Limiter Settings for protecting drivers

[cforger]

Okay, to make sure I don't toast my new HL10a driver in my Tuba 24, I want to make sure I set my limiter on my Driverack 260 correctly.

Here's my logic:

HL10a is a 300w RMS unit @ 8 ohms. I've read that some people believe it doesn't hit power compression until 400w in a T24.

I have a Mackie FR2600 driving this right now, which dumps 500w per channel at 8ohm.

Max input level on the Mackie is +22 dBu.

Soo.. if I assume that 22 dBu creates 500w into a 8 ohm load, then I can assume 22.73w are being created for every 1 dBu. Therefore, if I wanted to keep the HL10a at 300w of power, I need to set my limiter to 13 dBu (13x22.73=~300).

So my first question is if this logic/math is correct.

My second question is if limiting to 300w is too conservative. The Driverack 260 has a brick wall limiter, plus some compressive features which I can use to make overshoots very limited or totally brick walled.

While I'm making sure everything is okay I'm limiting to 200w which is still a whole crapload of noise.

I guess I'm trying to find the limits of sound quality, and then the limits of sanity for driving this unit.

Tnx.

[James R]

This is what I got here somewhere,can't find the original post now.
Anybody correct me if I am wrong

Volts = square root of watts x ohms

example: 400 watts x 10 ohms = 40,000 sqare root of = 63.245
( 63 volts )

EDIT:Found the post http://billfitzmaurice.com/phpBB2/viewtopic.php?t=2897

[Bill Fitzmaurice]

The only way to be sure what the amp is doing is to measure the output voltage. Use ohms law as described above to find the safe operating voltage, set the limiter so that with the amp attenators wide open that voltage is not exceeded no matter what you do with the board. Measure with no speaker connected, pink noise as a source.