What is Reverberation by Apocalypse Part 2

What is Reverberation? Part Two (Continued from Part One)

You can say,

  • What on earth is reverberation time?
  • How do I treat it.?
  • In a room with high absorption or with few reflections the sound dies immediately or very quickly allowing us to reply.
  • Well what is the time taken for noise to stop after the noise source has ceased, is it measured in milliseconds”

With a relatively dead room (a room with a short reverberation time) the noise (words) created by the spoken sentence become inaudible relatively quickly, allowing the response to be heard and a further question asked, with relatively ease.

However in a live room (a room with a higher reverberation time) this becomes a much more difficult task to carry out. The sound of the previous word over laps the sound of the next word and the sound of the first sentence over laps the sounds within the second sentence and so on and so forth. This means the examples from above would sound more like. (Where capital words express more clearly heard word)


How do i TREAT it? the time for NOISE to Stop…… You get the idea.

It is like having a conversation in a round, like when you sang nursery songs as a child.

However high reverberation time isn’t always a bad thing, if you are Gregorian monk or in a vocal group, a longer reverberation time is desired as it produces a more appealing and warm sound.

This provides a much desired atmosphere to listen or to record in. Producing music in a dead room for this type of activity would really take away from the atmosphere and kill the mood and ambiance trying to be achieved, as the notes world die very quickly and make the sound appear very flat.

As we all know reverberation itself is a perplexed subject which needs more elaborative, more amplified refinement which we can establish and Institute for your complex issues.

For any technicalities call us at +919395333255 or email us at apocalypse@mail.org.


What is Reverberation by Apocalypse Part 1

What is Reverberation???

Reverberation is another name for what most people know and understand as echo. The following analogy explains what reverberation is quite concisely without getting overly technical.

If you press the accelerator pedal of a car, the car accelerates to a certain speed. If the road is smooth and level the speed will remain constant. With a constant force on the accelerator, the engine produces enough horse power to overcome frictional and aerodynamic losses and maintain a steady and even speed, or steady state condition. If you take your foot of the off the accelerator, the car will gradually slow, and come to a stop.

Sound within a room acts similarly to this. When a loudspeaker is turned, it emits noise into the room that quickly grows to a certain level. This level is the steady state or equilibrium point at which the sound energy radiated from the loudspeaker is enough to over come loses in the air and at the room boundaries.

A greater sound energy radiated from the loudspeaker will result in a higher equilibrium level, whereas less energy to the loudspeaker will result in a lower equilibrium level. If you push your foot flat to the floor in the car the equilibrium or speed will be much faster, than those Sunday drivers who only slightly depress the accelerator pedal.

When the loudspeaker is turned off, it takes a finite length of time for the sound level in the room to decay to inaudibility. This means there is an exact amount of time from when the loudspeaker is turned off until the sound from the speaker cannot be heard.

For most environments such as conference rooms, classrooms, sports halls, offices and the typical working environment or public space, the longer the time between the noise source stopping and the noise becoming inaudible, the worse the acoustic environment is perceived. This is because a lot of words and noises overlap one an another.

You can say, ” What on earth is reverberation time? How do I treat it.?

Continued in Part Two of What is Reverberation.

For Further Clarifications Please Call us at +919395333255 or Email us at apocalypse@mail.org

Provision for children having special hearing or communication needs..Acoustic Improvements.

Provision for children having special hearing or communication needs..Acoustic Improvements.

Provision for children having special hearing or communication needs

For the purposes of this document, special hearing or communication needs include, but are not limited to, children with permanent hearing impairment; or with severe or complex needs including:

  • speech, language and communication difficulties;
  • visual impairments;
  • fluctuating hearing impairments caused by conductive hearing loss;
  • attention deficit hyperactivity disorders (ADHD);
  • an auditory processing disorder or difficulty;
  • being on the autistic spectrum.

The Equality Act 2010 places a duty on all schools and Local Authorities to prepare and implement accessibility strategies and plans to increase over time the accessibility of schools for disabled pupils and staff. Schools and Local Authorities are required to provide strategies for:

  1. increasing the extent to which disabled pupils can participate in a school’s curriculum.
  2. improving the physical environment of schools for the purpose of increasing the extent to which disabled pupils are able to take advantage of education and the benefits, facilities and services provided.
  3. improving the delivery to disabled pupils of information that is readily accessible to pupils who are not disabled.

This could mean provision of physical aids and acoustic improvements and aids. These will often benefit both hearing-impaired and other pupils.

When alterations affect the acoustics of a space then improvement of the acoustics to promote better access for children with special needs, including hearing impairments, must be considered.

Approved Document M: 2004 – Access to and use of buildings, in support of the Building Regulations includes requirements for access for children with special needs.

Other guidance includes BS 8300:2009 Design of buildings and their approaches to meet the needs of disabled people.

Code of practice and Acoustics of Schools – A Design Guide.

Extracted from Acoustic Design of Schools Performance Standards.

By Apocalypse Acoustics Inc. For any Clarifications or Technicalities please mail us at apocalypse@mail.org or visit us at http://www.acousticsglobal.com

Acoustic Design of Schools Performance Standards….New-build, conversion and refurbishment work performance Standards.

New-build, conversion and refurbishment work performance Standards.

NEW BUILDING-CONVERSION And REFURBISHMENT: Performance Standards for Acoustics.

The School Premises Regulations and the Independent School Standards apply to refurbishment work, and the acoustic standards for refurbishment works given in this document apply. Where there is a need to upgrade the acoustic performance of an existing building or when refurbishment is undertaken for other reasons, then the building should meet, as far as reasonably practicable, the acoustic performance given in these guidelines to satisfy the School Premises Regulations, the Independent School Standards and the Equality Act.

Although Building Regulations do not apply to all alteration and refurbishment work, it is desirable that such work should consider acoustics and incorporate upgrading of the acoustics as appropriate. In the case of existing buildings, Part E of the Building Regulations applies to material changes of use as defined in Building Regulations. The Tables give values for both new buildings in the columns labelled “new build” and for new elements of a refurbishment in the columns labelled “refurbishment”.

Where there is a material change of use as defined in the Building Regulations, such work shall be carried out as is necessary to ensure that the building complies with the applicable requirements of Requirement E4 of the Building Regulations. In these cases, the ‘refurbishment’ criteria contained within this document apply. The School Premises Regulations and Independent School Standards apply whether or not there is a material change of use.

Extract from  Acoustic Design of Schools performance Standards by Apocalypse Acoustics Inc.

For Any Technicalities or Clarifications mail us at apocalypse@mail.org or visit us at http://www.acousticsglobal.com.


SOUNDPROOFING BY APOCALYPSE ACOUSTICS: Soundproofing is any means of reducing the sound pressure with respect to a specified sound source and receptor. There are several basic approaches to reducing sound: increasing the distance between source and receiver, using noise barriers to reflect or absorb the energy of the sound waves, using damping structures such as sound baffles, or using active anti noise sound generators. TWO DISTINCT SOUNDPROOFING Problems:

  • Two distinct soundproofing problems may need to be considered when designing acoustic treatments – to improve the sound within a room (See anechoic chamber), and reduce sound leakage to/from adjacent rooms or outdoors.
  • Acoustic quieting, noise mitigation, and noise control can be used to limit unwanted noise.
  • Soundproofing can suppress unwanted indirect sound waves such as reflections that cause echoes and resonances that cause reverberation.
  • Soundproofing can reduce the transmission of unwanted direct sound waves from the source to an involuntary listener through the use of distance and intervening objects in the sound path.

For More Information, Solutions and Techniques about Soundproofing or Noise Control, please contact http://www.apocalypseindia.com or Call us at +919395333255. Apocalypse Acoustic Sciences Corp provides complete acoustic design, noise & vibration control for facilities of all types whether it is to support unaided speech or live music or to effectively optimize the acoustical design for speech intelligibility & Musical Acoustics.

Acoustic Panles
Acoustic Panles


Definitions and Background  
What is Noise?  Noise is disagreeable or unwanted sound.  In many instances, noise is a relative definition of a sound since one person’s music may be another person’s noise.  It is difficult to give a very clear definition of an irritating noise.  Generally, noise is an unwanted sound, regardless of its intensity or duration.
Noise Pollution has been recognized as a major threat to human well being.  Much discussion and legislation has evolved in an attempt to recognize and combat the problem of noise pollution.  It has been recognized that noise, of sufficient intensity, can damage hearing and be classified as a hazard.
In combating the problem of noise pollution it is necessary to use a means of measuring noise levels and a system of classification.  The decibel is a number which relates sound intensity or sound pressure.  When most people use the term decibel or discuss noise levels in decibels they are referring to decibels as related to the “A-weighted” scale or, dBA.  The A-weighted scale parallels the sensitivity of the human ear and uses the lowest audible sound that the human ear can detect as the reference point for determining the decibel level of a noise.
The reference intensities used above represent the threshold of audibility where sound is just loud enough to be heard.  At 140 decibels or more acute pain is experienced.  Some common noise values are as follows:

  • Ordinary conversation – 60 dBA.
  • Heavy traffic – 80 dBA.
  • Cocktail Party – 90 dBA.
  • Moving subway train – 100 dBA.
  • Riveting gun – 130 dBA.
  • Hard rock band – 100 to 138 dBA.
  • Jet plane heard at close range – 150 dBA

Any noise rating above 80 dBA produces physiological effects and any long term exposures at much or above 90 or 100 decibels will cause permanent damage to a person’s hearing.  An increase of 10 dBA is a doubling of loudness with respect to the human ear.

Noise generally consists of many tones with varying rates of vibration or frequency.  The frequency expressed in cycles per sound or hertz (HZ) usually is in the range of 20 to 20,000 cycles per second.  The ear is not very responsive to very low or very high tones as it is to the tones of medium frequency.

The dBA scale matches the response of the ear, and is therefore well suited for evaluating noise as it relates to human beings.

For More Information on Noise Control or Noise Mitigation:

Apocalypse Acoustic Sciences Corp

#605, 6th Floor, Vani Nilayam,

Sebastian Road, Secunderabad-3.

Telangana, INDIA.

Ph: +91-40-30621266. Fax: +91-40-27531331.

Email: apocalypse@mail.org.


Reverberation by Apocalypse Acoustics

Reverberation is linked to the speed at which sound energy disappears in a room.

An unfurnished room with hard surfaces, such as a church, is perceived as being more reverberant than a well-furnished living room.

  • The reverberation time is usually defined as the time it takes for sound to decrease by 60 dB.
  • To determine the length of this time, different parts of the reverberation curve are used.
  • When measuring Early Decay Time (EDT), an interval of 10 dB is used. At T20, an interval of 20 dB is used.
  • When determining T20, the evaluation does not start until after the sound level has already fallen by 5 dB.
  • At T30, an interval of 30 dB is used and here, too, the evaluation starts after the sound level has fallen by 5 dB.
  • If the reverberation curve is straight, the EDT, T20 , T30, will all produce the same value. In practice, the reverberation curve is not straight (dashed line), which means that the descriptors will differ.
  • The descriptors T20 and T30 are usually called “late reverberation times” as they measure at the later part of the curve.
  • EDT is called “early reverberation” and is considered to better reflect how we perceive the reverberance in the room.

To understand more about Reverberation, mail us at apocalypse@mail.org or call us at+919395333255. Noel Flemming. Copyright 2015. Apocalypse Acoustics Sciences Corp.


Noise is considered a serious threat to the environmental health. Some of the adverse effects of noise pollution are given below:

  1. It interferes with speech. In the presence of noise we may not able to follow, what the other person is saying.
  2. Noise leads to emotional and behavioral stress. A person may feel disturbed in the presence of loud noise such as produced by heating of drums.
  3. Noise may permanently damage hearing. A sudden loud noise can cause severe damage to the eardrum.
  4. Noise increases the chances of occurrence of diseases such as headache, blood pressure, heart failure, etc.
  5. Noise leads to increased heart beat, constriction of blood vessels and dilation of pupil.
  6. Noise is a problem especially for patients who need rest.
  7. Noise may cause damage to liver, brain and heart.

Noise pollution describes any sound created by people, animals, and machines that disturbs the environment. With these noise pollution facts, you can better understand its causes, health risks, and protection techniques.

We master noise, we do provide end to end solutions, in residential noise, industrial noise, outdoor noise, vehicular noise pollutions, sound pollution, unwanted sound, noise isolation’s, Vibration control, & white noise control solutions.

For Noise Control Solutions and Perfections please mail us at apocalypseglobal@aol.com or visit us at www,acousticsglobal.com

Worship Perfections by Apocalypse

In churches, synagogues and worship centers large or small, words and music can sound incomprehensible to the congregation if sound is not properly controlled.

  • Poor sound quality is common in churches because of an abundance of hard surface materials. Brick, marble, stone, tile, glass, wood and sheet rock are all acoustically reflective.
  • Sound waves bounce back and forth between parallel surfaces, creating a confusion of noise until they finally decay. Even the most strategically-placed speakers and microphones will not compensate for poor acoustics.
    Every room needs some absorptive materials and some reflective materials to get the right acoustic mix for the room’s intended purpose. The challenge is to find that balance.
  • Apocalypse Acoustics Wall Panels and Acoustic Panels from Acube acoustic inc. are designed to absorb airborne sound energy and reduce a room’s overall noise, reverberation and standing waves—creating interiors that reduce the din without sacrificing the divine.

Perfections @Apocalypse Acoustics visit us at http://www.acousticsglobal.com

Fundamentals of Room Acoustics

Most #sound #reinforcement #systems are located indoors, and the acoustical properties of the enclosed space have a profound effect on the system’s requirements and its performance.

Our study begins with a #discussion of #sound #absorption and #reflection, the growth and decay of #sound fields in a room, #reverberation, direct and reverberant sound fields, critical distance, and room constant.

If analyzed in detail, any enclosed space is quite complex acoustically.

For further Simplifications & Perfections in acoustics, we are avaliable@Apocalypse Acoustics.