Choosing The Right bhi DSP Noise Cancelling In-Line Unit: In-Line Module, Dual In-Line, Compact In-Line and ParaPro EQ20-DSP Comparison

At bhi, we offer four DSP noise cancelling in-line units that deliver professional-grade noise cancellation for radio communications. The In-Line Module, Dual In-Line, Compact In-Line and EQ20-DSP/EQ20B-DSP all feature advanced DSP noise cancelling technology that removes unwanted background noise by up to 40dB, dramatically improving speech quality.

Read our guide to discover the key differences between each product and understand which will work better for your needs and set up.

Module specifications and technical differences

Physical dimensions separate these modules. The In-Line Module measures 135mm × 65mm × 46mm, weighing 0.38kg, making itself the mid-size option. The Dual In-Line expands to 165mm × 78mm × 50mm with identical weight, offering maximum connectivity real estate. The Compact In-Line achieves portability at 125mm × 70mm × 37mm, weighing just 0.125kg. The ParaPro EQ20-DSP measures 145mm x 75mm x 100mm and weighs 0.58kg.

Power consumption varies between the units: the In-Line and Dual In-Line draw up to 800mA, the Compact In-Line draws 30mA and the ParaPro EQ20-DSP draws 200mA no signal or 1200mA max power. Operating voltage ranges from 10-16V DC for the In-Line and the Dual In-Line, whereas the Compact accepts 8-16V DC or 2 AA batteries and the EQ20-DSP accepts 11-15V DC. Processing latency remains consistently low across all models at 38ms.

Audio input and output capabilities across models

The Compact In-Line is a small, compact unit and was designed to be mainly used with a pair of stereo headphones, but it will drive a small mono loudspeaker or a pair of powered speakers. It will accept speaker level or line level audio signals.

The Dual In-Line caters for both speaker level or line level audio signals and has a separate stereo headphone socket, separate line level input and output socket, and a separate mono speaker output socket (7W audio), making this unit very flexible. You could listen with headphones and a mono speaker at the same time, and you could also connect a pair of powered stereo speakers or another pair of headphones to the line output socket, allowing more than one person to monitor the signal or to monitor two separate channels at the same time.

The In-Line Module has a 5W mono audio amplifier and connects between your radio and loudspeaker. The loudspeaker audio is muted when headphones are connected, and when the unit is switched off, the audio bypass feature routes the signal directly through to the loudspeaker. The In-Line Module has a three-position switch that turns the unit on and switches the noise cancellation on and off. The unit has an audio input overload LED and an audio output level adjust control.

The ParaPro EQ20-DSP is our premium unit, and the versatile audio processor is designed to enhance voice clarity and reduce background noise. It offers both line-level and speaker-level connections, making it suitable for use with a wide range of radios, transceivers, and audio equipment. The unit includes a powerful 20W audio amplifier and provides connections for stereo headphones, powered speakers, or a mono loudspeaker. Alongside its advanced noise cancellation, the ParaPro EQ20-DSP features comprehensive parametric equalisation, allowing precise adjustment to tailor the sound to your preference. It is especially suitable for those with hearing loss.

Connection flexibility from the comprehensive accessory kit, which includes audio leads and adapters, expands compatibility for different connection options.

Noise cancellation performance and filter levels

All four modules use our unique DSP noise cancelling technology. Speech is identified, and non-speech frequencies undergo attenuation based on selected filter levels. Eight adjustable levels provide noise suppression from 8dB to 40dB, with tone suppression up to 65dB maximum. The technology adapts automatically to changing noise environments in real-time without requiring manual training. The ParaPro EQ20-DSP has the added benefit of a parametric equaliser, allowing you to fine-tune the audio to suit your own hearing.

Power supply options and portability features

The Compact In-Line offers two types of power options: either two AA batteries (providing 40+ hours of operation) or an external 8-16V DC power supply.

All modules require an external 12V DC supply, and our PSU-12-2A-WW worldwide power supply provides compatible mains operation for this purpose.

Control interface and user experience design

User interfaces reflect each module's intended complexity. The In-Line Module emphasises simplicity with a three-position switch controlling power and DSP activation. Status LEDs indicate power (red) and noise cancellation (green) states. Noise cancelling level adjustment occurs through a single rotary control.

The Dual In-Line expands functionality with separate input/output level controls, combine/separate signal switching, and eight-level DSP filter adjustment. Multiple indicators monitor power, noise cancellation, and channel overload conditions.

The Compact In-Line offers two rotary encoders with integrated push buttons. Microprocessor control enables complex operations through simple interfaces. Real-time adjustment capabilities suit dynamic environments where noise conditions change rapidly.

The ParaPro EQ20-DSP features front-panel rotary controls that make it easy to set the noise cancellation level, overall volume, and EQ profile, while a clear LED display provides real-time feedback on settings. A bypass function lets you compare the processed and original audio instantly.

Accessory compatibility expands control options across all models.

Application suitability and use case scenarios

Amateur radio operators can benefit from the Compact In-Line, EQ20-DSP and Dual In-Line's dual-channel processing, enabling simultaneous monitoring of two separate radio inputs. Mobile communications favour the Compact's battery operation. Professional marine systems utilise the In-Line's robust amplification for base station applications. Each module serves specific operational requirements while maintaining bhi's signature audio clarity.

Module performance comparison

Selection depends on specific requirements: the In-Line Module suits basic noise reduction with amplification with an extension speaker, the Dual In-Line excels in complex multi-channel environments with both stereo headphones and/or an extension speaker or powered speakers, and the Compact In-Line provides maximum portability. The ParaPro EQ20-DSP is our top-of-the-range product and offers the most features for fine-tuning the audio to suit your own environment.

Shop our range of in-line modules

Whether you need the simplicity of the In-Line Module, the versatility of the Dual In-Line, the portability of the Compact In-Line or as many features as possible with the ParaPro EQ20-DSP, bhi has the perfect DSP noise cancelling solution for your setup. Browse our complete range of DSP noise cancelling modules today, or contact our team for personalised recommendations based on your specific requirements.