Acoustics
acous·tics |ə-ˈküs-tiks
A science that deals with the production, control, transmission, reception, and effects of sound…
Sound Absorption vs. Sound Proofing
Sound proofing prevents noise from passing through a space by blocking it from entering or leaving. Sound absorption improves a room’s overall acoustics by taking in sound instead of reflecting it, reducing echo in the process. If you are looking to control sound within a space, it can only be absorbed or diffused, and not blocked.
It is important to note that our products only absorb sound – they do not block or eliminate it. The noise will still be there, it just won’t be as intense or unpleasant as before.
Sound Waves
After leaving its initial source, a sound wave travels until the energy propelling it is diffused, absorbed or fades.
Sound cannot be absorbed unless a material, structure or object is present to take in and hold the energy. This is why noise in spaces without carpets, curtains, acoustic ceiling tiles or even upholstered furniture, can often be so severe and unbearable. The repeatedly reflecting sound waves ricochet and echo around the hard surfaces of the space with nowhere to escape. The noise can only fade over time.
Sound Wave Analogy
Have you ever used your hand to send a loose pool ball into a pool table’s pocket? Think of the ball as a sound wave. When propelled towards a pocket, it either lands in the pocket and is absorbed, or the ball misses the pocket and bounces off of the table bumpers to be launched in a new direction. The ball will continue to bounce off the bumpers of the table until its forward motion has decayed, and it stops, or its journey ends in a pocket.
Simply think of Chatterbox acoustic artwork as the sound “pockets” you need to capture rogue sound waves within your space. The more coverage, or pockets, you have, the more sound you will capture.
Acoustic Terms
The science of acoustics can be intricate and complicated. Below are some common acoustic terms and simplified definitions.
Please, contact us if you would like further information or have any questions.
Acoustics
A science that deals with the production, control, transmission, reception and effects of sound, or, the qualities that determine the ability of an enclosure, such as an auditorium, to reflect sound waves in such a way as to produce distinct hearing.
Airborne Noise
Any sound that is transmitted through the air like music or speech. The noise created from your neighbor’s dog is airborne noise.
Decibel (dB)
A unit of measure for sound levels, widely used in electronics, signals and communication. Below are examples of various decibel levels:
- 10 dB: normal breathing
- 20 dB: whispering from five feet away
- 30 dB: whispering nearby
- 40 dB: quiet library sounds
- 50 dB: refrigerator
- 60 dB: electric toothbrush
- 70 dB: washing machine
- 80 dB: alarm clock
- 90 dB: subway train
- 100 dB: factory machinery
- 110 dB: car horn
- 120 dB: ambulance siren
Direct Sound
Sound waves that reach the listener’s ear directly from the sound source. These waves reach the listener’s ears first in most acoustic environments.
Echo
Often increased in cavernous spaces, a sound, or series of sounds, caused by the reflection of sound waves off of hard surfaces back to the listener.
Flanking Sound
Sound that transmits between spaces indirectly, going over or around a separating element, such as a wall, rather than through it. Hearing others in a next room through air ducts is an example of flanking sound.
Flutter Echo
A series of rapid, repeated reflections caused by sound waves bouncing between parallel reflective surfaces. The sound waves reach the listener at alternating moments producing a fluttering sound.
Frequency
The number of sound waves that pass a fixed place in a given amount of time and measured by the hertz (Hz). Frequency and pitch are generally tied together. The higher the frequency of a sound wave, the higher the pitch of the sound we hear. In reverse, the lower the sound we hear, the lower the frequency of the sound wave.
Hertz (Hz)
The derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named after Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.
Impact Noise
Impact noise is a form of structure borne sound that occurs when an object impacts on another, resulting in the generation and transmission of sound. The structural vibration caused by the impact results in sound being radiated from an adjacent vibrating surface.
NRC Rating
Noise Reduction Coefficient ratings measure frequencies between 250 – 2,000 hertz (Hz) and are used to rate the effectiveness of acoustic products. The density and thickness of the item will affect the rating. Typical ratings range between 0 to 1, however, formulas used to determine NRC sometimes allow for a value greater than 1.
An NRC of 0 means the item absorbs no sound and is completely reflective, whereas a rating of 1 means the item absorbs all sound. An NRC of .85 means that 85% of all sound is absorbed by the item with the remaining 15% of sound reflecting back throughout the environment.
NRC 0.00 to NRC 0.20 = Minimal Absorption
NRC 0.30 to NRC 0.55 = Low Absorption
NRC 0.65 to NRC 0.85 = Mid-Level Absorption
NRC 0.95+ = Maximum Absorption
Pitch
The quality of a sound governed by the rate of vibrations producing it. The degree of highness, or lowness, of a tone.
Reflected Sound
When a sound wave strikes a surface such as a floor, wall or ceiling, its direction of travel is changed if not absorbed.
Reverberation
The continuation of sound after its source has stopped making it due to the multiple reflections of that sound within a closed spaced. Reverberation reduces when reflected sounds hit absorptive surfaces, such as Chatterbox artwork.
Reverberation Time
The time required for sound to “fade away” or decay by 60 decibels in a closed space. Reverberation times vary depending on the size of the room. For example, an average classroom has a reverberation time of less than 1 second, where a medium sized auditorium has a time of around 2 seconds.
Sound Absorption
Instead of being reflected, the process by which sound waves are taken in, or absorbed, by a material, structure or object when encountered.
Sound Diffusion
The process by which sound waves are redistributed within a closed space by a material, structure or object with the goal of improving sound quality.
Soundproofing
To make a room or building resistant to the passage of sound by attempting to block it from entering or leaving.
Structure Borne Noise
Occurs from the physical impact of an object on a component of a building, such as the floor or a column.