Acoustic FAQs


This blog post comes from Instyle’s website

Why are acoustic products necessary?

Workplaces have opened up by adopting open-plan, collaborative working spaces, while bars and restaurants have incorporated hard, sound-reverberating surfaces. Both of these trends have resulted in increased noise and disruption, driving the demand for sound absorbing materials.

Sound absorptive acoustic products are necessary to control reverberated noise in building interiors to allow occupants to communicate clearly and be comfortable in an interior environment. Poor acoustics can negatively affect productivity, mood, health and enjoyment of being in a space.

 

What is acoustic comfort?

Noise within a room consists of direct sound (from the sound source) and reverberant sound (reflected from the walls, floor, windows and ceiling). The acoustic performance of a room is determined by the proportions of reflective (reverberant) and absorptive surfaces.

The acoustic comfort of a room varies according to the sound absorption, reflection and diffusion of its wall, ceiling and floor surfaces as well as other objects including hard and soft furnishings. The higher the absorption and diffusion levels the more reverberation is controlled. When there is too-much sound reverberation, it becomes difficult to follow speech or reproduce high-quality sound, and irritating noise sources are heightened. Sound absorptive treatment is therefore essential in public halls, meeting rooms, workplaces, theatres, educational institutions, healthcare and industrial premises. Non-amplified spaces such as courtrooms, recital and orchestral venues require high levels of sound diffusion or sound scattering to maintain clarity without reducing the volume of the sound produced.

Extreme acoustic environments have a negative effect on people, it is not natural for humans to be in dead, overly-absorptive spaces or reverberant noisy spaces. Humans function and feel their best where there is a good balance of reflection and absorption in a space.

Will two different products with the same NRC perform in the same way?

When comparing the acoustic performance of competing products with an equivalent NRC value, ensure you are comparing ‘apples with apples’. Check that the test method and conditions (direct fix or airgap depth) are the same and that no other absorptive materials have been used during testing. For example, a wall carpet supplier quoted an NRC rating of 0.8, however this rating was achieved while the product was installed over bulky fiberglass insulation, which acts as the sound absorber. Without the acoustic insulation material behind, the wall carpet achieved an NRC of 0.2.

Additionally, the products can vary in the level of absorption of the relevant frequencies that need to be targeted. As per example below.

What are the human speech range frequencies?

The average fundamental speech range frequencies for people, the sound produced by the human voice, are for men 85-180Hz, women 165-255Hz and children 250-300Hz. These are fundamental averages and do not include speech harmonics that range higher than these fundamentals.

Would acoustic treatments be the same for each room?

There is no one size fits all approach. The acoustic treatments will vary on:

  • Room use: Meeting, classroom, restaurant, office, live venue
  • Room shape: Glass walled, cathedral ceiling, domed, ceiling heights
  • Surfaces: Concrete, carpet, acoustic ceiling tiles, plasterboard, exposed soffit
  • Background noise: HVAC, office equipment, transmitted from other areas
  • Professional advice: Engage an acoustic consultant in the early design phase

For more information on Room Acoustics for specific room types, please refer to our Room Acoustic Guides series.