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speaker mismatch

6/9/1998 7:13 AM
speaker mismatch
I have a Mesa dc-5 combo (50 watt) with a single 8 ohm 90 watt black shadow. I would like to hook it up to a cab that I built with 2 16 ohm Weber VST 20 watt Alnico 10s wired @ 8 ohms. I can run each (boogie 12 and cab)into the 4 ohm jacks on the boogie.  
How will the power be divided by the speakers?  
Which should be louder? Can I toast something??  
Bob Hunter
6/9/1998 7:27 AM

Theoretically the power should divide equally between the two 8 ohm loads. Therefore you should get 1/2 power into the Widow and 1/4 power into each of the speakers in the cab. Unfortunately the impedance of speakers is frequency dependent. That means that one speaker will take more top, and another will take more bass. Just to throw another variable into the thing, the speakers will be of different efficiencies, and so they may not turn the extra power they draw into extra volume.  
AS long as you connect the 4 Ohm output of the amp to a 4 Ohm load you're pretty unlikely to fry anything. Try it and see what it sounds like!
6/9/1998 8:16 AM
Jim S.

The Mesa/Celestion 90-watt speaker is relatively efficient. My guess would be that you're going to get noticeably more volume from that speaker than from the pair of vintage-style 10" speakers in the cab. However, even if this turns out to be the case, you still might get a pleasing tonal blend from combining these two very different types of speakers. You certainly can't damage anything with each 10" speaker handling approx. a max of 12.5 clean watts.
6/15/1998 11:18 PM
Steve A.

    To balance the output levels from the speakers something like a Marshall Power Brake could be used to reduce the signal going to the stock speaker. At the higher settings, the Power Brake doesn't alter the signal too much.  
Steve Ahola
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