Basics on Acoustics

Let’s take a look at what sound does inside your room.

What is acoustics? It is a science, governed by the laws of physics, that helps us understand and predict the way that sound behaves in an environment. A space is said to have good acoustics if it provides the sound environment conducive to the way we want to use it.

Low frequency sounds tend to spread out and permeate the room. When the wavelength of a sound is the same as a room dimension a room mode will occur (when the volume is high enough to excite it)…and this will happen when you play or listen to your music.

This is due to the natural resonance of the room itself. These effects are called “Room Modes.”

There are 3 types of room modes, Axial, Tangential and Oblique.

Axial Modes

Axial modes are based on the length, width and height of your room.

Tangential Modes

Tangential modes are based on the dimensions of 4 room surfaces.

Oblique Modes

Oblique modes are based on the dimensions of all 6 room surfaces.


Room modes create a series of peaks and dips throughout the room, areas where the volume is actually higher or lower than that coming out of the speakers. The sound pressure caused by room modes is greater at walls, greater yet at dihedral corners (where walls meet walls – ceilings and floors) and greatest yet at trihedral corners (wall/wall/ceilings or walls/walls/floors).

Obviously if you are mixing and happen to be sitting in an area where there is a dip – you will add more bass to the mix to get it to sound right to your ears, but when you play it back outside of your mixing room you will find the mix to be bottom heavy – too muddy with bass.

By the same token – if you mix where there is a peak – you will add less bass (to balance things out) and find the mix to be light in the bottom end (too thin) when you listen to your recording outside of your room.

In order to fix things, so you can create a mix that translates well into other environments, you either have to treat your room to lessen the effect that these room modes have in your listening environment, or, you have to learn what your room is doing so your mixes translate well in the real world.

Yes – you can learn to compensate – but it isn’t fun – it’s a lot of hard work, and if you are doing this with enjoyment being a part of the equation – you’ll be much better off if you fix your room.

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