Behringer FBQ2496 Feedback Suppressor And Parametric EQ

Behringer FBQ2496 Feedback Destroyer / Parametric EQ

The Behringer FBQ2496 Feedback Destroyer Pro is a two-channel feedback suppressor and parametric equaliser for live sound systems. It listens to the programme continuously, detects the frequencies that are about to feed back and cuts them with extremely narrow notch filters, up to 20 per channel, before the audience hears a ring or a howl. Processing is 24-bit at 96 kHz, and the same filters can be set manually as a fully parametric EQ.

Key features

• Automatically locates and destroys up to 20 feedback frequencies per channel
• Ultra-fast feedback detection in under 0.2 seconds using FFT signal analysis
• Ultra-narrow notch filters, down to 1/60th of an octave
• Auto, single-shot and manual modes, plus a Panic button and set-and-forget default
• Up to 40 fully parametric filters in manual mode across both channels
• 24-bit / 96 kHz conversion with a 32-bit DSP
• Balanced XLR and 6.35 mm TRS inputs and outputs, MIDI In, Out and Thru

How the feedback suppression works

Feedback begins when one frequency in a microphone’s range starts to reinforce itself through the speakers. The FBQ2496 analyses the signal with a fast Fourier transform and reacts in under 0.2 seconds, placing a notch filter only 1/60th of an octave wide on the offending frequency and cutting it by up to 36 dB. Because the filter is so narrow, the rest of the programme, including the body of voices and instruments, is left virtually untouched. In auto mode the unit keeps monitoring and resets filters as conditions change; in single-shot mode it detects, destroys and locks each filter until you reset it.

Parametric EQ and manual control

Every filter can also be set by hand. In manual mode up to 20 fully parametric filters per channel are available, each with frequency adjustment across 20 Hz to 20 kHz, bandwidth from 1/60th of an octave to 10 octaves and gain from plus 15 dB to minus 36 dB. That makes the FBQ2496 a precise problem-solving EQ for taming room resonances, harsh microphones or a difficult stage, as well as a feedback tool. A three-digit LED display shows settings, and the open MIDI architecture allows software updates and control alongside other digital equipment.

Connections and signal quality

Inputs and outputs are electronically balanced on both XLR and 6.35 mm TRS connectors, with switchable operating level between minus 10 dBV and plus 4 dBu, and maximum levels of plus 20 dBu at the professional setting. A relay provides a true hard bypass if power is lost, so the system keeps passing audio. The published figures underline the transparency of the design: frequency response from below 10 Hz to 44 kHz, 107 dB dynamic range, total harmonic distortion of typically 0.007 percent and crosstalk below minus 100 dB at 1 kHz.

Rack format and power

The FBQ2496 is a 1U rack unit measuring approximately 44.5 x 482.6 x 190.5 mm and weighing approximately 1.9 kg, so one unit can protect both a mono main system and a monitor mix, or a stereo pair. The internal switch-mode power supply accepts 100 to 240 V at 50 to 60 Hz and draws approximately 10 W. Used after sensible microphone placement and speaker aiming, it raises the usable gain of a live system and keeps speech and music clear in rooms where feedback would otherwise set the limit.