How to combine multiple audio volume setting into one

Question

I have a audio system where I want to be able to control the playback volume of sound effects, music, dialouge etc.

Currently my set up has three Volume settings [0-1].

• The playback volume specified when the audio begins playing.
• The asset's volume.
• A volume from the settigns menu.

I'm currently combinign them simply as playbackVolume * assetVolume * globalVolume, but this gives me a pretty steep volume curve near lower numbers.

Is there a standard way of combining multiple volume controls.

I would rather not use an Audio Mixer for this as we have a custom audio system.

Answer 1

Is there a standard way of combining multiple volume controls.

The multiplication of several "volume" coefficients is a good place to start; It makes the most sense to multiply these floats because they represent a linear coefficient for something. But you should know that these coefficients are not directly representing loudness, they are coefficients for the energy/voltage level in the sound device.

this gives me a pretty steep volume curve near lower numbers.

The loudness of a sound (what we perceive) has a non-linear relationship to the energy (voltage) used to make the sound. When you pass 0.5 to the sound card it will create a sound at 50% of its max voltage, but that will not be half as loud as 1.0 and 100% voltage. The actual relationship from energy to loudness is rather complicated but most software approximates it with a formula like loudness = log10(volume) or loudness = sqrt(energy).

You should be choosing the playbackVolume and assetVolume with this non-linear relationship in mind:

• If playbackVolume scales with distance from the player you need to consider whether the "energy" of the sound drops off linearly or non-linearly with distance.
• If assetVolume is predetermined and you want a specific asset to sound twice as loud as something else you'll need to review your volume numbers in "loudness" terms.
• When you provide a slider in your settings UI for the user to adjust your globalVolume it should be a non-linear slider too. Use a formula like globalVolume = sliderValue^2.

Hopefully after addressing all of these considerations the simple product of your volume floats becomes a lot more usable and starts sounding correct.