"LRod" wrote in message
...

As someone else pointed out, it's logarithmic, so your calculation
isn't quite. An easier way to understand it is that 10 dB is actually
10x, and the next 10 is a power of 10 (10^2=100). So what you have is
20dB is x100, the next 3dB doubles that to 200, and the 1dB left over
is a fraction of x2, so around 220 or so is the decimal equivalent of
24dB.

It's those stray dB between 9 and 10 that messes your calculation up.
9 dB is 8x, but 10 dB is 10x.

Now you had to go and analyze it and make me go check the math. Darn I hate
it when that happens. You had it right until that very last 1 db. A 1db
increase is a 1.26x increase. (200 * 1.26) = 251+

The formula for db is 10 * log (p1/p2). Its not a pure log function.
There's a 10x factor in there. There's a very cool webpage on this with
actual sound files at http://www.phys.unsw.edu.au/~jw/dB.html.

Bob