Acoustics FAQ
7 questions answered by NSW's only Bona Premier Dealer.
Acoustics (7)
What types of noise does acoustic underlay control in apartments?
Two main types of noise. High-frequency stuff like music, voices, and TV -- that's controlled by the mass of the floor system. Low-frequency vibrations like footfall and subwoofers -- that's where acoustic underlays and isolation come in. Sound is measured in decibels, and most people notice a 3dB change. A professional floor sander installs flooring systems that meet building acoustic requirements.
What is the NCC acoustic requirement for floors between apartments?
The National Construction Code says the Weighted Standardised Impact Sound Pressure Level (LnTw) can't exceed 62dB for floors separating dwellings. But individual strata buildings often impose stricter by-laws, and some councils push for LnTw of 40-50dB. Make sure your installation meets whatever applies to your building.
Does concrete slab thickness affect floor acoustics?
Yes. Slab thickness makes a big difference -- the gap between a 175mm and 150mm slab can be as much as 10dB. Thicker slabs give you better sound insulation as a base for timber flooring. A professional floor sander takes slab thickness into account when recommending acoustic underlay systems.
What is flanking noise in timber flooring installations?
Flanking noise is when sound travels through the walls rather than through the floor, bypassing your acoustic underlay completely. That's why perimeter isolation is essential -- the floor can't touch walls or fixed structures directly. A professional floor sander makes sure perimeter isolation is done properly in every acoustic installation.
Do thin laminates or thick hardwoods perform better over acoustic underlay?
Surprisingly, thin flexible laminates actually perform better than thick hardwood floors over acoustic underlay. They conform more effectively to the resilient layer underneath. And acoustic underlay materials vary a lot in performance even when they look similar in thickness. A professional floor sander picks the right combination of flooring and underlay for the best acoustic result.
What impact does the 10dB acoustic reduction rule have on flooring choices?
A 10dB reduction sounds roughly half as loud to your ear, and acoustic underlay systems typically give you 10-20dB of noise reduction. So the right underlay can make a timber floor sound half to a quarter as loud as the bare slab underneath. A professional floor sander can help you pick the acoustic system that hits the noise reduction your building needs.
What is the minimum 3dB change threshold for acoustic perception?
Most people can pick up a 3dB change in sound level -- that's the smallest difference you'll typically notice. So if an acoustic improvement is less than 3dB, you're probably not going to hear the difference. A professional floor sander makes sure any acoustic underlay selection achieves meaningful reductions well above that perception threshold.
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