System Selection
When selecting a sound masking system, it’s important to consider the following features:
- Method of control
- Adjustment zones
- Adjustment capabilities
- Masking generation
- Zoning technology
- Timer functions
- Masking uniformity
- Installation versatility
- Scalability
- Appearance
There are a number of sound masking systems available on the market today and their performance varies dramatically in each of these areas. Asking the right questions enables you to select the system best suited to your requirements.
The method of controlling loudspeaker output and zoning impacts the cost, precision and amount of disruption associated with making changes to the sound masking system.
Ask which settings can be controlled and from which type of access point (e.g. centrally, at each speaker, analog or digital). Sound masking systems that offer centralized control over the output of individual loudspeakers and zoning make initial setup and future changes easy.
Zone size affects the ability to adjust the sound masking system’s frequency and volume to meet local needs and acoustical conditions.
Ask which zone size the system offers and whether these zones are the same for both frequency and volume adjustment. Sound masking systems that offer small zones (e.g. 1 to 3 speakers) are more flexible.
The system’s frequency and volume adjustment capabilities affect the ability to adjust the sound masking to accommodate the unique needs of each space.
Ask what kind of frequency (e.g. none, whole contour, 1 octave, or 1/3 octave control) and volume (e.g. large or fine increments) adjustment the system offers. Note the sound masking system’s adjustment flexibility is affected by the method of control and the zone size it offers.
The number of sound masking generators the system uses determines whether it will be affected by phasing (i.e. variations in the masking volume due to the canceling and reinforcement of sound waves as they meet between loudspeakers). It also dictates the number of equalization adjustment zones the system offers.
Ask how many sound masking generators the system uses and whether these are centrally located or integrated into each component installed in the ceiling.
If the sound masking generators are centrally located, the system must be designed with interlaced speakers so adjacent speakers are not connected to the same sound generator. This type of design reduces phasing, but it also involves more centralized components and additional wiring. The concern does not apply to sound masking systems featuring integrated, decentralized technology.
In addition to providing adjustment zones for masking output, most sound masking systems also provide adjustment zones for paging, timer functions and local volume switches. Systems vary widely in the degree to which they can be zoned and the method of creating those zones.
Ask how many zones the sound masking system offers. If it only provides a single zone, it will typically be necessary to install several such systems in order to provide any kind of zone control within the space. Systems that provide a large number of small zones offer the greatest adjustment flexibility.
Also ask whether the zones will be hardwired or digital. Hardwired zones require advance planning, more cabling and a contractor to re-wire the system should any changes need to be made in the future. Digital zones can be assigned and re-assigned at any time from a control panel or computer.
A timer allows the sound masking’s volume to vary in accordance with activity levels during the workday, helping to ensure effectiveness and comfort.
Ask whether the sound masking system offers a timer function and, if so, how many independent zones it supports, whether the zones are hardwired or digital, whether it provides 7-day independent schedules, whether unique schedules can be programmed for specific days of the year (e.g. holidays, summer hours workdays and special events), and the degree to which the timer function can vary the rate of volume change.
Note that some systems also offer an acclimatization or ramp-up feature, which can be used to gradually introduce the sound masking in retrofit installations.
The sound masking’s uniformity affects how noticeable it is to the occupants. Variations of more than 1 to 2 dBA can call attention to the sound and also reveal its source. Uniformity is determined by the location of the loudspeakers, the spacing between them, and the degree of frequency and volume adjustment the system offers.
Ask what range of variation the sound masking system’s specifications permit.
If the sound masking system is installed within the ceiling, also ask whether the loudspeakers will be upward- or downward-facing. Downward-facing loudspeakers, such as those used in ceiling tile sound masking systems, can be prone to significant volume variations due to a ‘spotlight’ effect. A decentralized sound masking system installed above the ceiling tiles can easily be adjusted to account for any obstructions within the plenum.
Sound masking systems differ in terms of how and where they can be installed. This affects their ability to provide coverage throughout the facility. A versatile system can be installed in areas with suspended ceilings, in areas with hard surface ceilings, in areas with no ceilings, and in both open- and closed-plan spaces.
Most sound masking loudspeakers are installed above the suspending ceiling or within the ceiling tile. But if you are planning to install the system in an open ceiling, selecting a design that features attractive loudspeakers and tidy cabling will ensure it does not detract from your facility’s design.
Note that sound masking systems installed within workstations will be limited to areas with workstations, while systems installed beneath the floor will be limited to areas with raised floors. Due to their location, these systems are also unable to provide paging, a significant secondary benefit of an in-ceiling sound masking system.
Scalability affects the sound masking system’s ability to be installed in facilities of varying size. Systems utilizing a lot of centralized equipment may not be cost-effective for smaller installations and can also pose problems in very large installations - because hundreds of square feet of core space may be required for equipment racks.
It can also be a challenge to maintain very large decentralized sound masking systems that require local adjustments be made at each loudspeaker. The ceiling will have to be accessed in numerous locations in order to reach the controls or rewire the loudspeakers.
Sound masking systems that offer integrated audio components and centralized control of individual or groups of loudspeakers are appropriate for installations of any size.
It’s important to select a sound masking system that is supported by professionals who can properly design and implement it and provide you with ongoing support.
Ask what services are offered with the product you’re considering.
|