double power

Post by **bdubs767** » Tue Apr 10, 2007 9:07 pm

what is the db rules?

I always thought it was

double your power = 3db gain = double the spl

but someone told metonight it is....

times 10 your power = 3db gain = double spl

How did I miss this all this time?

Audiophiliac · Post by **Audiophiliac** » Tue Apr 10, 2007 9:54 pm

A doubling of power = 3dB gain. Which is what is normally referred to as the minimum needed to hear an audible increase in volume, although I am sure a lot of people can hear smaller increases.

To double SPL, you need 10 times the power or 10dB increase. Every 10dB is a doubling of SPL or perceived volume. So 100dB is twice the SPL as 90dB.

There are some more scientific and quantitative descriptions available by googling

1moreamp · Post by **1moreamp** » Tue Apr 10, 2007 10:11 pm

Audiophiliac is dead on correct... C

rolandk · Post by **rolandk** » Wed Apr 11, 2007 8:15 am

The dB formula for power is different than dB for SPL (and voltage and current)

For watts its:

dB=10 log (P1/P2)

For SPL/volts/current its:

dB=20 log (P1/P2)

Post by **bdubs767** » Wed Apr 11, 2007 8:22 am

well I missed the bus on this one...

Errin, Fowler, and Paul time to pick me up in the short bus again....

Post by **Bfowler** » Wed Apr 11, 2007 8:26 am

we have to go back and get the special short bus with the wheelchair elevator.

1moreamp · Post by **1moreamp** » Wed Apr 11, 2007 9:07 am

well it all goes back to 10 logs or 20 logs

wheelchair people can't lift logs so you have nothing to worry about