how is the volume of an audiosource computed?

Questions & Answers
1

I’m working on a serious-game, where we have to do some exact audio measurements.

What I have is an audio file with a reference decibel value. So if I play this audio file with the volume of the audiosource set to 1, I should have an output decibel value of the reference value.

Now I want to reduce the volume by let’s say 20 decibel. How would I do that?
My guess was doing it with the formula:

volume = referenceValue / wantedDecibel

I got the following result (software value / measured millivolt / measured decibel):

values

Does anyone know what exactly the formula behind the volume 0…1 of an audiosource is? and how I could convert it to decibel values if I know the maximum decibel value of the soundfile?

I would appreciate if you comment any thoughts and guesses on the matter :slight_smile:

thanks & cheers

2

Well if you use 2D sound then the volume is going to be linear interpolation 1 being your total file db and 0 being no sound.

If you have a sound of 120db and you wand it to play at a exact 70db you’ll use:
(wanted_Db/Total_DC) (70/120) as volume 0.58333.

That said, you’ll have to measure your speakers output to be the same as the audio file (At the listener position).May be there you should use a db measurement tool.If you don’t you’ll have to calculate not only the good voltage for speakers but also the inverse square decay law…

At that point i would prefer headphones.

I wish it helps. good luck