Compact In-Line

Price: £189.95 (£158.29 net)
Compact In-Line DSP noise cancelling module

Remove noise and interference so you can hear clearly....for a stress free listening experience!

High-performance audio processing

Easy to use with "real time" DSP noise cancelling. This compact DSP noise cancelling in-line unit is designed mainly for use with headphones although it will drive a small passive speaker.  For louder audio powered spakers will be required.

Works with both mono and stereo signals:
The bhi Compact In-Line module is a lightweight DSP noise cancelling unit made from tough impact resistant black ABS plastic, making it suitable for portable use. The unit is easy to set up and accepts either mono or stereo signals on the input and you can either connect headphones or loudspeakers to the output, so that you can enjoy your listening experience straight away.  This intuitive microprocessor controlled unit has two rotary encoders with push buttons that perform all the functions, enabling you to change the settings quickly and easily in "real time" to suit your current operating conditions.

High-performance audio processing:
The powerful high-performance audio processing system and unique DSP noise cancelling algorithm is able to distinguish the speech from the noise and interference within the audio signal.  This results in clear intelligible speech under most conditions and works especially well on weak signals.

Compact In-Line connections:
The Compact In-Line module can be powered from a separate 12V DC power supply using the fused DC power lead supplied (a plug-in DC wall wart requires a 2.1mm to 1.3mm adapter plug), or by two AA alkaline or NiMH batteries for portable mobile use. Input connections are made via the separate 3.5mm speaker level and line level audio input sockets.  The output socket can drive a pair of stereo headphones, a mono loudspeaker or a pair of powered stereo speakers.  

Simple control of all functions:
The Compact In-Line functions are microprocessor controlled by two rotary encoders with pushbuttons.  The unit can be adjusted in "real time" to suit your own noisy conditions. The “Power/Volume” control switches the unit on and off and adjusts the audio volume.  The “Filter Level” control adjusts the filter level in "real time" enabling you to respond quickly to changes in conditions.  Press the filter button to hear the difference!  You can also select between a single mono signal or stereo mode.  The Compact In-Line is particularly useful for portable/mobile use as it can be powered by 2 x AA batteries.  The unit is suitable for use on all radios and receivers and software defined radios (SDR), including Elecraft and FlexRadio products. 

Read the excellent article of this unit by Jock Elliott KB2GOM in the SWLing post online click here

Boost your audio
Why not boost your receive audio even further and use one of our EQ20 10W parametric equaliser units with your Compact In-Line. Simply connect the "Phones Out" signal to the the input of the EQ20 and connect your passive speaker or headphones to the EQ20 output.  You will be able to fine tune your audio to suit your own hearing.  This is especially useful if you suffer with hearing loss.


  • Latest bhi world-class DSP noise cancelling technology 9 to 40dB
  • Powerful high-performance audio processing system
  • Ultra low latency of 32mS
  • Processed speech much clearer and more intelligible
  • Simple easy to use with "real time" control of all functions
  • Use with headphones,a passive speaker or powered speakers
  • Mono or stereo inputs
  • LED overload indication
  • Ideal for portable use, DXing, and special event stations
  • Over 40 hours battery life with 2 x AA alkaline or AA NiMH batteries
  • Dimensions: L125mm x W70mm x D37mm
  • Unit made from tough impact resistant black ABS plastic


Power Supply:
External supply: 8 to 16V (nominally 30mA, max 350mA peak)
Reverse polarity protected
Internal batteries: Type: AA x 2 (Alkaline or NiMh recommended)
Reverse polarity protected
Low battery indication threshold: 2.1V ±0.1V
Low battery indication: LED colour changes to red.
End-of-life threshold: <1.5V
Life: 40 hours typical (Alkaline or 2500mAH NiMh).
Auto power-off: 60 minutes if input signal < 60mVpk-pk
Auto power-off can be disabled if desired.

Audio Inputs
Speaker level in: Stereo or Mono
Input Impedance: ~7 Ohms
Max withstand input power: 2 Watts RMS per channel
Max input amplitude: 3.9Vpk-pk
Line level in: Stereo of Mono
Impedance: 6.7k Ohms typical
Max input amplitude: 1.6Vpk-pk
Overload indication: LED flashes for at least 3 seconds

Audio Outputs
Phones out: Stereo or Mono
Impedance: > 4 Ohms (Can also be used as Line Level output).
Max power output: 0.2 Watts RMS per channel
Volume levels: 16 levels in 3dB steps.

DSP Noise Filtering
Powerful High-performance audio processor
Modes: Enabled / Disabled (DSP filter off)
Levels: 8
Noise suppression: 8 to 40dB
Tone suppression: Up to 65dB
Ultra low latency of 38mS

Size & weight
Size 125 x 70 x 37mm
Unit weight 0.125Kg
Case made from tough, impact resistant black ABS plastic