"In my experience, I don't think I know of a business that has developed and tested its operable walls with as much knowledge of acoustics and the performance of its products"
Graeme Harding, Fellow of the Australian Acoustical Society

Mutes normal conversation 34-38 Primary Schools
Normal voices may be intelligible 37-41 Church halls, Quite meeting rooms.
Normal voices barely intelligible 40-44 Typical meeting rooms, Schools.
Normal voices unintelligieble 43-47 Boardrooms, Conference centres.
Raised voices barely inteligible 46-49 Hotel functions rooms
Major function noise controlled 46-49 Convention centres
*Assumes peripheral leakage is minimised.

What do you need?

It is impractical to cut out all sound transmission so a good criterion is "To limit transmission to a level that is not longer distracting".

Aim for a sound rating in balance with the acoustics of the surrounding structure. Even with a perfect operable wall, sound will still seep through ceilings, carpets, aircon, ducts, etc.

Controlling this peripheral leakage around the operable wall (for example with baffling above ceiling) will do a lot to improve the overall performance of the installation.

Similar activities require less sound isolation than a quiet activity next to a noisy one. Amplified sound is more difficult to suppress. General background noise helps reduce distraction.

Avoid specifying far high ratings than needed. High STC operable walls are costly. See "Laboratory vs. Real Life"

Myths, Lies & Decibels!

Don't get hung up over one or two STC's. Some manufacturers play numbers game "Mine is 1 STC more than yours!". The human ear can't discern a 2 STC difference, and even laboratory results can vary by 1 STC depending on the conditions.

Beware of U.S. results. They can be 10% higher than tougher Australian testing. Also be aware that STC is a more stringent measurement than simple, speech frequency averages.

Ensure test results are reasonably recent and are from reputable laboratories like RMIT or CSIRO. Laboratories with non-standard testing protocols do exist both in Australia and overseas.

Thin light panels are unlikely to be as effective as thicker panels. There is no magic to acoustic performance and weight is a key factor. Check the test reports to be certain.

Our Testing

It's very good and it's been done recently at the RMIT, one of the Australia's leading laboratories.

All tests have used sweep seals alone at the top and bottom panels, even for the highest STC test (demonstrating it is not necessary to adopt retractable seals to achieve the sound rating required.)

Spacial Concepts offer 36 STC through to 52 STC. Our ratings are about the highest achieved in Australian tests.

Laboratory vs. Real Life

Acousticians measure the performance of an operable wall in laboratories (LAB STC). In real life even a perfectly installed wall is unlikely to perform as well due to the deficiencies of the building. Buildings inevitably have peripheral leakage through airconditioning ducts, carpets, ceiling tiles, etc. which can reduce the field STC by 10%-15% below the LAB STC. Be aware of this when specifying. In critical situations specify both a LAB STC and a required FIELD STC or Noise Isolation Class (NIC). Please contact Spacial Concepts if you need advice on this.