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Blakeglow Sound Masking Systems

Speech intelligibility and perfect privacy

Speech intelligibility defines how clear speech communication is, and it is directly related to the reverberation time and the background noise level in a room. It can be measured in any room and analysed using computer software. It can be quantified by the Rapid Speech Transmission Index (RASTI) value which is quoted between 0 and 1. The index ranges from 0 to 1, where 0 is perfect privacy and 1 is perfect intelligibility. Theatres and auditoriums need high values, but offices and other private locations need low values to satisfy occupants

SAA: The Sound Absorption Average is a measurement of sound absorption calculated by measuring the decay rate of the sound in a reverberation room. It indicates how well a material will absorb, and therefore attenuate, a sound. Highly absorbent materials have values close to 1; non-absorbent materials have SAA values close to 0. To stop sound reflection in open-plan offices, large surfaces need to be covered in materials with higher SAA values.

Sound has to be controlled in an open-plan office to create good acoustical conditions for the occupants. Without distance or floor-to-ceiling walls and doors, office designers need to use a combination of methods to increase speech privacy and reduce acoustical distractions:

1  isolate sources and receivers by blocking sight lines between co-workers, equipment, etc..using partitions (partial-height screens)

2  absorb reflected sound with the ceiling and floor

3 reduce diffracted sound; workstation and occupant orientation and lighting fixtures

4 provide neutral background noise using a sound masking system

Sound masking should only be considered after the soft options have been exhausted

Make the ceiling sound absorbent to reduce reflections. The ceiling is the largest bare surface in an open-plan office. It extends across the entire open-plan office, making it possible for sound to reflect into every workstation

Place light fixtures, baffles, air supply diffusers, return grilles, and any other ceiling elements carefully to avoid sound reflection. Avoid spots that reflect sound directly from one cubicle to another, because non-absorbent elements mounted in the ceiling can compromise ceiling absorbency

Consider carpeting to absorb reflections and to reduce some occupant noises (typing, squeaky chair, etc.). The floor is as large as the ceiling and also reaches into all workstations. Sound propagation paths using the floor are generally blocked by partitions, desks, cabinets, chairs, and people, but carpeting can reduce the reflections that do get through. Carpet and furniture also reduce any problems created by gaps between the floor and partitions.

Use higher partitions  which better attenuate sound. Partitions can also block vertical diffraction paths if they are high. The higher the partitions (greater angle of diffraction), the quieter the sound becomes as it travels over.

Make free-standing partitions reasonably wide to reduce horizontal diffraction.

Sound-masking

Sound-masking (noise-masking) is used to increase speech privacy, and to minimise distractions from other sounds.

Sound-masking systems can be used in 'open plan' offices or where sound isolation between adjacent rooms is insufficient. This is a common problem in modern lightweight partitions.

Sound-masking (noise masking) systems are also used in preventing eavesdropping where confidentiality is important and can be integrated with acoustic insulation and other security measures. more...

Sound-masking works by an electronically generated noise being distributed throughout the space. This increases the ambient noise - 'masking' other sounds and reducing the intelligibility of speech.

Sound masking is sometimes referred to as 'pink noise system' or 'white noise system' or as 'sound conditioning'.

Sound masking sound likes, when correctly installed, is a gentle sound like air flowing through a vent, which occupants are usually unaware of the masking sound.

Sound-masking systems consist of:

An electronically generated "random" noise source

High-quality equalisers to shape the noise

Stable, high quality power amplifiers

Loudspeakers to evenly distribute the "noise" around the space

Sound-masking systems require a sound masking generator, specially selected loudspeakers which may be in the ceiling grid or in the plenum, amplifiers and equalisers. The aim is to provide a consistent level and even distribution of the ambient (masking) noise throughout the space.

BLAKEGLOW select professional products from companies such as Toa, Prase Engineering, Tanoy, Denon and Panasonic .

BLAKEGLOW systems can be invisible with latest technology loudspeakers plastered into the wall or ceiling .

BLAKEGLOW provide sound masking systems for office and call centres ..