Price: £119.95 (£99.96 net)

The NEDSP1901-PCB-MIC audio DSP noise cancelling module removes unwanted noise and interference  from noisy speech signals picked up from a microphone.


Easy to install audio DSP module will clean up you noise speech signals!

The NEDSP1901-PCB-MIC audio DSP noise cancelling module removes unwanted noise and interference  from noisy speech signals picked up from a microphone. 


The NEDSP1901-PCB module has increased sensitivity down to a few millivolts of input.  Following the DSP processor is a buffer amplifier that allows the overall input to output gain to reach up to 36dB and drive directly into a 600 Ohm load.  In its normal configuration, the NEDSP1901-PCB is set such that the module throughput gain is a nominal 1.  The gain can be increased by about 6dB using RV2 (Output Level) and should high input levels be encountered RV1 can be adjusted to attenuate high level input signals.

The NEDSP1901-PCB module also has some improved functionality which also allows it to increase the gain further up to about 30dB for use with very small signals and under normal circumstances these selectable adjustments are hidden from view by the module itself.

Not only does the module contain the ability to increase the gain by quite a lot, but it also contains an AGC (Automatic gain Control) facility that selects the gain setting continuously during operation, lending the module for use as a communications microphone Noise Reduction Module. The NEDSP1901-PCB-MIC has been created for this purpose.  The NEDSP900 module is fitted on headers giving access to the relevant jumpers that set the microphone level parameters depending on what type of microphone is being used.

Using with Microphones:
The NEDSP1901-PCB-MIC version has as separate plug in DSP module so the following types of microphones or inserts can be used with this version: Magnetic or Dynamic inserts , MEM’s Capsules, Condenser Electret (or just Electret) Capsules

The NEDSP1901-PCB-MIC module is designed to pass speech. Other signals such as data, music and morse (CW) will, to some degree pass through, but the integrity of these signals cannot be guaranteed.

Key benefits of noise cancelling intercom systems

Clear communication is critical in healthcare environments, yet background noise can often interfere with this. 

bhi Noise cancelling intercom systems actively reduce distracting ambient noise using digital signal processing. By analysing incoming audio and identifying the speech we can filter out the unwanted noise, making the speech more intelligible and easier to understand.

There are a number of benefits to improving speech in noisy medical environments. These include:

Reduced stress on the patient

In daunting settings such as when radiotherapy machines and CT scanners are in use, clear two-way conversation is extremely important. These enclosed spaces can leave patients feeling stressed and anxious. Having a clear voice on the other end to talk to them, explain instructions and reassure them helps to calm their nerves.

Instructions are able to be clearly communicated

With enhanced intelligibility, staff no longer have to strain to make out what is being said. Conversations flow more smoothly, without the need for repetition or raised voices. Instructions during procedures can be followed first time without the risk of miscommunication or errors.

Efficiencies are improved

Noise cancelling intercoms enable clear two-way communication. This helps to improve efficiency when treating patients, allowing for a smoother, less stressful appointment.

Reduced listener fatigue

The constant need to focus and decipher speech in noisy environments leads to significant listener fatigue for hospital staff over the course of a long shift. This mental strain can impede concentration, increase irritability, and ultimately jeopardise patient safety. bhi Noise cancelling intercoms identify speech and actively filter out the annoying ambient sounds that create this tiring 'cocktail party effect'. By delivering clearer, quieter audio, they allow staff to communicate with less effort. Rather than excessive concentration, conversations flow naturally and instructions are immediately understood. The result is greatly reduced fatigue and a calmer, more focused working environment. Staff stay energised and engaged, even during the most demanding shifts in busy, noisy wards.

Ideal environments

Medical imaging departments such as radiotherapy and CT scanning rely on clear communication between healthcare professionals, especially during procedures. However, the noise from these machines can make this difficult.

Radiotherapy machines produce noise levels exceeding 60dB and CT scanners can generate up to 80dB of noise during operation, caused by the rotating gantry and fan cooling systems they incorporate.

Installing noise cancelling intercoms in radiotherapy and CT scan rooms allows staff to converse clearly despite the unwanted background noise and interference. Leading noise cancelling products like the bhi noise eliminating intercom system (NEIS-RM25) are compatible with major radiotherapy equipment brands and CT scanners.

bhi products


The bhi NEIS-RM25 leverages cutting-edge Digital Signal Processing (DSP) to facilitate intelligible speech in these noisy environments. Proprietary algorithms analyse incoming *audio to identify speech signals and filter out interfering background noise in real-time. This reduces distracting machine and ambient sounds by up to 98%, leaving only the clear voice signal.

With robust desktop stations and sleek speaker units, bhi intercoms integrate seamlessly into any medical workspace. The modular design allows flexible positioning of microphones near patients. Simple CAT5 cabling enables rapid installation in imaging suites or radiation bunkers without too much disruption.

The NEIS-RM25 epitomises reliable, intelligent technology designed around healthcare's most vital need – being heard and understood.

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NEDSP1901 Low level Audio Modules

The NEDSP1901 noise suppression modules from bhi are an ideal solution for improving speech clarity in medical intercom equipment and other communication products used in noisy clinical environments.

The NEDSP1901 provides exceptional noise reduction of up to 40dB across the key 300Hz to 5KHz speech bandwidth. This allows voices to cut through loud machinery rumble, patient monitoring beeps, and other interfering hospital sounds.

With its low power draw and compact profile, the NEDSP1901 seamlessly integrates into space-constrained medical equipment in either the receive audio path or microphone path. Flexible control options allow developers to optimise noise cancellation while minimising power usage.

By actively eliminating unwanted noise and interference at the signal level, the NEDSP1901 delivers the crisp, intelligible two-way communication essential for patient care and safety. 

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Current hospitals using the bhi products


Our bhi noise cancelling intercoms are currently used in hospitals across the world and we have sold over 1000 systems since 2010. Hospitals with our products include:

  • The Cromwell Hospital London
  • Lancashire Teaching Hospital
  • Royal Sussex County Hospital
  • Nottingham University Hospitals
  • Vantage Oncology USA
  • Mercy Hospitals USA
  • Saskatchewan Cancer Agency Canada

Discuss noise cancelling intercoms for your hospital or clinic

If you're looking to improve the quality of you audio and remove background noise and interference from your medical setting, please speak to us today. We would happily discuss your requirements with you to ensure you get the right products for your hospital.

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