Estimating Exhaust Sound Levels

[vex]

Let me preface this post: I do not know the industry standard for determining exhaust sound levels. This is just an exploration.

I'm looking at redoing my exhaust and would like to have a rough ball park for estimating different configurations. My thought would be to use structural engineering motifs to estimate the sound possibility. In other words base it off an electrical circut diagram. The Voltage in is the unbaffled exhaust level leaving the exhaust ports. Resistors are the mufflers, and Voltage out would be the sound level heard. Doing a direct comparison between voltage in and voltage out will yeild a % decrease, and since we're eliminating piping reverberations and deconstructive interference from there and the different bends we get an upper limit to how much the mufflers will at least muffle.

My question is this: On average how much of a reduction occurs on sound. For instance; given a set db limit and placing a muffler at the source, how much of a db drop will be seen? Is it dependant on frequency or is the major player the db level itself?

If one has the means and wherewithall to do an experiment it would be greatly appreaciated. My design experiment is this:

Take a 100db source. Take different mufflers and measure the sound of the 100db source. See the result.

That result then could be used to do a percentage, so if there was a reduction of 20db it would be 80%. This could then be put into the resistor form so that if there was a 10v application, the resistor would reduce it to 8v, and so on down the line.

Now I know that sound is dependant on a large number of variables; exhaust gas velocity, temperature, pressure, and even materials. But what I am attempting to do is to figure out a simple means for 'eyeballing' the sound level of different exhaust systems.

Thoughts?