Microphone Defeaters

Unauthorised audio capture has become one of the most common corporate security threats. Smartphones, laptops, meeting-room systems, covert microphones, and IoT devices can all be used to record sensitive discussions without detection. In high-risk environments, relying on participants to disable or surrender their devices is no longer enough.

Our Acoustic Microphone Blocking solutions use advanced acoustic and ultrasonic interference to prevent microphones from capturing clear speech. These systems protect conversations where confidentiality is essential — boardrooms, legal strategy sessions, HR investigations, executive discussions, contractor negotiations, and spaces where corporate leakage or insider threats pose real risk.

We supply a range of acoustic and ultrasonic blocking devices designed for different deployment scenarios:

Close-range blocking systems for one-to-one discussions, interviews, and controlled interpersonal meetings
Office and meeting-room systems that blend into the environment while protecting multi-participant discussions
Portable, wide-area units housed in discreet enclosures for securing temporary sites, travel situations, and larger open spaces up to several metres

All systems serve the same purpose:
prevent unauthorised recording and protect the integrity of sensitive speech.

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How does acoustic microphone blocking interfere with MEMS and electret microphone elements?

These systems overwhelm microphone membranes with controlled acoustic pressure and ultrasonic energy, forcing the diaphragm into non-linear behaviour. MEMS and electret capsules cannot distinguish speech from the induced interference, resulting in clipped, distorted, or completely unusable recordings. This applies equally to onboard smartphone microphones, conference systems, covert recorders, and embedded IoT microphones.

Can ultrasonic blocking penetrate directionality filters, digital noise cancelling, and beamforming algorithms?

Yes. Ultrasonic interference introduces unpredictable high-frequency artefacts that digital processing cannot isolate or cancel. Beamforming and noise suppression depend on recognisable voice patterns; once those patterns are corrupted at the diaphragm level, the DSP pipeline cannot reconstruct usable audio. This makes ultrasonic blocking effective even against advanced multi-mic arrays in modern devices.

What is the practical impact of multi-angle ultrasonic projection in recording disruption?

Multi-angle projection ensures that microphones positioned behind objects, embedded in bags, concealed in clothing, or mounted in irregular room geometry receive enough interference energy to collapse their pickup accuracy. It eliminates “shadow zones” where a single directional source would fail, and is especially important in environments where device placement is unknown or deliberately hidden.

How does acoustic masking differ from ultrasonic jamming in terms of threat coverage?

Acoustic masking targets audible-spectrum microphones by flooding the environment with layered masking noise tuned to speech-dominant frequencies. Ultrasonic jamming disrupts microphones before the audio path even enters the audible band, affecting both active and passive recording devices. When combined, they provide cross-spectrum protection against mobile devices, IoT systems, laptop microphones, covert digital recorders, and vibration-based pickup devices.

Do these systems reduce the risk of vibroacoustic or laser-based listening through surfaces?

Yes, indirectly. While these solutions are primarily designed to neutralise microphone-based threats, the acoustic energy they generate increases surface vibration noise, reducing the coherence of reflected or transmitted speech signals. This makes vibroacoustic pickups and basic laser listening systems significantly less effective, as they rely on clean surface vibrations to reconstruct speech.

Case Study : A Law Firm Strengthens Confidential Discussion Protocols Using an Acoustic Blocking System

A law firm specialising in employment and regulatory matters approached us after realising that even with strict no-device zones, modern microphones were still unintentionally entering protected discussions. They needed a way to maintain absolute confidentiality even if a device slipped through — especially during legally protected conversations.

A law firm specialising in employment and regulatory matters approached us with a challenge tied directly to their legal duty to maintain confidentiality during protected discussions.

The firm already had strict no-device zones in place — a standard practice in many legal and corporate environments.

Attendees were required to leave phones, laptops, smartwatches and audio-capable devices outside the meeting area, but in practice this became difficult:

Clients occasionally forgot devices in pockets or bags
Visiting counsel brought devices in unintentionally
Staff carried work phones that couldn’t always be surrendered
Modern microphones are embedded in almost everything

Even with strict policy, the firm recognised a problem seen across the industry: microphones still end up inside the room, and a legally protected discussion cannot be compromised under any circumstance.

The Requirement

The firm didn’t need a sweep or TSCM operation — they needed a protective layer that would:

go beyond “no device” policy
protect confidential speech even if a microphone was present
secure only the discussion zone
operate discreetly
protect against phones, laptops, wearables, covert recorders

In short: when a conversation is protected by law, the room needs a guaranteed safeguard.

Solution: BRMSK Directional Acoustic Blocking System

We recommended the BRMSK, a directional acoustic microphone blocker designed to protect conversations within a 3.5-metre zone. This ensures confidentiality even when an overlooked device is present.

Why it fit perfectly:

Reinforces the no-device policy
Neutralises all microphone types
Directional — focuses only on the discussion area
Silent, discreet and professional
Meets legal confidentiality requirements

Deployment

The system was positioned to cover the central seating zone in their primary meeting suite. Their new procedure:

Standard no-device rule remains
Meetings begin normally
BRMSK activates quietly
Protected discussion continues without disruption

This created a two-layer confidentiality structure:

Layer 1: No-device rule
Layer 2: BRMSK acoustic protection in case a device slips through

Outcome

After adopting the BRMSK, the firm reported:

A legally defensible confidentiality safeguard
Reduced anxiety around accidental device breaches
Consistent protection across all sensitive meetings
No operational disruption whatsoever
A modernised, compliance-aligned confidentiality protocol

Why This Matters for Legal & Corporate Environments

Even with strict rules, confidentiality can still be compromised by:

forgotten devices
embedded microphones in laptops
smart accessories
accidental carry-ins
covert recording devices

An acoustic blocker like the BRMSK adds the essential last layer — ensuring private speech stays private regardless of what enters the room.

Case Study : Diplomatic Use of a Portable Acoustic Blocking System

A diplomatic protection team required a portable acoustic-blocking system capable of securing sensitive conversations in public or semi-public environments where phones, microphones, and covert recorders could not be controlled. Their priority was simple: prevent information leakage during high-level political discussions.

A diplomatic protection team required a portable acoustic-blocking solution capable of safeguarding sensitive conversations held in public or semi-public environments. Unlike fixed systems used inside embassies or secure rooms, this team frequently operated in hotels, conference centres, transport hubs, and improvised meeting areas where microphones, phones and covert devices were impossible to control.

Their operational priority was clear: prevent information leakage between high-level political parties in environments that cannot be fully sanitised.

The portable unit selected provided a 6-metre acoustic-blocking radius, ran on an internal battery, and could be deployed overtly by the protection team. Its presence signalled that a protected discussion was taking place, while its acoustic output ensured that any device within range — smartphones, wearables, remote microphones, hidden transmitters, or covert recorders planted earlier — would fail to capture intelligible speech.

For diplomatic personnel, this level of protection is essential. A single leaked conversation can trigger political fallout, disrupt negotiations, or create diplomatic incidents.

The team required a device that could be placed on a table, activated instantly, and trusted to neutralise microphones no matter where they were positioned.

With the portable acoustic system, they were able to create a controlled privacy bubble anywhere: during international summits, inside hotel lobby corners, in transit, or in venues where no secure rooms were available.

The emphasis was not secrecy — it was preventing interception, misinterpretation or manipulation of sensitive dialogue between political representatives who cannot risk exposure.

This approach is now standard for their delegation: wherever the conversation moves, the acoustic shield moves with it.

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Microphone Defeaters

Case Study : A Law Firm Strengthens Confidential Discussion Protocols Using an Acoustic Blocking System

Case Study : Diplomatic Use of a Portable Acoustic Blocking System