Ambient Noise Sensing Microphone

An ANS detects the ambient noise to ensure the volume of any broadcast is adjusted and can be clearly heard

When designing a voice alarm system for areas of variable and fluctuating noise levels which can cause problems when it comes to audibility, Ambient Noise Sensors (ANS) are the perfect solution. Correctly placed, ANS will ensure that announcements are always clearly heard.

Baldwin Boxall ambient noise sensing microphones constantly monitor the ambient noise level within the area (or zone) and causes the volume of announcements to be automatically adjusted to an audible level, thus ensuring clarity. Background music is also adjusted to maintain the right atmosphere.

There are two ANS units available in the range, including a weather-proof unit.

Two ANS microphones can be wired in parallel, on the same input, to monitor the ambient noise over a larger area.


  • Monitors the ambient noise in a given area
  • Automatically adjusts the power of the amplifiers, depending on noise levels
  • When the area is at its quietest the level of the announcements, or music, will reduce
  • During busy/noisy periods the volume level adjusts to suit
  • Uses a dynamic microphone capsule, the output of which is amplified and converted to produce a variable current
  • Band pass filtering ensures that the system only responds to ambient noise affecting the intelligibility of announcements
  • An on-board surveillance tone generator permanently monitors the microphone capsule. A system fault will be indicated should the microphone capsule or on-board amplifier fail
  • The BVRAMB includes an option to allow one of three response speeds to be selected:
    • SLOW – the system will only respond to an average change of ambient noise
    • MEDIUM – suitable for most installations
    • FAST – the system will react to short duration changes in ambient noise
  • Two units can be wired in parallel on the same input to monitor the ambient noise over a larger area

ANS – standard unit
141mm x 81mm x 44mm

ANS – weatherproof unit
116mm x 116mm x 60mm

Key Benefits

Safe & Compliant

EN54 Certified

BS EN 54: Fire Detection & Fire Alarm Systems, is a mandatory standard that specifies requirements and laboratory testing for every component of fire detection and fire alarm system.

UKCA UK Conformity Assessed

UKCA (UK Conformity Assessed) marking on products replaces CE marking in the UK and requires that certification of construction products, such as VACIE / Voice Alarm Control & Indicating Equipment is performed by a UK-based approved body.

British Standards BS5839-8 Code of Practice
BS 5839-8 is a BSI Standards Publication code of practice providing recommendations for the design, installation, commissioning, and maintenance of voice alarm systems that automatically broadcast speech or warning tones, in response to signals from their associated fire detection and fire alarm systems.

Documentation & Downloads

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Added peace of mind with our 7-Year Warranty*

When it comes to the systems you rely upon to keep lives safe, complete confidence is the very least you should expect. That's why all new manufactured Baldwin Boxall products come with a manufacturer 7-year warranty as standard.
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7 Year Warranty

Microphones for Voice Alarm (VA) & Public Address (PA)

Touch Control

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Touch Control

Easy-to-use microphone with a touch sensitive screen for full control of a VIGIL3, VIGIL2, Eclipse4 or Eclipse5 system. Multi-function: NFC log in, select & route background music, emergency control mode and more. 

Fire Microphones

Baldwin Boxall Emergency Fire Microphones are housed in a robust, lockable steel enclosure and include a rugged, fist-held microphone console. Wall mountable and rack mounting units available.

Paging Microphones

BDM400 range of intelligent PA microphones with a variety of features to suit all installations. Suitable for connection to any of our voice alarm or public address systems – including VIGIL3 & Eclipse5.

Ambient Microphones

Ambient Noise Sensors (ANS) continually monitor the noise level (in a zone/area) and automatically adjust the volume of system broadcasts to that area – thus ensuring audibility at all times. Connect as part of any of our voice alarm systems.

Room Panels

Control Panels enable local control of audio facilities such as volume adjustment, music source selection and microphone input.

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