Sonifex RB-SL2

Twin Mono or Stereo, Limiter

The Sonifex RB-SL2 is a stereo, or twin independent mono, VCA limiter for use in news-rooms and other locations where the correct level into recording equipment is required.

SKU: 105671



Sonifex RB-SL2

Twin Mono or Stereo, Limiter

Broadcasters Warehouse -

Introducing the Sonifex RB-SL2 Twin Mono or Stereo Limiter – a powerful VCA limiter designed for various applications. Perfect for newsrooms and locations where precise recording equipment levels are required, it provides valuable overload protection.

Additionally, it serves as a budget-friendly main output limiter for small-scale radio stations, hospital radio, and student radio. Featuring XLR-3 electronically balanced inputs and outputs, the RB-SL2 supports unbalanced wiring to accommodate domestic equipment outputs.

Each channel is equipped with input gain and threshold level controls, offering precise audio adjustments. By maximizing the limit threshold, you can normalize the input-output relationship using the input potentiometers. The unit acts as a buffer with gain/attenuation, allowing you to tailor the limit threshold level and recovery to your specific application.

A flashing power LED indicates the limiter’s activation. The rear panel mode switch effortlessly transitions the RB-SL2 between dual mono and stereo operation. When channel 1 (left) presets are active, they apply to both channels, providing stereo limiting for simultaneous control of left and right outputs.

Alternatively, in dual mono mode, left and right signals are independently limited, allowing the RB-SL2 to function as two separate mono limiters. Experience the exceptional performance of the Sonifex RB-SL2, delivering efficient audio level management for your professional and broadcasting needs.

RB-SL2 Diagram

RB-SL2 Block Diagram.

Technical Specification For RB-SL2

Audio Specification

Maximum Input Level: +28dBu
Maximum Output Level: +28dBu
Input Gain: Adjustable -8dB to +18dB gain
Limit Threshold: Adjustable -8dBu to +28dBu
Frequency Response: 20Hz to 20kHz ±0.1dB (600 Ω load, ref 1kHz)
Noise: -100dB unity gain, ref +8dBu output
Distortion: 0.01% THD @ 1kHz, ref +8dBu output, threshold set at +10dBu
Common Mode Rejection: >66dB typically
Input Impedance: >20kΩ balanced bridging
Output Impedance: <50 Ω balanced


Inputs: 2 x XLR 3 pin female (Balanced, can be unbalanced)
Outputs: 2 x XLR 3 pin male (Balanced, can be unbalanced)
Mains Input: Filtered IEC, switchable 110-120V, or 220-240V, fused, 6W max
Fuse Rating: Anti-surge fuse 100mA 20 × 5 mm (230VAC)
Anti-surge fuse 250mA 20 × 5 mm (115VAC)

Equipment Type

RB-SL2: Twin mono, or stereo, limiter

Physical Specification

Dimensions (Raw): 28 cm (W) x 10.8 cm (D) x 4.2 cm (H) (1U)
11” (W) x 4.3” (D) x 1.7” (H) (1U)
Dimensions (Boxed): 36 cm (W) x 20.5 cm (D) x 6 cm (H
14.2” (W) x 8” (D) x 2.4” (H)
Weight: Nett: 1.0 kg Gross: 1.45 kg
Nett: 2.2lbs Gross: 3.2lbs