Here’s How You Make Sound Decisions on Acoustics

Pun obviously intended. The effects of sound in some industries has an important effect on the quality of work produced as well as in some key applications, especially in the field of broadcast that I currently work in. Sound is the perceived pressure produced by the propagation of energy through a medium released when matter vibrates, while acoustics is the branch of physics that deals with the production, control, transmission, reception, and effects of sound.

Some of the areas of application that are dependent on sound are full/hemi anechoic chambers, radio and television studios, airports, nightclubs, torture chambers (just a guess, I’m not completely sure about this one), recording booths and many more. These are environments where sound needs to be well controlled. An example that I’ve dealt with was in radio studios. Imagine listening to your favorite radio show in the morning then you faintly hear the buzz of a helicopter or the bark of a dog within the show. Such interference would obviously dampen your experience of the show. So before you give them a bad rating, get to know what they should’ve done.

 

 

Soundproofing and Isolation

Soundproofing is the act of minimizing the entry of external noise into a room. Noise comes from many areas; outside noise from traffic, planes; from inside the building like chatter, walking and movement. Noise is captured by sensitive microphones typically used in these applications. It’s obvious measures have to be taken to mitigate the effects of noise in a lab or studio, since running tests or shows only at 3am, dead in the night, is not much of an option. Therefore, soundproofing isolates an area from effects of such noise

For proper isolation, consider right from the very architectural plan of these rooms to cater for factors such as sound pressure, to ensure desired noise levels. The room should be ‘shielded’ from outside noise sources using several ways:

1. Construction with heavy material such as thick concrete walls
2. Use of double doors
3. Heavy doors
4. Closing off the studios from sources of noise within the building such as steps, chatter
5. Sealing any and all air gaps on windows and doors

 

Acoustic Treatment

Acoustic treatment refers to measures taken to ensure good quality sound capture/recording within a room. In-room noise from echo, air conditioning systems and computer fans lead to poor sound capture and this can never be reduced through isolation as discussed earlier. Treating a room requires knowledge of the kind of sound to be captured but a few methods that we will discuss will greatly improve the sound quality compared to no treatment at all.

When we’re discussing acoustic treatment, we refer to catering for the following scenarios:

1. Reflection of low frequency sound off the room walls caused by the size and dimensions of the room.
2. Reflection of mid to high frequency sound off hard surfaces within the room.

To have the best sound, an investment in acoustic treatment material that absorbs and diffuses sound MUST be made.

 

Sound absorption

Sound that bounces off surfaces can be reduced by placing panels which absorb the sound before it reflects back to the capturing devices. You can easily check the acoustic properties of your room by walking to every point of the room and clapping your hands as loudly as you can. Check the reverberations that are produced, if you get audible echoes especially with a ringing sound, you need a great deal of treatment, if you have minimal reverberation, this is good though you still stand a chance to benefit from some acoustical treatment.

The room can be treated using some of the following methods:

1. Using bass traps to absorb low frequencies
2. Using acoustic panels and foam boards to absorb the mid to high frequencies
3. Using diffusers to scatter the other frequencies
4. Use an acoustic carpet specially made to absorb sound
5. In an-echoic chambers, use of large acoustic absorbers

 

Such items could be found locally in Nairobi, like acoustic carpets are easily found at Tile & Carpet Center and other vendors of these products.

Final considerations you could make are the equipment to be used in the room, like computers whose fans make noise, the air conditioning system may also bring in undesired noise. However, different people may want different noise levels in a room so plan and execute wisely with proper research and consult the experts.

Fun fact: Microsoft broke the world record for constructing the quietest place ever and they have an interactive website to show you how they did it, sounds really interesting.