Help with power handling question...

So I've been running my Herbert (180w) through a 4x12 with Greenbacks (100w) and everything seems fine so far. I have read unofficially that unless you are cranking the amp, it's not producing anywhere near it's rated power spec.

However, a fairly credible source recently told me that even with the amp's volume on minimum, the load is still seeing at least 60% of the amp's power rating. That would mean the Herbert is putting out 108w minimum...but again everything seems fine so far. Am I just getting lucky?

No.

Speakers blow for many reasons but what you're doing is fine. You can blow a speaker with a 10 watt amp just as easily as your 180 watt amp under the right circumstance. With lots of power, you can break the speaker with it being push too hard and it separates the voice coil whereas with too low power, you will heat the coil and fuse it. I have some experience with both types. Power rating and sensitivity are not a standard and the manufacturer sets the parameter by which the speaker is tested.

If you think in terms of a car engine and horse power, a V4 pushed hard or a V8 with power to spare is kind of a similar idea.

Ok I think I'm following you, but I'm still confused about a couple things:

1) is it true that as you turn up an amp's volume, the load will see more watts? If so is there any reasonable way to estimate how much the load is seeing in respect to the amp's volume knob?

2) Even though manufacturers have different standards of testing these parameters, it seems like most people still adhere to the protocol of never overpowering your load (as I am doing, I just thought I would be safe as long as I'm not cranking the amp)

Thanks for the help!

I am not a speaker expert (really I should just keep my mouth shut...) but I personally don't over power more than 20%. I read that somewhere and have always stuck to it.

I have read that the British made celestions are a little more robust than the newer ones (i have almost all British celestions). I have also heard that celestion specs out more conservatively than some other brands.

But the thing is as Markedman was saying is truth. There are different ways a speaker can fail.

I have a hard time recommending pushing 180 watts into handling capability of only 100 watts. Regardless of volume. I would not do it myself, so I can't say go for it.

Think of it like a motor, you can throw a rod, or crack a piston. Either way the motor is screwed.

Thanks for the input. I got a pretty helpful reply from TGP forums:

"G12M25 generate ~97dB with 1 watt. So when closely mutually coupled, 4 of them acting in unison will generate >100dB at 1 watt.
Each time the power doubles, the dB generated increases 3dB. Hence 2 watts gives 103dB, 4 watts 106dB, 8 watts 109dB, 16 watts 112dB, 32 watts 115dB, 64 watts 118dB ...
So domestic friendly SPLs will be achieved with less than 1 watt from the amp, the sound levels that would result from pushing anywhere near its 100 watt rating into it would be devastating."

If this is accurate, even at 100db I'm way below the cab's 100w rating. Theoretically, the cab could get to around 120db before I would blow shit up, so for home practicing at 100db or lower, I'm gonna say it's a go.