White Paper
Sound Masking:
The key to successful office fit-out
This white paper examines how including sound masking early in office design can reduce cost, streamline the fit-out process and create an acoustically controlled workplace that supports productivity, speech privacy and acoustic comfort. It shows how a guaranteed minimum background sound level can achieve reasonable privacy between rooms without always building partitions to the slab, and how the fit-out remains acoustically adjustable as the space and its use change.
Introduction
The way we use the office has changed significantly since COVID. Hybrid working, flexible attendance and online meetings now shape how many workplaces operate. Offices need to bring people together for collaboration while also providing the privacy and acoustic comfort needed for concentration, calls and focused individual work.
These demands make flexibility and acoustic control central to effective workplace design. Occupancy and activity can vary throughout the week, with the same space accommodating lively teamwork one day and quieter individual work the next. Fewer people does not necessarily mean fewer distractions: in a quiet office, nearby conversations can become more noticeable and easier to overhear. A successful fit-out must accommodate these changing conditions while remaining practical and cost-effective to adapt.
Developed with input from acoustic consultancies, this white paper explores how integrating sound masking early in the design process can help create flexible, acoustically controlled workplaces. It examines how controlled background sound, combined with appropriate partitioning and sound absorption, can improve speech privacy, reduce distractions and support more economical construction. This approach also provides ongoing acoustic control as layouts, teams and business needs evolve.
Why do offices fall short?
Office design continues to evolve, but even carefully planned workplaces can fall short of expectations for productivity, privacy and comfort.
A central challenge is accommodating two essential activities: collaboration and concentration. People need to exchange ideas, take calls and hold conversations, often close to colleagues who are trying to focus. These activities place different acoustic demands on the same space.
Partitions, furniture, enclosed rooms and absorptive finishes all help manage this balance. Their effectiveness, however, depends on how they work together with the layout and background sound. Separating activities visually does not necessarily provide the acoustic separation needed for focused work or private conversation.
When background sound is too low, speech can remain clearly intelligible beyond the people taking part in a conversation. Nearby discussions become easier to overhear, potentially interrupting concentration and reducing privacy. The level and frequency balance of background sound therefore need to be considered alongside sound absorption and sound insulation.
Effective workplace acoustics bring these elements together as part of a coordinated design. Controlling ambient sound is a key part of this approach, helping create an environment where people can collaborate comfortably while others concentrate nearby.
What is ambient sound?
Ambient sound is the overall sound present in a space. In workplace acoustic design, particular attention is given to the underlying background sound against which conversations and other activities are heard. This may include sound from ventilation, building services and external traffic, as well as a dedicated sound masking system.
Background sound plays an important role in speech privacy, concentration and acoustic comfort. When speech stands out clearly above the background, conversations can be easier to overhear and more distracting to people nearby. An appropriate background sound can make those conversations less intelligible, helping reduce their impact on others. Its frequency balance matters as much as its overall level.
A quiet library and a busy café illustrate this relationship. In the library, a conversation can stand out sharply against the quiet surroundings. In the café, the surrounding sound may make conversations at other tables harder to follow. In an office, this principle is applied more subtly, with the aim of supporting comfortable conversation and focused work within the same environment.
Both enclosed offices and open-plan areas benefit from carefully managed background sound. Ventilation, mechanical plant and external noise can contribute to this background, but they do not automatically provide the level, frequency balance or consistency needed for effective speech masking. Air-conditioning sound can change as systems adjust, traffic noise fluctuates, and acoustic conditions can vary considerably across a floor.
Quieter building services and effective façade insulation can reduce these incidental sounds, leaving conversations more exposed where little background sound remains. Conversely, noticeable mechanical noise may still provide limited speech masking if much of its energy is concentrated at low frequencies. The existing sound therefore needs to be assessed for both comfort and its contribution to speech privacy.
Sound masking provides a means of deliberately controlling this part of the acoustic environment. Its level and frequency balance can be calibrated to suit each area, with consistent coverage across the space. Combined with appropriate layout, sound absorption and partitioning, it helps create a workplace where people can collaborate while others concentrate nearby.
From room to room
Speech privacy between rooms depends on the combined performance of the building construction and the background sound in the adjoining space. Both need to be considered from the outset, with the required level of privacy matched to how each room will be used.
Partitions, ceilings, doors and glazing help limit the transmission of speech to neighbouring rooms and open-plan areas. Construction may range from lightweight partitions terminating at a suspended ceiling to more substantial systems extending to the structural slab. The appropriate solution depends on the privacy requirement and all the routes by which sound can travel between spaces.
A partition’s laboratory sound insulation rating is only one part of this assessment. In the completed fit-out, sound may also pass through doors, service penetrations, poorly sealed junctions or a shared ceiling void. Correct detailing, sealing and installation are essential to achieving the intended performance.
Another key factor is the background sound where transmitted speech is heard. If the adjoining space is quieter than the design assumed, conversations may be easier to understand, even when the partition has been constructed correctly. A sound masking system adds a carefully calibrated background sound that can make transmitted speech less intelligible and improve privacy.
When speech privacy falls short, the consequences can include costly remedial work, disruption to occupants and loss of confidentiality. Coordinating the construction and background sound during design helps address these risks before occupancy. The completed installation should then be assessed against the required privacy outcome.
Considering sound masking early also creates opportunities to assess more economical and adaptable construction options. Where the combined design achieves the required performance, this may allow simpler partition systems and greater flexibility for future changes. As rooms and layouts evolve, the sound masking can be recalibrated alongside a review of the revised construction and privacy requirements.
Slab to slab or floor to ceiling?
Speech privacy between rooms depends on two things working together. The first is how much sound the construction blocks (Dw). The second is how much background sound is in the receiving room to cover whatever gets through. A quiet receiving room needs a better-performing wall. A room with a reliable background level needs less from the wall.
The catch is that background sound from air-conditioning isn’t reliable. It varies with load, drops away after hours, and modern quiet systems may provide very little. If the design depends on a background level nobody can guarantee, the privacy it promises may not be there on the day.
Sound masking sets a minimum. Once the background level in each room is calibrated and locked, within the comfortable range recommended in AS/NZS 2107:2016, it becomes a design value rather than an assumption. Every decibel it reliably provides is a decibel the partition doesn’t have to.
That is what the diagram shows. With a guaranteed minimum background level, partitions finishing at the underside of the suspended ceiling can often achieve reasonable privacy between meeting rooms, quiet rooms and the surrounding spaces, without extending through the ceiling void to the slab.
It isn’t a universal substitute. Rooms for highly confidential discussions may still call for slab-to-slab construction or additional treatment, as may low-performing ceiling tiles, poorly sealed doors or open return-air paths through the ceiling void. The approach works when the construction and the masking level are designed together and the result is verified on site.
Where it applies, the benefits are tangible. There is less construction and fewer services clashes in the ceiling void, the fit-out is faster, and partitions are easier to relocate when the layout changes.
Open-plan and activity-based working
Open-plan workplaces need to support two activities that often compete acoustically: collaboration and concentration. Spontaneous conversations and team discussions take place within earshot of people working on individual tasks. In hybrid workplaces, this balance also needs to accommodate online meetings and changes in occupancy.
Furniture, screens and designated work zones help organise these activities, but their effectiveness also depends on the acoustic environment. When background sound is too low, conversations can remain clearly intelligible beyond the people taking part, drawing attention away from focused work.
Carefully calibrated sound masking helps reduce the intelligibility of speech over distance. The aim is to preserve comfortable communication between nearby colleagues while making conversations further away less distinct and less intrusive. This helps reduce unwanted speech distractions and improve speech privacy across the open-plan space.
Sound masking works alongside sound-absorbing finishes, appropriate workstation spacing and well-planned activity zones. Suitably designed enclosed rooms provide settings for confidential conversations and calls that would otherwise disturb nearby workers.
Together, these measures help people concentrate while remaining connected to their team, with fewer unrelated conversations competing for their attention.
Collaboration and concentration
The diagram illustrates how controlled background sound can reduce the area over which speech is intelligible and potentially distracting.
When background sound is low, conversation from the blue speaker may remain clearly understood across the larger green area, drawing the attention of people working nearby.
With appropriately calibrated sound masking, conversations become less intelligible at a distance. The smaller red area illustrates this reduced area of potential distraction. The aim is to preserve comfortable conversation between nearby colleagues while reducing the impact on others.
By making unrelated conversations less intrusive, sound masking helps support focused work alongside everyday collaboration.
Taking control of workplace sound
Sound masking
Sound masking makes background sound a deliberate part of workplace design. It provides a controlled acoustic foundation that can be coordinated with partitions, ceilings and the layout of open-plan areas to support speech privacy and acoustic comfort.
A sound masking system distributes a carefully shaped background sound through a network of loudspeakers. Depending on the building, these can be concealed above a suspended ceiling, integrated into the ceiling or installed within an exposed-ceiling design. The sound level and frequency balance are calibrated to suit each area and its intended use.
Sound masking now has an established record in Australian workplaces and learning environments - see our projects
More efficient fit-outs
Including sound masking early allows the design team to consider background sound alongside the performance of walls, ceilings and doors. This creates opportunities to achieve the required speech privacy with more economical construction.
In suitable rooms, a coordinated design may allow partitions to terminate at the suspended ceiling, reducing materials and work within the ceiling void. At ANU’s Mathematical Sciences Institute and Research School of Social Sciences, 45dB worked with acoustic consultants WSP to integrate sound masking with the partition and ceiling design. This approach supported floor-to-ceiling construction and helped streamline the fit-out process.
The appropriate solution depends on the room’s privacy requirements and the performance of the complete acoustic design.
Flexibility as workplaces change
Controlled background sound can also support the use of demountable partition systems, giving businesses more options as team sizes, room uses and working patterns change.
When a workplace is reconfigured, the masking system can be reviewed and adjusted to suit the new arrangement. Zone controls allow sound levels and frequency settings to be changed, while alterations to room boundaries may also require changes to speaker coverage. Recalibration and performance checks help ensure that the revised spaces meet their acoustic brief.
This makes sound masking an adaptable part of the workplace, with settings that can evolve alongside the physical layout.
Supporting collaboration and concentration
In open-plan and activity-based workplaces, sound masking helps make conversations less intelligible at a distance. The aim is to support comfortable communication between nearby colleagues while reducing unwanted speech distractions for others.
It can also improve existing environments. At Monash University’s Learning and Teaching Building, 45dB installed sound masking to address speech travelling between office pods and surrounding open-plan study areas.
Together with suitable absorption, layout and enclosed meeting spaces, controlled background sound helps create a more comfortable balance between interaction and focused work.
Soundscaping for communal spaces
Music and nature-inspired soundscapes can add another dimension to reception areas, lounges, breakout spaces and cafés. Selected to suit the setting, they can help create a welcoming atmosphere and give different communal areas their own character.
Where compatible audio facilities are included, soundscaping can be integrated into the system and controlled by zone. Its content, level and coverage should suit the activity and surrounding spaces, while work areas retain the calibrated sound masking designed for concentration and speech privacy.
Summary
Sound masking makes background sound a controllable part of workplace design. When considered early alongside partitions, ceilings, sound absorption and layout, it helps support speech privacy and acoustic comfort while creating opportunities for more economical construction.
Hybrid workplaces need to accommodate collaboration, individual tasks and online meetings as occupancy and activity change throughout the day. Carefully designed and calibrated sound masking helps reduce unwanted speech distractions and provides a more consistent acoustic background for these activities.
Its value also extends beyond the initial fit-out. As business needs change, speaker coverage, zoning and system settings can be reviewed and adjusted to suit new room layouts and uses. This gives businesses an ongoing means of managing an important part of their acoustic environment.
Integrating sound masking into the wider acoustic design helps create workplaces that support conversation, concentration and comfort. Planning for that control from the outset also gives businesses greater flexibility to maintain acoustic performance as their workplace evolves.