Total energy produced by sound source

[dvderels]

Hello,

I have measurements of the sound intensity produced by a sound source for a given frequency (*). These measurements were taken on on a grid on an imaginary sphere around the source. From these measurements it is clear that the sound intensity is not equal in all directions.

The measurements are calibrated in DB_{SPL}.

The problem: how can I get an estimate of the total energy dissipated by the source?

What I did so far is:
-for each point I calculate the area of the sphere that is covered by the point.
-I convert the DB values into intensity values: I = 10^{DB/10}.
-multiplying the Intensities in each point with the area of covered by the point
-summing all these numbers.
-to get an absolute intensity value, I multiply this number with 10^-12 (the sound pressure level base for calculating Db values).
-This number should give the number of WATTS. This should be multiplied with the duration the sound source is on.

The questions:
-So, is this correct?
-Is there a quick way to calculate the energy dissipated for example using a simple model for a source?

Regards,
Dieter




(*) The source produces more than 1 frequency of course. But let's start off easy.

 

[Bob S]

Go to http://www.sengpielaudio.com/calculator-soundlevel.htm

This is an online calculator relating sound SPL's, Pascals (Newtons per square meter), and watts per square meter.

 

[dvderels]

Go to http://www.sengpielaudio.com/calculator-soundlevel.htm

This is an online calculator relating sound SPL's, Pascals (Newtons per square meter), and watts per square meter.

Thank you for the reply, but I knew about this site.

The problem is that it just gives a way to calculate Intensity ( = W/M² or J/M²S) from Decibel. It does not give a way to calculate Energy (W*Time) for non-uniform distribution of W in space.

So, that does not help me very much to solve my particular problem. But I agree that www.sengpielaudio.com is a top site.

 

[Bob S]

The following site discusses the angular distribution of various sound sources (cardioid etc.)

http://www.mediacollege.com/audio/microphones/directional-characteristics.html

Unless you know the angular distribution you should use the following equation in polar coordinates:

P (pressure) = A + B*cos(theta) where A + B = 1. For a cardioid source A + B + 0.5