) / with pins 814.5 mm (W)
64 Kg (141 lbs)

More features

Hardware for CLS-121S

The CLS-121S cabinet is constructed from 11-ply and 13-ply premium birch plywood (15mm & 18mm thickness). The enclosure is finished with polyurea coating.

Internal design

The internal structure of the CLS-121S is heavily braced for greater longevity and all parts are assembled on metal inserts with metric screws. The amplification modules & DSP are housed in a separate chamber to the drivers avoiding excessive heat & vibration, thus delivering greater efficiency and reliability.

Rear panel

The powder coated steel front panel contains connections to power and signal for cardioid operation. It is located in the grill.


The CLS-121S has three heavy duty, powder coated front grille with a special acoustic rear fabric to protect the transducers against dust and dirt.


The CLS-121S has four ergonomic handles with firm internal grip, two on each side of the enclosure, to facilitate transport, positioning and loading of the cabinets.


The 4 point rigging system with 4 retractile levers which enable 10 CLS-121S cabinets to be flown in a single array or together with the CLS-212. Fixed 0º angle.

Can be directly linked together with 6 CLS-212 through the connection system SC-CLS212/121S or more cabinets (up to 1000 kg) with the SV-CLS20 flying frame.


The CLS-121S has two transport options: a front squid cover with wheels (100mm) and a wood transport dolly.

Accessories for CLS-121S


Flying frame for 16 CLS-212 or CLS-121S.
Max. 1000 Kg

Connection system for CLS-28 together with CLS-118S


Kit to connect SV-CLS10 or SV-CLS20 flying frame and M20 plate

4 x ground stack stabilisers for SV-CLS10


Removable front transport dolly



Dolly for 2 CLS-121S



Nylon protection cover for CLS-121S with a CA-CLS121S


Nylon protection cover for 2 CLS-121S with a CA-CLS121S/2

Rain cover for CLS-118S / CLS-121S / CLS-218S
Flight case to transport 2 SV-CLS10, cables and accessories
Ball pin with thread for CLS-212 cabinet and CLS-121S

Other products from this series

2 x 8″, 1 x 8″ dual diaphragm coaxial planar wave driver, 2800W Class D

2 x 12″, 2 x 6.5″ dual diaphragm coaxial planar wave driver, 6000W Class D

1 x 18″, 3000W Class D subwoofer in direct radiation configuration 

2 x 18″, 6000W Class D subwoofer in direct radiation configuration