Where was I? Oh yes, realistic audio level over distance.
Building upon the applications, the Audio Level over Distance Theory model was implemented into the Max patch. This segment that was created for an earlier experiment has formed most of this Max patch. The experiment was successful and allowed for the Max/MSP patch to not only create a more realistic attenuation model, but to simplify the part of the patch that receives and translates a playable character’s position.
The theory put into practice in this experiment creates a realistic simulation of audio level over distance and will be put into the final Max/MSP created application. An option to switch between the basic version and the theory version of this audio effect will also be implemented, to allow the end-user to compare the differences.
A real world test was completed to demonstrate how audio level over distance typically works within an indoor space. In theory the results should not match with the calculator built-in Max/MSP as they are for free field conditions and other audio properties such as reverberation and standing waves will affect the outcome of the level.
The experiment used 80 dB of white noise (1 metre) as its reference point. The dB SPL of the audio source was measured at each distance increase of a metre. A total of 5 metres was used for this experiment.
As expected, the audio level did not decrease 6 dB every meter. When building the Max/MSP patch, the audio level over distance model will be placed first so that other potential audio level effects (such as reverb) will be added to the signal in a more realistic way.
Although I knew the outcome of the experiment before doing it, I had no proof of the theory not matching with the real world scenario… Now I do.
Below are some images took as part of the experiment.
I’ve got a basic version of audio level working in Max/MSP. Sound decreased the further away from the cube.
One thing I did note was that I was using + (addition) to combine the x and y axis together, which didn’t quite work out how I expected. It would be at its loudest point when directly on an axis than just off to the side of it. I then used the * (multiplication) object and it worked how I thought it would in the first place… You know what? just watch the videos it will make a lot sense than I think I am now.
The first video is using addition and the issue it creates, the second shows how that is fixed by using multiplication instead.
Looking back, it makes complete sense using * instead of +. Now I plan to make it even better, adding in the theory I learnt previously.
As always, here are the downloads to this experiment: