Every installation uses the same three-component architecture, scaled to the number of zones being treated. A single corridor outside one meeting room uses one controller and as few as two or three maskers. Multiple meeting rooms with adjacent circulation or workspace will need at least two controllers and more maskers. The components are the same; only the quantity changes.
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Maskers
Maskers are small, discreet speakers optimised to deliver the masking signal. They are mounted in the ceiling void where one exists, or directly to the ceiling surface where there isn’t a void (in which case on-ceiling maskers are used). Each masker handles approximately 4 m² of floor area or 3 linear metres of corridor.
Three types are available to suit different ceiling constructions:
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Zone controller
One controller handles up to eight maskers. It generates the masking signal, amplifies it to the calibrated output level, and distributes it to the maskers in its zone via standard speaker cable.
Controllers are typically installed in a ceiling void, a comms cupboard, or above a suspended ceiling out of sight. Each controller is independently adjustable for level and signal spectrum during commissioning, and can be set once and left; it requires no day-to-day management.
A corridor always receives its own dedicated controller, ensuring that the masking level in the primary receiving zone is independently calibrated and not shared with maskers in adjacent rooms.
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The masking signal
The signal generated by the controller is not white noise. It is a spectrally shaped broadband signal, engineered to concentrate energy in the 300 Hz to 4,000 Hz frequency range where human speech is concentrated. This profile allows the signal to mask speech intelligibility at the lowest possible overall volume.
The target output level of 45–48 dB(A) is an industry design convention, comparable to a quiet room with ventilation running. At this level, the Speech Transmission Index (STI) in the receiving space drops below 0.20: the “confidential” threshold defined in ANSI/ASA S12.70-2016 (R2025) (a US healthcare-scoped standard), below which speech ceases to be intelligible. This threshold is consistent with independent research (Hongisto, 2005).
Poor
Conversation clearly followable from outside the room.
Marginal
Frequently intelligible through the partition.
Normal
Audible but only occasionally intelligible.
Confidential
Content cannot be understood. This is the target.
Most standard commercial offices fall in the Poor or Marginal category without masking.
The classification achieved can be recorded in the commissioning report.
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Identify controller positions
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Identify masker positions
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Plan the cable route
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Install the maskers
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Install the controller(s)
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Connect the maskers
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Commission the system
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Optional: compliance survey
What about ceiling access?
Most commercial offices in the South of England have suspended ceilings with a void of at least 200 mm above, which is sufficient for plenum masker installation without any structural work. Where the void is shallower or where the ceiling is direct-fix, tile or on-ceiling maskers are used instead.
If you are unsure what type of ceiling your office has, talk to customer service. It does not affect whether masking is possible, only which masker type is used.
Lease obligations
Installing maskers does not involve any structural alteration to the building. Plenum maskers sit in the ceiling void without attachment to the building fabric; tile and on-ceiling maskers adhere to existing surfaces and are removable.
In most leased offices, a masking installation falls within a tenant’s normal fit-out rights and does not require landlord consent. We can confirm this position for your specific lease type on request.
Ongoing maintenance
Alternatively, book a compliance survey or read the science.
