How to write dsp to control Surround sound volume control ?

Anybody know surround sound volume control coefficent ?

how do it yourself?

The parameters are just gain values. Each speaker gets one gain setting. So, if you have 3 speakers, you'll see three parameters in RAM.

The gain values are calculated based on the distance of the speaker from the listener, using the inverse square law.

http://en.wikipedia.org/wiki/Inverse-square_law

You can calculate the gains manually using the inverse square law and then normalizing the gains as you wish.

Here's an example with 6 speakers. You can see that the speakers that are eqidistant from the listener have equal gain settings.

Hi BrettG, thank you very much.

But i still don't know it , can you tell me detail or give me a example ?

Here's a website with some good examples: http://hyperphysics.phy-astr.gsu.edu/hbase/acoustic/invsqs.html

The basic idea is that when the distance doubles, the sound pressure level is divided by 4.

So, let's assume that I have two speakers in my system:

Speaker A is 1 meter from the listener.

Speaker B is 2 meters from the listener.

In order for the listener to perceive that speaker A and speaker B have equal loudness, I have to make speaker B (further away) 4 times louder than speaker A. In another way of thinking, speaker A (closer) has to 1/4 as loud as speaker B.

So, speaker B will be 0 dB, and speaker A will be -12 dB (1/4).

I'm pretty sure that's correct. Somebody please correct me if I'm wrong!