The Science of Sound PART II: Sound Control

Aug
22
2017

In architectural acoustics, we are concerned with controlling the amplitude and/or the duration of the sound. In walls and partitions, this is done by controlling sound transmission loss and sound absorption. When sound waves strike a partition, some are reflected from the surface, staying on the same room as the source of the sound. Some are absorbed by the material covering the partition and some are transmitted through to the other side.

SOUND TRANSMISSION LOSS (STL) is the effectiveness of a barrier at preventing sound from transmitting from one side to the other. It is measured in decibels (dB), the same as amplitude. To determine STL, one measures the sound level on the side of the barrier closer to the sound source, the level on the opposite side of the barrier, and the reverberation or absorption of the receiving room. The result is given by the following equation:

SOUND ABSORPTION is the effectiveness of a surface material at preventing the reflection of sound. The more sound absorption, the less echoing will exist. The absorption of a material is measured in Sabines (see explanation below) and is found by the equation:

It is very important to know the difference between a sound barrier and a sound absorber. Typically barriers made of hard, dense material may actually increase the amount of echo in the room, while absorbent batts of insulation allow sound to pass through as if they weren’t there. Generally speaking, you can’t use a barrier to absorb sound and you can’t use an absorber to block sound.

Wallace Clement Sabine (June 13, 1868 – January 10, 1919) was an American physicist who founded the field of architectural acoustics.

The Science of Sound Part VII: Beating Flanking Paths

The first step to beating flanking paths is to look at how all of the elements work together from floor to roof-the partition, the space between the ceiling and the roof, the floor, even HVAC ductwork can help or hinder flanking paths.

The Science of Sound Part VI: Flanking Paths

Shoddy construction, customary construction practices, or poor installation of the partition can all contribute to the leaks, known as flanking paths.

Hufcor Joins ‘Making Room’ Exhibit in D.C.

While Hufcor is well-known for movable wall systems within commercial market segments such as education, office, hospitality and convention centers, the solutions for this exhibit are to promote architectural thought expansion for future shifts in demographics and lifestyle changes.