I am not saying that 9db shows that 10db is 10x the power. The fact is that 10db is 10x the power and that if you follow the example through, you will see that it is not linear.

Also you have to be careful of how you state the question, a 9dB gain is relative to a known amount (in my example I used a reference of 1mW) a 9 dB gain does not necessarily equal 8mW, it is 9db higher that whatever is being referenced.

Just look at my example again, you stated correctly that a 3 db gain doubles the power. So if we reference
1 mW and you add a 3 db gain, you double the power so you now have 2 mW of power. If you add another 3 db of gain, you double the power again, so you are now at 4 mW, add another 3db, double again, power is equal to 8 mW. To take the example further and add another 3 db you end up with 16 mW of power.

Take the same reference (1 mW) and add 10 db this time and you have 10 mW of power, if you add another 10 db, you multiply by 10 again and you have 100 mW of power.

Take a look at the URL from Elistan...it explains it well, if I am not doing a good job.

 

Here's another way to look at it:


db power
0_____1.0000
1_____1.2589
2_____1.5849
3_____1.9953
4_____2.5119
5_____3.1623
6_____3.9811
7_____5.0119
8_____6.3096
9_____7.9433
10____10.0000


It's just that with the way the logarithmic scale works, a 9bd increase is an eight-fold increase in power, and a 10db increase is a ten-fold increase.

 

OK, I understand. It's been 11 or 12 years since I spent quality time with logarithms. I knew that decibel increases weren't linear, but I thought that corresponding power increases would also be nonlinear.

 

The good news is that the crossover has four jumpers for setting 0, -3, -6 and -9dB for the tweeters. It's all starting to come together now. Just... a few... more... tweeks.........