This is a summary of an article originally published on our blog about studio design, room modes and room acoustics.
Introduction
In this article you will learn:
- What are room modes and standing waves?
- What is the Golden Ratio of room dimensions?
- How best to predict the effect of room modes
- What can we do about room modes?
Standing waves
When the room dimensions are proportional to the wavelength (or in fact, half a wavelength), then the reflected sound wave will be somewhat in sync with the original sound wave, and this is where we get extreme peaks and troughs in fixed locations. These waves are known as standing waves, and these cause room modes — a broader term referring to the relationship between the room and the standing waves.
The modal frequencies are related to the room dimensions.
Each and every room will experience a modes to some degree.
Modes are generally a problem associated with smaller rooms, and at frequencies up to 300 Hz.
What can we do about room modes? And what if you can’t change your room dimensions?
Providing targeted absorption at low frequencies will reduce the effect of room modes.
Summary
- ‘Boomy’, ‘dead’ or ‘ringing’ bass notes are caused by room modes.
- Standing waves and room modes occur at frequencies whose wavelengths are proportional to the room dimensions.
- All rooms experience modes, and there is no single Golden Ratio.
- Room modes are generally only problematic in small rooms, and at low frequencies up to 300 Hz.
- To reduce the effect of modes, we can introduce low-frequency absorbers (bass traps) into the space.
Find out more about our work as expert acoustic consultants, designers and engineers.
Suitable suppliers of room acoustic treatments include GIK Acoustics and Jocavi.
References
[2] Professor Trevor Cox, Room sizing for studios, University of Salford.
