FAQ

How is sound absorption measured?

Measuring Absorption

Absorption can be measured in two ways:
Method 1: In a “standing wave tube” or “impedance tube”. This is a cheap method, for which a small piece of material is needed.
Method 2: In a “reverberation chamber”. A bigger piece of material is need for this method. The measurements take place in a bigger laboratory. Method 1 only measures the perpendicular incidence of sound. This method measures the absorption of all angles at the same time. Contact these companies for help with measuring your acoustics.

 

To use data in building acoustics it is better to use the measurement results of a reverberation chamber. These are more representative for use in real situations. However, the tube method is simpler. When nothing else is available, this data is fine for use.

 

When measured in a reverberation chamber, the absorption coefficient of some materials are higher than with the tube method. This is due to the bending effects and to the edges of the materials which are placed in the reverberation chamber. Because of the effects of the material, higher values than 1.0 can be measured in the reverberation chamber. The vertical sides of the material also absorbs sound. This is not corrected in the accepted measurement method.

 


Sabin

It is better to round down the value to 1.0 instead of using a value higher than 1.0. However, most measurement institutes don’t do this.

Het is dan beter de waarde af te ronden op 1.0 in plaats van een waarde groter dan 1 te gebruiken. De meeste meetinstituten doen dit echter niet. Absorption of sound is measured in (metric) sabin or in square meters (and in the USA in square feet). In the case of a room with chairs, one can calculate per chair:

Frequency	250Hz	1 KHz	4 kHz
Chair (uncovered)	0,018	0,036	0,028
Chair (covered)	0,26	0,46	0,41
Chair (occupied)	0,40	0,65	0,46

 

The sound absorption for (standing) people in a room in Sabin (please note, the data below are in m2 per person):

 

Frequency in Hz	125	250	500	1000	2000	4000
General people (avg)	0,19	0,28	0,37	0,46	0,46	0,37
Adults	0,23	0,33	0,39	0,43	0,46	0,47
Young children	0,17	0,21	0,26	0,30	0,33	0,33
Teenagers	0,20	0,28	0,35	0,39	0,42	0,42


From this number, one has to subtract the absorption of the floorspace which is occupied by people. Speaking voices are generally between 1000 and 1200 Hrz.

How much acoustic material do I need for my room?

Every room is unique. Good acoustics depend on several characteristics of the room, such as hard or soft materials on the floor and leather or fabric covered furniture. The acoustics get worse when there are more hard materials in the room.

 

Over the years, we've noticed that there's a rule of thumb for all of our acoustic assignments and solutions:

 

1/3 of your room's square footage should be occupied with acoustic materials to create an optimal acoustic environment.

 

A room of 49 x 23 feet is 1130 square feet and 1/3 of this is 377 square feet. This means that 377 square feet of acoustic art or about 6 acoustic vases are needed for optimal sound.


It's also possible to use an iPhone application to measure the decibels in a room. Click here to download the application.

 

Urban Myths

There are several urban myths to dispel around the effects of acoustics.  For example:

 

1. Sticking egg cartons under tables only affects the sounds your shoes make. And also, it can be a nice game for children to play with under the table.

 

2. Curtains do have an acoustic absorption, but when they are gathered to the side, their acoustic value is small.

What acoustic solutions do we offer?

The Acoustic Factory offers beautiful solutions for creating amazing acoustics. We have recently developed a "cradle to cradle" product with our acoustic moss panels.

 

Almost all of the products from the Acoustic Factory are custom designed and developed by us for you. The overview below gives you more information about which product might be best for you.

 

Of course, we are happy to provide custom advice. Contact Mr. Acoustic for a consultation.

 

Acoustic  art

Beautiful art with an absorbing look!
More information

 

Acoustic blankets

Blankets of melamine foam are used as the base for many of our acoustic solutions
More information




Acoustic lampshades

Acoustic lampshades with their own unique personalities.
More information

 

Acoustic wall panels

A beautiful photo or illustration with acoustic functionality that can be made in any size.
More information

 

Acoustic tubes

Tubes made from melamine foam that come in a variety of sizes.
More information




Acoustic wallpaper

The perfect picture on your wall which creates an absorbing surface. 
More information




Acoustic desk dividers

Acoustic desk dividers that create a peaceful environment with an extraordinary view of your choice.
More information

 

Acoustic lamp “Mr Silence XXL”

A beautiful lamp with strong acoustic functionality. This lamp is approximately 8800 cubic foot and creates amazing lighting using LEDs. 
More information

 

Greenwalls

A beautifully natural acoustic solution. Bring nature indoors, and enjoy!
More information

 

Acoustic vases

Acoustic solutions disguised as a vase or planter.  It's a favorite plant, good acoustics, and a beautiful accessory all in one!
More information

How do I calculate my acoustics?

We will gladly help you find the best solution for your acoustic problem. To give you an idea of what you will need, here are a few things to think about:





1. Solve the problem at the source of the sound.

For example, if there are four desks in an office, it’s advisable to solve the acoustic problem near the desks. In this case, acoustic artwork is less effective than acoustic desk dividers.





2. Everything in a room has an effect on the acoustics.

Glass, concrete, wood, and melamine foam are all acoustic materials. For example, concrete has an NRC value of 0.01 and melamine foam has a value of 1.0. This means that melamine foam absorbs more sound and doesn’t reflect as much as concrete does.

 

We often get questions of whether curtains and rugs absorb sound. The answer is they do. However, it is better to find a solution near the source. The solution should be as unnoticeable as possible, or customized as an art object.





3. What kind of sound do you want to dampen?

Most of our products are designed to dampen speaking voices, which are generally between 1000 and 1200 Hrz. We also offer many solutions that dampen other frequencies. 

 

Over the years, we've noticed that there's a rule of thumb for all of our acoustic assignments and solutions:

 

1/3 of your room's square footage should be occupied with acoustic materials to create an optimal acoustic environment.

 

A room of 49 x 23 feet is 1130 square feet and 1/3 of this is 377 square feet. This means that 377 square feet of acoustic art or about 6 acoustic vases are needed for optimal sound.

 

For solution advice, or help with measurements, we are happy to assess your situation and create a custom proposal.

What is acoustics?

Acoustics

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. The application of acoustics can be seen in almost all aspects of modern society with the most obvious being the audio and noise control industries.

Acoustics are also the influence that sound and resonance has on a room. For example, you've probably heard the phrase "this room has bad acoustics". It mwans that the properties of the room do not match the usage.  For example, a concert hall has very different requirements than a lecture room.




Reverberation

Reverberation is the persistence of sound in a particular space after the original sound is removed. A reverberation, or reverb, is created when a sound is produced in an enclosed space causing a large number of echoes to build up and then slowly decay as the sound is absorbed by the walls and air. This is most noticeable when the sound source stops but the reflections continue, decreasing in amplitude, until they can no longer be heard. As time passes, the volume of the many echoes is reduced until the echoes cannot be heard at all.

 

Sound absorption

Sound absorption is that property of any material that changes the acoustic energy of sound waves into another form, often heat, which it to some extent retains, as opposed to that sound energy that material reflects or conducts. Acoustic absorption is represented by the symbol A in calculations. Absorption is not a single mechanism of sound attenuation: propagation through a heterogeneous system is affected by scattering as well.

 

The absorptive of a given material is frequency-dependent and is affected by size, shape, location and the mounting method used. Porous insulative materials such as mineral wool or glass wool are effective sound absorbers compared with good conductors such as metals.

 

Source = Wikipedia 2012