Sound Masking Explained: Better Speech Privacy

Open-plan offices get treated with absorptive panels, the reverberation time comes down, and colleagues can still hear every word of the confidential call happening two desks away. That's not a failed treatment plan, it's a sign the room needed sound masking as well, not instead of, the acoustic panels already installed.

What sound masking actually does

Sound masking systems generate a low-level, engineered background sound, typically a gentle, broadband noise close to the frequency range of human speech, played through discreet ceiling or plenum-mounted speakers across a space. It doesn't remove or block the noise already in the room. What it does is raise the ambient background level slightly, enough that the signal-to-noise ratio between someone's voice and the room's baseline drops, making speech from a few desks away less distinct and harder to focus on, even though it's technically still audible.

Why this is different from absorption or white noise machines

Absorptive treatment reduces reverberation, how much a sound reflects and lingers in a room. Sound masking does the opposite in one specific sense, it adds sound rather than removing it, but it targets a different problem: speech intelligibility across open distances, not reverberant buildup within a room. The two work well together precisely because they're solving different parts of the same complaint. Consumer white noise machines are a crude, uncalibrated version of the same idea; a properly designed sound masking system is tuned and zoned to the specific space, calibrated to sit just above the threshold where it becomes consciously noticeable, and adjusted by zone so a masking level appropriate for an open desk area doesn't bleed disruptively into an adjacent quiet zone.

Where it earns its place

Sound masking is most valuable in open-plan offices pursuing BS ISO 22955:2021 compliance, particularly around confidential communication and focused work activity types, where absorption alone typically can't fully solve speech privacy across open desk runs. It's also common in healthcare settings, addressing exactly the reception and consulting-area privacy concern that HTM 08-01 raises, and in any workplace where overheard conversations are a genuine confidentiality or compliance issue, not just a comfort complaint.

What it can't fix

Sound masking doesn't reduce reverberation time, and it won't compensate for a room with genuinely poor absorption, that's still a job for panels and ceiling treatment. It also can't fix airborne sound transmission through a thin partition wall between two enclosed rooms, that's a structural insulation problem, not a masking one. Sound masking's job is specifically ambient speech privacy across open space, and it should be specified as one part of a broader acoustic plan, not a standalone fix.

Common questions

Will employees find the background sound distracting? A well-calibrated system is set just above the threshold of conscious awareness, most occupants stop noticing it within days, while still benefiting from the reduced intelligibility of distant speech.

Does sound masking work in a room with no absorptive treatment at all? It can improve speech privacy somewhat, but its effectiveness is significantly better in a room where reverberation has already been brought under control, the two measures genuinely work best together.

Planning a full speech privacy strategy

See our guide to BS ISO 22955:2021 or book a free survey to find out whether masking belongs in your office's acoustic plan.

Related product guides: acoustic screens, acoustic pods.