My name is Ludvig and I’m a programmer and a sound designer on this game.

Like most people working within the games industry I know that most indie teams don’t have the time or manpower to have one person focusing solely on the sound in the game and this usually results in the sound of a game becoming more like an afterthought rather than a vital priority, the goal of my devlog is to help YOU and your team get a better sound design with small means.

In this devblog I’ll start with a simple trick to get the change in distance of a sound to feel more authentic. Most think of this as a linear dropoff (i.e. if the sound is 10 times further away it should be 10 times quieter than at the original position/volume).

In reality the dropoff is exponential, following the Inverse Square Law. Since sound travels outward in all directions doubling the distance will result in the sound not only doubling horizontally, but vertically as well this means that doubling the distance will result in the intensity of the sound being only ¼ of its original intensity.
In other words, if you are next to a speaker playing at 100 dB of sound intensity, merely doubling the distance that you are to the speaker will drop that intensity to 25 dB. If the radius triples, the intensity will be 1/9; etc.

Now we know how the distance effects a sound but what about the different parts of a sound (the frequency spectrum). Due to dissipation, distance also changes the frequency spectrum of a sound.
High frequencies are attenuated more strongly by air than low frequencies. This is due to differences in friction losses (dissipation) over the frequency spectrum. Deeper frequencies therefore travel much longer distances because they are absorbed less by the air. Just think of the difference between a dull, low thunder roll from far away and a thunderstorm raging overhead.

Knowing all of this we can now more accurate represent the change in distance of our sound.
As seen before we have two variables to work with, exponential drop off and frequency spectrum, We do not need to perfectly replicate this exactly as they are in reality, but if we have these in mind we can create better sound.

So how do we apply this to our game? We can start by discussing how much of each variable we want to use, and by realizing that the most authentic sound doesn’t always mean the most enjoyable experience. By doing this we can craft a mix that fits our game and desire.
Personally, I use Wwise for this but you can use any other plugin that gives you the ability to affect the sound in this way. To make my sound I use an EQ calibrated to the dissipation of sound up to 50 meters away(the approximate max distance of any sound in our game) and an volume change based on the Inverse Square Law, both of these effects are created in Wwise and Unity.

Next time I’ll talk more about the ways we can improve our sound.
Sincerely Ludvig H.