Separate Head + Cab

[LeftyLB]

In a recent thread there was a debate about whether speakers needed more or less wattage than the head they were being matched with.

The general agreement in the threadwas that the speakers should be less. This would be supported by the fact that the Ashdown MAG range offers a 300w head and three different cabs. The 2x10" cab has a rating of 200 watts and the 1X15" has 250w. There is also a 4x10"

Therefore, if I were to match the 300w head and the 200w 2x10" and needed to crank it up, am I being limited to 200w of output?

Baring in mind that my Stingray will be DI (either direct from the bass or the DI out on the amp) into a rig that pushes out 2K, I don't need to worry about the out of house sound.

However, some gigs, with a full inhouse foldback/ monitor system results in a very loud stage and I want to ensure that my amp is not struggling to be heard by myself and the others on stage. - We have had the "let's all turn down" conversation many times!

Therefore in real terms is 200watts louder than I appreciate and I would probably not need more than 200w just for stage monitoring?

Sorry the thread is long, but I don't want to make a wrong choice again.

Thanks

Liam

 

[Psychicpet]

ya, dillema ... if all else fails on really loud nights, ask to get a bit of yourself in the monitors or do the really uncool thing of putting your amp beside your monitor and point it upwards directly at you, and the FOH engineer will like you though because then he's got less direct stage volume to deal with....... or just tell your guitarists and drummer to get their "mommy" issues solved and play quieter!!

 

[Aussie Mark]

Speaker cabinet ratings are usually RMS, whereas your amp power output is a continuous (or maximum rating). Even if you're running your head flat out at 300 watts all night, the nature of bass music means that it is not a continuous sound (ie. there are peaks and troughs, silence between notes etc). A 200 watt RMS cabinet can easily handle 200 watts continuously, and 400 watt peaks, which is why you can safely run a 300 watt head with a 200 watt speaker cabinet.

Now, the thing you haven't told us is the impedence of the speaker cabinet, or what speaker load (impedence) the head's quoted power rating is based on.

For example, if the head is 300 watts @ 4 ohms, and the cabinet is a 8 ohm cabinet, the most power the cabinet will receive from that head is around 200-225 watts. On the other hand, if the cabinet is a 4 ohm box, then it will see the full 300 watts from the head, which is a nice match.