Combining Speaker wattage rating

[Hamner1]

I think I know the answer, but I want to get a couple other opinions (statements of fact) 1st.
I plan to replace my speakers in my cabinet. The cabinet can run bridged or stereo. I am wonder if running different wattage speakers may pose a hazard to the speakers. Here is the scenario:
The cabinet will be used in stereo/split mode. I plan to run a 120 watt speaker & 70 watt speaker per side. In my mind that means each side could handle 190 watts. The poweramp is rated at 150 watts/side. Will the speakers be in harms way? Will the "1st" speaker inline be slammed with all the wattage & risk blowing? Or is the wattage dissipated between the speakers.

 

[JKD]

Combine them by adding the wattage of the lower powered speakers, since output is shared equally....you risk blowing the lower wattage speaker.

70 + 120 = 2x70 (140) ...

 

[Ampoholic]

You wanted a couple answers, so I'll tell you that JKD is correct. Number of speakers X the lowest wattage rating.

 

[speedemon]

Yes,


what is not really being explained, is that the wattage is being sent/divided among all speakers evenly. So you end up with a cab that can "handle" 2 x the lowest handling speaker. (or 4 x or however many speakers you have, but always a multiple of the lowest power rated speaker).


Depending on the amp or speaker, the wattage can be rated "conservatively" so that a speaker may handle some % more power than it is rated. It WILL blow eventually if heavily overloaded. Also, it's the case that if you don't crank the amp, or even just run it low, you are not getting the "advertised" power output. Some amps cranked will give you more power than advertised. Be CAREFUL!

Don't listen to me, here are a pair of authorities on it;

http://www.scumbackspeakers.com/faqs.html

http://www.webervst.com/sptalk.html

My favorite rule of thumb with tube amps is to run 2x amp rating in speaker power handling.

there is no "hazard" in mixing speaker wattages, (lots of amp makers do this with their cabs) just need to remember the rule. However, mixing speaker impedances (like 8 and 16 ohms) is a bad idea, as your amp will not match the speaker load impedance.

So, if you are looking to do a Manowar tribute show, or generally blast out the audience, you should add speakers to your setup.

good luck, and read the links!

 

[Hamner1]

Hey all thank you for setting the record strait for me. Also those links are definately some good info. Thank you Speedemon.

Upon further reading of the Velocity 300, in split mode at 8ohms per side it is only dishing out about 75 watts (according to the manual), so 140 watts per side is sufficient, nor do I really need to worry about putting a huge power handling 2nd speaker per side in there (& as stated above wouldn't have helped me if it truly was putting out 150 watts :lol: ).

Yeah I wouldn't be mixing resistance values. I at least was right on how to calculate resistance with series & parallel connections.