A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z 

A

Active acoustics

Electronically generated background sound of a specified level and frequency content, that is introduced into occupied environments to provide masking of intrusive noises and to enhance speech privacy.

Alpha w - aw (weighted sound absorption coefficient)

A single-number rating for random incidence sound absorption coefficients determined in accordance with EN ISO 11654. With this method measured values obtained in accordance with EN ISO 20354 are converted into octave bands at 250, 500, 1000, 2000 and 4000 Hz and are plotted on a graph. A standard reference curve is then shifted towards the measured values until a "best fit" is obtained. The derived value of αw will vary between 0.00 and 1.00 but is only expressed in multiples of 0.05 eg αw = 0.65.

B

Bandraster

A wider than normal (50-150mm) exposed grid system, mainly used with lay-in planks, that can be used to define the ceiling module in linear, square or rectangular layouts. Bandraster is also used to provide location for partition systems.

Bioguard

Bioguard is a special treatment applied to Armstrong mineral and metal tiles that provides good cleanability, resistant to popular disinfectants and protection against bio-contamination, helping to prevent the buildup of mould, mildew and bacteria.’

Board

A tile edge detail used with Prelude 24mm (or Bandraster) visible grid, resulting in a flat ceiling plane.

C

CLEAN ROOM

A room for research, product assembly or health care where the air quality for dust, lint, or airborne pathogens is critical. Such areas usually have smooth room surfaces to prevent dust collections and air supply systems using HEPA filters in order to keep dust, lint, etc to a specified minimum level.

These minimum levels are categorised into ‘ISO Classes’ from ISO 9 to ISO 1.

Clip-In

A metal tile edge detail that enables the tile to be clipped into concealed suspension bars with a resulting fully concealed grid appearance but still retaining individual tile demountability and easy access to the void.

D

DNFW (weighted suspended ceiling normalised level difference)

A single-number rating of the laboratory measurement of room-to-room airborne sound insulation of a suspended ceiling with a plenum above it. The rating is determined by test methods conducted to BS EN ISO 140-3:1995 and rated in accordance with BS EN ISO 717-1:1997.

Some products may have Dncw values published. These are valid although Dnfw, which is essentially the same as Dncw, has superseded it.

Durability - High resistance to surface damage 

The ability of a ceiling tile to withstand vigorous cleaning, scrubbing or scratching.

E

EUROCLASS

The harmonised European classification for the fire reaction performance of building materials which may appear (in decending order of importance) as A1, A2, B, C, D, E or F.

F

Fire Reaction

Is the surface burning of materials and the rate at which they contribute to the growth of a developing fire within a particular area.

FIRE RESISTANCE

Is (after the fire has developed) the prevention of the fire from spreading through the building and attacking and destroying elements of structure.

FREQUENCY

The number of times per second in Hertz ( Hz) at which sound pressure waves are generated by a source.

H

Hertz (Hz)

The unit of frequency measurement. One cycle per second is one Hertz.

High Pressure Cleaning

The use of a superior quality fibreglass facing on the Parafon Hygien product means that it can be cleaned using a high pressure water spray (Max 80 bar). The application must be in the form of a fan spray of Min 30° and not a high pressure "cutting jet". The suggested minimum distance between the nozzle and the ceiling tile should not be less than 300mm and the angle of application should be 45°.

Hook-On

A metal tile edge detail that enables the tile to be hooked onto concealed suspension bars with a resulting fully concealed grid appearance but still retaining individual tile demountability and easy access to the void.

Humidity Resistance

A ceiling tile's ability to withstand levels of moisture without sagging. Standard tiles and panels are designed for installation within a normal occupancy condition range of 15 to 35°C and maximum 70%RH. When temperature and humidity resistance are expected to exceed these ranges, the use of 95% or 100% RH products should be considered.

I

ISO Classes

These are examples of a classification system for a "measured environment" known as a clean room. It limits the amount of particles greater than a specified size within a specified volume of air, as defined by the standard BS EN ISO 14644-1. The levels are measured from ‘ISO Class 9’ to ‘ISO Class 1’ – allowing for the least particles.

L

Laminated Ceiling Product

A mineral fibre product with decorative surface laminates such as glass wool scrim or polyester film.

LIGHT REFLECTANCE 

Light reflectance of a surface is its property of reflecting light. The measure of light reflectance is that fraction of the specified incident light which is reflected by the surface expressed as a percentage value.

M

MAIN RUNNER

The main support element of an exposed tee ceiling suspension system which is hung from the structure.

MicroLook

An angled, rebated tile edge detail used with Prelude 15 or Interlude HRC grid, minimising the visibility of the exposed grid system.

Microlook 90

A 90⁰ rebated tile edge detail used with Prelude 15 or Interlude HRC, minimising the visibility of the exposed grid system or with Silhouette grid making the face of the grid flush with the face of the tile.

MicroLook BE

A 90⁰ beveled tile edge detail used with Silhouette grid, making the face of the grid flush with the face of the tile, or with Prelude 15 grid.

N

NRC (NOISE REDUCTION COEFFICIENT)

A single-number descriptor for random incidence sound absorption coefficients. Defined in ASTM 423 90a, as the arithmetical average, to the nearest multiple of 0.05, of the measured sound absorption coefficients at the four one-third octave band centre frequencies of 250, 500, 1000 and 2000 Hz.

O

Octave

A frequency interval wherein the higher frequency is twice the lower frequency.

OCTAVE BAND

The audio frequency range is generally separated into octave bands as a matter of convenience, wherein each specific band is represented by its center frequency, e.g. 63 Hz, 125 Hz, 250 Hz, 500 Hz 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz, which cover most of the audible frequency range.

P

PERIMETER TRIM

A right angle shaped exposed grid section, either simple or stepped (shadowline), that is installed around the ceiling perimeter to mask and support the cut edges of tiles and grid.

Point load

A load applied to a structure which is concentrated over a very small area. For example, the hangers of an information sign suspended below a ceiling grid, impose point loads where they are attached to it.

Primary Cross Tee

A grid element that is perpendicularly inserted into the main runner to space it and form different modules sizes.

PRIVACY INDEX (PI)

A measure of speech privacy, or lack of speech intelligibility, where the PI is calculated from the Articulation Index (AI) according to the following: PI = (1 - AI) * 100%.

R

REI

A European rating that describes three basic criteria for fire resistance as REI and these are defined as: R = load bearing (capacity to provide structural stability) E = integrity (capacity to remain intact) I = insulation (capacity to maintain a defined temperature on the unexposed side of the building element). Depending upon national market legislation and test performance, these letters may also appear as RE or EI and all three combinations will be followed by a number eg EI 30, indicating the minimum time in minutes that protection can or must be maintained.

REVERBERATION

The persistence of sound in an enclosure, due to its continued reflection from the surfaces (walls, ceiling, floor, etc...), after the sound source has ceased. Reverberation is of significance in determining the quality and level of sound in an enclosure.

REVERBERATION TIME

The time, in seconds, required for reverberant sound in an enclosure to decay to one-millionth (60 dB) of its original intensity after the cessation of the sound source. Reverberation time is frequency dependent and is normally measured in one-third octave or octave bands.

Rw (weighted sound reduction index)

A single number rating of laboratory measurement of airborne sound reduction index. The rating is determined in accordance with EN ISO 717-1 from measurements made in accordance with EN 20140-3 over the third-octave band frequency range 100-3150 Hz.

S

SCRUBBABILITY / Frequent Cleaning

For applications where cleanliness is a priority, tiles may require cleaning beyond normal maintenance procedures. Ceilings with special facing material may offer superior performance. Metal ceilings may also be used for these applications.

Secondary Cross Tee

A grid element that is perpendicularly inserted into the primary cross tee to form different modules sizes.

SL2

A tile or plank edge detail, with shiplap edges on two opposite sides and used with a concealed 'T' or 'Z' grid section to provide a concealed appearance but still retaining individual tile demountability and easy access to the void.

Soft Fibre Ceilings

A mineral fibre ceiling product manufactured with a high proportion of mineral wool and finished with a painted laminated scrim decorative facing. They are therefore more porous and lower in density than 'hard' mineral wool types and this results in tiles with very high sound absorption although their sound attenuation will be moderate.

Sound Absorption

 The conversion of sound energy into heat (by friction) when passing through or striking a material or when causing a volume of air to resonate.

Sound Attenuation

A term used in relation to the room-to-room transmission of sound via a common ceiling plenum.

Sound Insulation

A general term describing the reduction of airborne and structure borne sound between separate spaces.

Sound Masking

The process by which masking sound is implemented to cover unwanted or intrusive sound (i.e. speech, equipment noise, etc.) and to enhance speech privacy.

SOUND SPECTRUM

A representation of a sound wave (time varying pressure wave) showing the frequency content and amplitude of the sound over the audio frequency range.

SPEECH PRIVACY

Refers to the lack of speech intelligibility from adjacent talkers. Several levels of speech privacy are defined in the ASTM standards, from Confidential privacy (meaning speech sounds can be heard but not understood), to Normal privacy (meaning that speech can be occasionally heard and understood but is generally non-intrusive), to Poor privacy (wherein all adjacent speech can be heard and understood). These levels can be related to ranges of PI representing each level of speech privacy.

Structural Fire Protection

The use of a tested ceiling system to provide additional fire resistance to a floor construction which has inadequate resistance of its own.

T

TEGULAR

Rebated tile edge detail used with Prelude 24 grid systems or Bandraster with Prelude 24 Cross Tees.

THERMAL conductivity (w/mk)

Ability of the material to resist the transmission of heat through it. The lower the reported number, the better is the thermal insulation provided.

U

Uniformly Distributed Load

A load applied to a structure that is evenly distributed across the area where it is maintained. For example a lay-in ceiling tile imposes a uniformly distributed load along the four flanges of the grid that supports it.

V

VECTOR

A tile edge detail, with grooves along two opposing edges, that is used with a Prelude 24mm (or 24 & Bandraster) visible grid to provide a 'semi-concealed' appearance but still retaining individual tile demountability and easy access to the void.

W

WASHABILITY / Occasional Cleaning

Ceiling tiles can be cleaned with moist cloth or sponge damped in water containing mild soap or diluted detergent.

wet felt Mineral Fibre Ceilings

Ceiling tiles or planks manufactured from a combination of the following naturally occuring, processed and recycled materials in varying proportions depending upon the tile type: mineral wool, clay, perlite, cellulose and starch mixed together in a water based process before being cured by heat. They are then finished with a water based paint, or laminated scrim and paint, decorative facing. Wet felt technology allows considerable variation in the product's density and porosity which can be used to positively influence a wide range of technical performances of the finished products.

A

Active acoustics Sound  

Electronically generated background sound of a specified level and frequency content, that is introduced into occupied environments to provide masking of intrusive noises and to enhance speech privacy.

 

Alpha w - aw (weighted sound absorption coefficient)

A single-number rating for random incidence sound absorption coefficients determined in accordance with EN ISO 11654. With this method measured values obtained in accordance with EN ISO 20354 are converted into octave bands at 250, 500, 1000, 2000 and 4000 Hz and are plotted on a graph. A standard reference curve is then shifted towards the measured values until a "best fit" is obtained. The derived value of alpha w will vary between 0.00 and 1.00 but is only expressed in multiples of 0.05 eg alpha w = 0.65. 

 

Amplifier

An electronic device that is used in sound system applications to convert a low level signal such as from a microphone or CD player into a high-power signal (rated in watts) capable of powering a loudspeaker to a high sound level.

 

Analog

In sound system applications, an analog electrical signal represents the measured sound level in its exact continuous form. Likewise, an analog device is an electronic device that processes analog signals in their continuous form.

 

ASTM E 1130

Standard test method for objective measurement of Speech Privacy in open offices using the Articulation Index. For more information, visit ASTM.org

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B

Bandraster

A wider than normal (50-150mm) exposed grid system, mainly used with lay-in planks, that can be used to define the ceiling module in linear, square or rectangular layouts. Bandraster is also used to provide location for partition systems.

 

Board

A tile edge detail used with Prelude 24mm (or Bandraster) visible grid, resulting in a flat ceiling plane.

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C

Class 1, 10, 100 etc

These are examples of a classification system for a "measured environment" known as a clean room. It limits the amount of particles greater than a specified size within a specified volume of air, using imperial units, as defined by US Fed Standard 209D. This standard (and the classification system) was subsequently superceded by US Fed Standard 209E which expresses limits in metric units and both have now been superceded by an international standard, ISO 14644.

 

CLEAN ROOM

A room for research, product assembly or health care where the air quality for dust, lint, or airborne pathogens is critical. Such areas usually have smooth room surfaces to prevent dust collections and air supply systems using HEPA filters in order to keep dust, lint, etc to a specified minimum level in accordance with ISO 14644.

 

Clip-In

A metal tile edge detail that enables the tile to be clipped into concealed suspension bars with a resulting fully concealed grid appearance but still retaining individual tile demountability and easy access to the void.

 

Cost indicator  

1 coin : lowest price / 5 coins : highest price

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D

DIRECTIVITY INDEX

A measure of the angular direction of the sound radiation from a loudspeaker, presented as a dB level either higher or lower than that which would be radiated by a spherical sound source.

 

Dispersion

Refers to the way in which sound spreads outward from a loudspeaker in a sound systems application. Dependent on the directivity index and the distance away from the speaker.

 

DNCW (weighted suspended ceiling normalised level difference)

A single-number rating of the laboratory measurement of room-to-room airborne sound insulation of a suspended ceiling with a plenum above it. The rating is determined in accordance with EN ISO 717-1 from measurements made in accordance with EN 20140-9 over the third-octave band frequency range 100-3150 Hz.             

 

Durability - High resistance to surface damage 

The ability of a ceiling tile to withstand vigorous cleaning, scrubbing or scratching.

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E

EUROCLASS

The harmonised European classification for the fire reaction performance of building materials which may appear (in decending order of importance) as A1, A2, B, C, D, E or F.

 

Exciter

The electro-mechanical device which converts an electrical signal from the amplifier into a mechanical vibration of the loudspeaker radiator, causing a sound wave to be produced with the same characteristics as the electrical signal. Also called a transducer.

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F

Fastrak

A wider than normal exposed grid system, used with lay-in metal planks, that can be used to define the ceiling module in linear, square or rectangular layouts. Fastrak is also used to provide location for partition systems.

 

Fire Reaction

Is the surface burning of materials and the rate at which they contribute to the growth of a developing fire within a particular area.

 

FIRE RESISTANCE

Is (after the fire has developed) the prevention of the fire from spreading through the building and attacking and destroying elements of structure.

 

FREQUENCY

The number of times per second in Hertz ( Hz) at which sound pressure waves are generated by a source.    

 

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H

Hard (wet felt) Mineral Fibre Ceilings

Ceiling tiles or planks manufactured from a combination of the following naturally occuring, processed and recycled materials in varying proportions depending upon the tile type: mineral wool, clay, perlite, cellulose and starch mixed together in a water based process before being cured by heat. They are then finished with a water based paint, or laminated scrim and paint, decorative facing. Wet felt technology allows considerable variation in the product's density and porosity which can be used to positively influence a wide range of technical performances of the finished products.

 

Hertz (Hz)

The unit of frequency measurement. One cycle per second is one Hertz. 

 

Hook-On

A metal tile edge detail that enables the tile to be hooked onto concealed suspension bars with a resulting fully concealed grid appearance but still retaining individual tile demountability and easy access to the void.

 

Humidity Resistance

A ceiling tile's ability to withstand levels of moisture without sagging. Standard tiles and panels are designed for installation within a normal occupancy condition range of 15 to 35°C and maximum 70%RH. When temperature and humidity resistance are expected to exceed these ranges, the use of 95% or 100% RH products should be considered.

 

Hygien - Anti-microbial Treatment

Where strictly controlled hygienic air quality is a project requirement, chemically treated tiles are available. Treament is designed to prevent mould, mildew and bacteria.

 

Hygien - High Pressure Cleaning

The use of a superior quality fibreglass facing on the Parafon Hygien product means that it can be cleaned using a high pressure water spray (Max 80 bar). The application must be in the form of a fan spray of Min 30° and not a high pressure "cutting jet". The suggested minimum distance between the nozzle and the ceiling tile should not be less than 300mm and the angle of application should be 45°.

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K

K2C2

A tile edge detail, with kerfs along two opposing edges, that is used with a concealed 'Z' grid section to provide a fully concealed appearance. Demountability of individual tiles is restricted but all tiles can be removed sequentially.

 

KERF

A groove in the edge of ceiling tile used to locate and provide support from a suspension section.

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L

Laminated Ceiling Product

A mineral fibre product with decorative surface laminates such as glass wool scrim or polyester film.

 

LIGHT REFLECTANCE 

Light reflectance of a surface is its property of reflecting light. The measure of light reflectance is that fraction of the specified incident light which is reflected by the surface expressed as a percentage value.

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M

MAIN RUNNER

The main support element of an exposed tee ceiling suspension system which is hung from the structure.

 

MicroLook

A rebated tile edge detail used with Prelude 15mm wide visible grid, resulting in a revealed ceiling plane.

 

MicroLook BE

A rebated tile edge detail used with Silhouette 15mm wide visible grid, resulting in a flat ceiling plane, or with Prelude 15mm wide visible grid, resulting in a revealed ceiling plane.

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N

NRC (NOISE REDUCTION COEFFICIENT)

A single-number descriptor for random incidence sound absorption coefficients. Defined in ASTM 423 90a, as the arithmetical average, to the nearest multiple of 0.05, of the measured sound absorption coefficients at the four one-third octave band centre frequencies of 250, 500, 1000 and 2000 Hz.

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O

Octave

A frequency interval wherein the higher frequency is twice the lower frequency.

 

OCTAVE BAND

The audio frequency range is generally separated into octave bands as a matter of convenience, wherein each specific band is represented by its center frequency, e.g. 63 Hz, 125 Hz, 250 Hz, 500 Hz 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz, which cover most of the audible frequency range.

 

Ohm

Unit of electrical resistance; e.g. most loudspeakers are typically 8 ohms.

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P

PERIMETER TRIM

A right angle shaped exposed grid section, either simple or stepped (shadowline), that is installed around the ceiling perimeter to mask and support the cut edges of tiles and grid.

 

PINK NOISE

Electronically generated sound that has equal energy in each octave band; typically used as the basis for the post-filtered signal used as masking sound.

 

Point load

A load applied to a structure which is concentrated over a very small area. For example, the hangers of an information sign suspended below a ceiling grid, impose point loads where they are attached to it.

 

Polar Pattern

The graphical representation of the coverage of a loudspeaker at various frequencies.

 

Primary Cross Tee

A grid element that is perpendicularly inserted into the main runner to space it and form different modules sizes.

 

PRIVACY INDEX (PI)

A measure of speech privacy, or lack of speech intelligibility, where the PI is calculated from the Articulation Index (AI) according to the following: PI = (1 - AI) * 100%.

 

Processor

A general term used in sound system applications to describe an electronic device that may have the following functions: signal generation, signal conditioning, equalization, and mixing.

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R

REI

A European rating that describes three basic criteria for fire resistance as REI and these are defined as: R = load bearing (capacity to provide structural stability) E = integrity (capacity to remain intact) I = insulation (capacity to maintain a defined temperature on the unexposed side of the building element). Depending upon national market legislation and test performance, these letters may also appear as RE or EI and all three combinations will be followed by a number eg EI 30, indicating the minimum time in minutes that protection can or must be maintained.

 

REVERBERATION

The persistence of sound in an enclosure, due to its continued reflection from the surfaces (walls, ceiling, floor, etc...), after the sound source has ceased. Reverberation is of significance in determining the quality and level of sound in an enclosure.

 

REVERBERATION TIME

The time, in seconds, required for reverberant sound in an enclosure to decay to one-millionth (60 dB) of its original intensity after the cessation of the sound source. Reverberation time is frequency dependent and is normally measured in one-third octave or octave bands.

 

Rw (weighted sound reduction index)

A single number rating of laboratory measurement of airborne sound reduction index. The rating is determined in accordance with EN ISO 717-1 from measurements made in accordance with EN 20140-3 over the third-octave band frequency range 100-3150 Hz.

Back to Top ^

 

S

SCRUBBABILITY / Frequent Cleaning

For applications where cleanliness is a priority, tiles may require cleaning beyond normal maintenance procedures. Ceilings with special facing material such as vinyl film offer superior performance. Metal ceilings may also be used for these applications.

 

Secondary Cross Tee

A grid element that is perpendicularly inserted into the primary cross tee to form different modules sizes.

 

SL2

A tile or plank edge detail, with special 'shiplapped' kerfs along two opposing edges, that is used with a concealed 'T' or 'Z' grid section to provide a fully concealed appearance but still retaining individual tile demountability and easy access to the void.

 

Soft Fibre Ceilings

A mineral fibre ceiling product manufactured with a high proportion of mineral wool and finished with a painted laminated scrim decorative facing. They are therefore more porous and lower in density than 'hard' mineral wool types and this results in tiles with very high sound absorption although their sound attenuation will be moderate.

 

Sound Absorption

 The conversion of sound energy into heat (by friction) when passing through or striking a material or when causing a volume of air to resonate.

 

Sound Attenuation

A term used in relation to the room-to-room transmission of sound via a common ceiling plenum.

 

Sound Insulation

A general term describing the reduction of airborne and structure borne sound between separate spaces.

 

Sound Masking

The process by which masking sound is implemented to cover unwanted or intrusive sound (i.e. speech, equipment noise, etc.) and to enhance speech privacy.

 

SOUND SPECTRUM

A representation of a sound wave (time varying pressure wave) showing the frequency content and amplitude of the sound over the audio frequency range.

 

SPEECH PRIVACY

Refers to the lack of speech intelligibility from adjacent talkers. Several levels of speech privacy are defined in the ASTM standards, from Confidential privacy (meaning speech sounds can be heard but not understood), to Normal privacy (meaning that speech can be occasionally heard and understood but is generally non-intrusive), to Poor privacy (wherein all adjacent speech can be heard and understood). These levels can be related to ranges of PI representing each level of speech privacy.

 

Structural Fire Protection

The use of a tested ceiling system to provide additional fire resistance to a floor construction which has inadequate resistance of its own.

 

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T

TEGULAR

Rebated tile edge used with Prelude 24mm (or 24 & Bandraster) visible grid, resulting in a revealed ceiling plane.

 

THERMAL conductivity (k)

Ability of the material to resist the transmission of heat through it. The lower the reported number, the better is the thermal insulation provided.

 

TRANSFORMER TAP

Refers to the power setting available on a step-down transformer (e.g. 1 watt, 2 watt, 4 watt, etc.) used in high voltage distributed sound systems (e.g. 70v, 50v, and 25v amplifier systems). 

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U

Uniformly Distributed Load

A load applied to a structure that is evenly distributed across the area where it is maintained. For example a lay-in ceiling tile imposes a uniformly distributed load along the four flanges of the grid that supports it.

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V

VECTOR

A tile edge detail, with groves along two opposing edges, that is used with a Prelude 24mm (or 24 & Bandraster) visible grid to provide a 'semi-concealed' appearance but still retaining individual tile demountability and easy access to the void.

 

Volt

Unit of potential difference or electromotive force. One volt is the potential difference needed to produce one ampere of current through a resistance of one ohm. Voltage is the driving force throughout a sound system from the microphone input to the speaker terminals.

 

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W

WASHABILITY / Occasional Cleaning

Ceiling tiles can be cleaned with moist cloth or sponge damped in water containing mild soap or diluted detergent.

 

WATT (W)

Unit of electrical power required to do work at the rate of one joule per second. One watt of power is expended when one ampere of direct current flows through a resistance of one ohm. The power capability of amplifiers and loudspeakers is given in watts, which relate to both the voltage driving the system and current handling capabilities of the devices.

 

White Noise

Electronically generated sound that has equal energy at each frequency so that the octave band level increases by 3 dB for each increase in octave; white noise is typically perceived to sound "hissy" compared to pink noise.

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