Understanding Sound Masking Systems
Sound masking is the addition of generated sound into an environment to mask unwanted sound. It is significant and prioritizes modifying the background sound; however, there is substantial evidence produced and published by Banneker (BBN) and Kavanaugh indicating that acoustical satisfaction within a space cannot be guaranteed without consideration of the three principal parameters of architectural acoustical design, formalized and established in the early 1900s by Sabine.
Sound masking relies on auditory masking and can reduce or eliminate the perception of sound. Note that sound masking is not a form of active noise control (noise cancellation technique). Sound masking is applied to an entire area to improve acoustical satisfaction, thus improving the acoustical privacy of the space. Sound masking means controlling background sounds in a developed environment.
Various organizations (ASTM, ASA/ANSI, GBI, LEED, ASHRAE, WELL, etc.) define unique categories for labeling acoustical zones with purpose and/or function. A sound masking system can be used to reduce the impression of intruding sound (reducing annoyance, distraction) and improve acoustic privacy (including speech privacy).
Sound masking systems are often relied upon as a basis of design with Sound Transmission Class (STC, as supported by ASTM E336) or Noise Isolation Class (NIC, as supported by ASTM E336) to ensure an appropriate level of privacy between contiguous rooms. Sound masking is an effective solution in masking intruding noise.
In general, the purpose of a sound masking system is to provide for greater conversational privacy (and therefore improved productivity for those not involved in the conversation) in an open office environment by adding ambient noise and shaping the noise signal to mask speech. The noise signal is fed from a specially designed generator and amplifier to the sound masking (SM) speakers.
What is a sound masking system? Many people believe electronic sound masking systems cancel unwanted sounds but that’s not the case. Unlike technology used in some headphones (which cancels unwanted sounds in the confined space of an ear muff), that technology does not work on the scale of an open room. Instead electronic sound masking systems add ambient noise to an open area.
Affordable and innovative, sound masking has helped businesses everywhere achieve the silence and privacy they require. As a provider of sound masking systems, Aufderworld is happy to tell you all about this groundbreaking product and show you what it can do for your business.
While it may seem counterintuitive to drown out sound with more sound, the frequencies emitted by sound masking technology match the frequency of human speech, allowing them to muffle conversations and other distraction-inducing sounds. Sound masking systems are useful for a variety of reasons; they can block noise as well as provide white noise if a space is too quiet.
A specially filtered audio signal, described by the NC-40 Contour, increases ambient noise to effectively mask speech, making it more difficult to be understood.
What’s Sound Masking Noise?
Electronic sound masking systems are often called “white noise systems” or “pink noise systems” but neither term is technically correct. White noise (for audio use) is defined as “equal sound energy at each frequency over the usable audio spectrum.” Pink noise is defined as “equal sound energy per octave over the usable audio spectrum.”
By definition an octave is a doubling of frequency, so between 20Hz and 40Hz is an octave, between 40Hz and 80Hz is an octave, and so on. That means that compared to white noise, pink noise has much less energy in higher frequencies than it does at lower frequencies. Since human ears work in a logarithmic manner, pink noise sounds flat to the human ear, while white noise sounds overly bright.
In other words, because of the nature of human hearing, to us it sounds like pink noise has as much energy in low frequencies as high frequencies even though that is really not the case. A sound masking system doesn’t use white or pink noise but instead incorporates a very specific filtered noise (described by the NC-40 Contour) that has been proven scientifically to produce the maximum speech-masking effect.
Sound masking seeks to reduce the intelligibility of sound from a source by reducing the signal-to-noise ratio. Several cases exist where sound masking has been successfully installed for exterior applications, the most common target of concern being roadway noise. In one example application, a large artificial waterfall was constructed as part of the garden exterior of an urban hotel in Santa Rosa, California.
What Does SM Noise Sound Like?
Adding sound to a space actually makes the space seem quieter. It sounds counter-intuitive but it’s true. This is because the added sound reduces the intelligibility of human speech. Sound masking is an ambient sound, similar to the sound of airflow, that’s specifically engineered to the frequency of human speech you can target conversational distractions and make them less distracting.
Unlike white noise, sound masking is specifically engineered to match the frequencies of human speech and to sound comfortable, even pleasant, to the human ear.
Sound masking isn’t just about dropping in a few speakers-it’s about building a consistent noise floor that improves speech privacy & focus. Poor design creates “hot spots,” uneven coverage, and wasted budget. The right outcome depends on three levers: the masking type (direct vs. diffuse), speaker layout/spacing, and smart zoning.
According to the International Facility Management Association (IFMA), maintaining consistent background sound levels is essential for speech privacy and occupant comfort. At Commercial Acoustics, our engineers develop sound masking layouts that balance coverage, cost, and comfort-complete with speaker counts, zoning recommendations, and stamped design documents. To create a consistent background noise that reduces distractions and improves speech privacy.
Direct-field systems work best in smaller offices or spaces with uniform ceilings. Analog is ideal for smaller offices under about 10,000 sq ft-it’s simple and cost-effective. Most offices perform best with roughly 15-16 feet between speakers, about 225 sq ft per unit.
Your office space is a dynamic environment where ambient noise levels and the amount of distractions vary a great deal depending on the schedule and activities underway. It's the mid-morning rush at work and the office is buzzing with activity, conversations and potential distractions? The sound masking volume gently goes up. That mid-morning rush ends and the office space goes practically silent?
The sound masking volume decreases back to where it was before the rush. And it'll continuously move up and down like that: up to its maximum allowed level, down to its minimum effective level, and anywhere in between, in reaction to changes in office activity level over time. Simple enough?
Adaptive volume makes use of ceiling-mounted noise sensors and the advanced signal-processing technology embedded in our controllers to automatically adjust the sound masking volume up or down based on how loud or quiet the office gets throughout the day. While adaptive volume makes sense in most office sound masking applications, our system still includes a timer function just like the older sound masking technologies out there.
The greatest challenge in any sound masking project? To generate the recommended ideal sound masking spectrum while taking into consideration the space's unique design attributes. Room size, ceiling type, acoustic tiles, wall finishes, and office furniture all have an impact on how efficient sound masking is at drowning out distractions and improving acoustic privacy.
Our system's automatic equalization process allows it to adapt itself to an endless array of office environments. It analyzes the acoustic response and the background noise in the space covered and uses this data to figure out the spectrum needed to generate a soft, neutral and pleasant masking sound. Did we say minutes? Actually, our patented technology makes it possible to calibrate individual sound masking zones in less than a minute, with equalization done in both 1/3 octave and 340 narrow band spectra.
The quality of calibration is assessed in real-time by our system’s integrated frequency analyser. Soft dB's networked sound masking system and installation plan met our challenging office space requirements. Soft dB sound masking combines both the flexibility of networked systems and the cost efficiency of more traditional centralized systems. It can simultaneously distribute sound masking, paging and ambient music throughout an endless array of distinct office zones-each of which with their own specific volume levels, input mixing and EQ settings-across multiple office floors or buildings even.
Volume control, equalizer settings, paging/music input mixing, schedule programming: the software lets you apply every imaginable adjustment instantly on a system-wide or per zone basis. Whether you're building something new or retrofitting an existing office space, we'll make sound masking one of the simplest parts of your project. Tell us about your project.
Applications of Sound Masking
Sound masking is useful for reception areas, pharmacies, waiting rooms, and financial institutions. Sound masking is provided in the area where conversations should not be heard - not necessarily in the area where the conversation is taking place. For instance, a psychiatrist would not want those in the waiting room to overhear a private conversation with a patient, so sound masking is provided in the waiting area, but not in the psychiatrist's office.
Open Office Plans
Open office plans - open offices can be either too quiet (where someone dropping a pen in the next cubicle is distracting) - or too noisy (where the conversations of others in the office make it impossible to concentrate).
Private Offices
Private offices - private offices and other enclosed spaces often appear to provide privacy but do not. Many times, walls are lightweight and do not extend to the ceiling deck, but only to the ceiling tile. In these cases, sound can easily travel through partitions or over the walls.
Types of Sound Masking Systems
Typically, these speakers are positioned out of sight above ceiling tiles in plenum space, although speakers are sometimes used in open architecture truss type ceilings. Sound masking speakers, generators and amplifiers are typically sold separately.
Classic (Analog) vs. A classic sound masking system is ideal for offices under 10,000 square feet because it’s simple, affordable, and field-tuned during setup. Digital sound masking, on the other hand, is built for larger projects - offering programmable zones, remote adjustments, and integration with paging or mass-notification systems. Plenum installs keep hardware invisible while ACT diffuses sound evenly. If budgets are tight, spacing can stretch toward 1.7 × (2D + H − 4), but uniformity drops. Good sound masking system design keeps spacing consistent and tuning balanced.
Masking isn’t just an office play. Analog keeps hardware simple & labor light. Use closer spacing near reception or glass-heavy areas to avoid level dips. Good sound masking system design keeps analog layouts efficient-consistent spacing, clean zoning, and predictable coverage. Networked control speeds commissioning & reconfiguration. Keep on-center spacing near 15-16 ft even if the formula yields higher numbers; large floors benefit from tighter grids. Leverage presets for departments with different noise profiles (sales vs. Over-spacing: Pushing beyond ~16 ft O.C. Great hardware can still flop with poor layout, missing zones, or no commissioning plan.
Plenum Sound Masking Systems
The plenum is the space between a "dropped" ceiling and the upper deck to the floor. In plenum sound masking systems, which employ a network of loudspeakers located completely within the plenum, were the first such systems developed and have been in use since the 1960s.
Plenum-based speakers typically range 4-10 inches (10-25 cm) in diameter and generally face upwards, towards the upper deck. This is done to reflect sound from the speakers to broaden, as much as possible, the footprint from the speaker in the work area. As with any commercial-grade sound masking system, an in-plenum sound masking system requires proper layout design, commissioning, and verification of the performance.
Disregarding the importance of any of these stages in implementation will result in a sound masking system that does not perform according to the specifications of an acoustician. Only the most sophisticated sound masking systems can control the background sound level and spectra of masking sound accurately and precisely throughout a space, made possible only with the smallest zones (spatial limits around a speaker) and sophisticated electronics and software.
Uniformity can be achieved by adjusting the acoustic output of individual or a small groups of speakers. Adjustments routinely include changes in the output volume and output spectra of individual speakers.
Direct Field Sound Masking Systems
Direct field sound masking systems have been in use since the late 1990s. The name takes after the mechanics of sound transmission which considers the "direct sound path" from the loudspeaker emitted towards the recipients (listeners) underneath.
Initially used as an accessory for open office cubicles, direct field systems have been fully integrated into at least one open office furniture system and have been designed to be installed both in dropped ceilings and in offices without any absorptive ceiling systems. When installed in dropped ceilings, direct field systems use speakers that are mounted facing down.
When a ceiling tile is not available, they are mounted facing down on any available structure, sending the masking noise directly into the intended space. Theoretically, a direct field system would benefit from speakers that are omnidirectional, meaning that they transmit energy equally in essentially all directions. However, direct field systems require tighter arrays of loudspeakers given the polarity of the emission of sound.
Benefits of Sound Masking Systems
Does your company’s open floor plan make it difficult to have private conversations? Have your employees complained about noise levels being a distraction while they’re trying to work?
Yes. Sound masking is one of the easiest acoustic systems to retrofit since speakers sit above the ceiling grid or on decorative mounts. For government organizations or industries such as healthcare, privacy is not only important, but a legal requirement.
We’ve all been asked to concentrate in less-than-ideal environments. It doesn’t do good things for our working efficiency! You want to enhance worker comfort. In addition to decreasing efficiency, excessive noise can also wreak havoc on your workers’ emotional wellbeing. Stress from constantly being asked to perform in less than ideal conditions can tank worker morale. A sound masking system makes sure this doesn’t happen.
When you think of pollution, noise probably isn’t something that comes to mind-you most likely picture fuel emissions or oil spills. When your workers don’t have to deal with as much unwanted sound thanks to a sound masking system, you could potentially help them dodge some of these disastrous aftereffects of an uncontrolled office space.
We’d hazard a guess: absolutely! Absolutely any business can benefit from improved worker comfort and improved efficiency-yes, even those with open office plans. The short version, though: this type of layout, while great for collaboration, isn’t always conducive to a productive and comfortable working environment in all cases. With a sound masking system, though, you create a distraction-free workspace in which everyone can work at the noise level that best suits them.
Aufderworld designs and installs sound masking devices so employees can be more efficient, and guests and tenants can block out distracting noises from others.
Here’s a table summarizing the key differences between plenum and direct field sound masking systems:
| Feature | Plenum Sound Masking | Direct Field Sound Masking |
|---|---|---|
| Speaker Placement | Above ceiling, facing upwards | Below ceiling, facing downwards |
| Installation | More complex, requires plenum space | Simpler, can be installed without plenum |
| Sound Distribution | Reflected sound, more diffuse | Direct sound, more directional |
| Coverage | More uniform in large areas | Best for smaller, uniform spaces |
| Cost | Potentially higher due to installation | Potentially lower due to simpler installation |