Cabs: figuring out total wattage

[tone]

Can anyone explain to me how you go about figuring the total wattage of a speaker cab, when wire in either series or parallel? I always thought that you just add them all up no matter what. But i just read something about multiplying the lowest wattage speaker by the number of speakers if it's in series? What wiring do most manufacturers like Mesa, Marshall, Fender, Bogner etc use? And, how can you tell which method is used?

Thanks!

 

[Rich_S]

Re: Cabs: figuring out total wattage

Asuming they're all the same impedance, and wired some way that they all get equal wattage, then it's the lowest wattage speaker, multiplied by the number of speakers. An example:

Say you have a 4x12 cab, with four 16-ohm speakers wired series/parallel for a total load of 16 ohms. The speakers are two V30's (60 watts each) and two G12H30's (30 watts each). Total power for the four speakers is 180 watts, but...

The power input is split evenly. If you plug in a 180-watt amp and crank it, each driver will get 45 watts, and the G12H's aren't going to like it. So, the total wattage for this cab is really 30 x 4 or 120 watts. (Though it's best to leave some margin, so call it a hundred.)

The above works when the power to all the speakers is the same. Recently, someone here asked about mixing an 8-ohm speaker with a 16-ohm speaker. In these cases, the power is not balanced and you have to make sure each can take the power that will be flowing through it.

Do you have a specific combination in mind?

 

[tone]

Re: Cabs: figuring out total wattage

Thanks Rich S!
So it does'nt matter if they're wired in series or parallel, you always multiply the lowest wattage speaker by the number of speakers?

I'm using a 2x12 cab with two vintage 30's. So 120 watts? And I was thinking of switching one of them out for a CL80 or black shadow MC90 just to experiment. In that case, that total wattage would still be 120 watts?

 

[Rich_S]

Re: Cabs: figuring out total wattage

In that case, that total wattage would still be 120 watts?

Yup.

 

[tone]

Re: Cabs: figuring out total wattage

Thanks Rich_S.
So this would be true, no matter what way of wiring is used? (series or parallel?)