Glossary of terms

noise through wall

Sound Insulation – the characteristic of a material or construction to reduce noise levels, commonly known as ‘soundproofing’. Typically these materials are heavy, thick and rigid or you can use products such as Maxiboard, Acoustilay or SoundBlocker to reduce noise.  Sound insulation is used to minimise disturbance, maximise privacy and in general to allow adjacent spaces to be used without disturbing each other.  SRS specialise in providing solutions to the obvious and maybe less obvious soundproofing problems that can arise.

Sound Absorption – materials that reduce echo or reverberation, frequently marketed with the word ‘acoustic’ but importantly not to be confused with sound insulation or ‘soundproofing’. These materials tend to be light and thick, foams or mineral wool are excellent absorbers of sound. Absorbers are used in large, airy spaces with predominantly hard surfaces where speech intelligibility is critical such as classrooms, halls or call centres. Our Sonata range of acoustic panels are the UK’s most effective absorbers available but we also produce Coustifoam for projects where the functional black appearance will also be acceptable.  SRS are able to calculate the extent of a reverberation problem and provide a solution that offers the optimal performance for a given space.

Airborne noise – noise transmitted through the air to then pass through walls or floors causing disturbance, example include music, speaking etc. If you can hear your neighbours voices or TV then you are hearing airborne noise.  Solutions include MaxiboardAcoustilay, and Maxideck

Impact noise  –  noise transmitted through floors to the rooms below, not applicable to walls. Examples include footfall, treadmill noise or enthusiastic piano playing.  Solutions include Acoustilay, Acoustilay Tilemat, Impactafoam, SubPrimo or Isolayte. Some noise generated by an impact is actually airborne noise - the clip clop of high heels is a good example. For this problem an excellent Maxi 60 ceiling below might be the solution.

The decibel (dB) -  the unit used the quantify the energy or pressure of sound levels. dB’s are used to measure many different parameters and care should be taken to ensure that any performance referenced or quoted relates to an appropriate measurement.  The human ear has a range of sensitivity between 0dB and around 120dB though prolonged exposure to more than 80dB is not to be recommended. The human ear is not calibrated in decibels though, so if you have a noise problem please don’t get too distracted with different measurements in decibels. If you can hear a noise problem, then it’s a problem.

Frequency (Hertz, Hz) - sometimes referred to as the pitch of a particular sound, the human ear is sensitive to a range between around 20Hz to 20,000kHz. The human ear doesn’t have a linear response to frequency (see A weighting) but this is the range that we are primarily interested in. Typically low frequency noise is harder to reduce than high frequency noise.

A-Weighting, dB(A) – A weighting curve applied to noise measurements to make them more representative of the response of the human ear, (i.e. not as sensitive to very low or very high frequencies but very acute at frequencies between 500 to 4kHz). Frequently seen on noise ratings for fridges and other white goods but also on measurements of noise levels.

Flanking noise – An overused term that essentially translates to a ‘leak’ or an unforeseen problem. Good specification, design and installation should avoid flanking before it ever happens but when it does it is crucial to understand the problem rather than throw more material and time at it. SRS are qualified and experienced acousticians and can diagnose why there is a problem and suggest effective remedial work.

Floating Floor – A floor surface that has a soft cushioning layer below it to reduce the ‘thud’ of footfall in the rooms below. Products like Acoustilay, Impactafoam or SubPrimo are the quickest ways to install an effective floating floor and may also be able to achieve an appreciable improvement in airborne sound insulation too.

Reverberation Time (s) – The amount of time needed for sound to decay by 60dB, or about a millionth of it’s initial level. Cathedrals and caves have long reverberation times (>4 seconds) which is great for choral music but terrible for speech intelligibility. Sonata acoustic absorbers can quickly reduce reverberation and have been used to great success in schools, village halls and scout huts.

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