When I first started working in acoustics, I heard this phrase “acoustic ABCs”. At the time I didn’t realise that it was a literal acronym for three acoustic terms. So, what are these ABCs?

Essentially, they are used to summarise the three acoustic concepts used to ameliorate problem noise.

Absorb

The A is for Absorb. This is a principle used to reduce reverberation by absorbing (rather than reflecting) sound.

An example of this is where absorptive panels are used in a gymnasium to offset the impact of a basketball game.

Another example is curtains and rugs in a house with polished wooden floors and lots of windows. Both of these soft furnishings absorb sound and stop reverberation.

Block

The B is for Block. This principle is used to stop noise in its tracks! It is often used to improve speech privacy.

For example, adding an office pod can separate the person inside the pod from the noise in the office outside. It acts as a physical block to the noise.

Similarly, installing a physical wall or partition between spaces can improve the acoustics. Even without a full enclosure, partitions of a sufficient height can block some noise. For example in a call centre, higher partitions can block some of the talking noise.

Another example is a box placed over a water pump. With the correct materials this can absorb noise and block noise from escaping.

Cover

The C is for Cover. This principle is used to mask the impact of noise where the A and the B do not work. Or if A and B cannot be used.

An example of the A and B being used but not working is in our case study at a Maternal Child Health Nurse clinic. They had utilised absorptive materials in the ceiling and even on the surfaces within the clinic. They had also used significant blocks including door seals, extra thick plasterboard and other treatments. This had made the space quieter, but did not solve the problem. It required the cover of sound masking to create speech privacy.

An example of where A and B cannot be used is our case study at a warehouse where the aesthetic was particularly important. Adding any absorptive materials or other physical barriers would ruin the expensive fit out. So the C needed to do all of the heavy lifting.

Conclusion

Each of the Acoustic ABCs have their place depending upon the needs of the end users and the space itself.

For more information on sound masking (the “C” of the ABCs), go to www.soundmask.com.au