8 ohm vs 4 ohm ??

[PATTY1]

i'm getting 500 watts running my SWR amp in bridge mode into an 8 ohm speaker cabinet, i wanted top buy a gallien kruger 800RB as a back up amp but it says will only put out 200 watts into an 8 ohm speaker cabinet......does this mean it will only be as half as pwerful as my SWR rig, because sometimes when playing larger bars i'm using 3/4 volume on my SWR, meaning the 800RB won't be loud enough for me ??? is this true???

[Rick Auricchio]

The GK will only put out half the power, but wattage is the least important measurement of loudness.

Loudness is totally determined by the speaker cabinet design. There are very loud cabs, and very weak ones. The wattage rating on a cabinet simply tells how much power will melt the voice coil. Most cabs will fart out long before they hit max power.

Chances are you're not putting anywhere near the SWR's full power into your cabinet anyway. Having a four ohm cab lets the amp put out more wattage, but that probably isn't an issue here.

The only way to be sure is to test both amps with your cabinet.

[Double Agent]

You really need to try it. You could probably get the same VOLUME out of the 800RB as you get from your SWR. The question is, will you have enough headroom? But, something tells me that you can run the GK wide open (volume maxed, or nearly maxed) and, as long your EQ is not set to extreme positions, give that 4x10 all the power it needs.

Remember that wattage from the amp is not as important as the amount, and the efficiency, of speakers in determining loudness. However, you could start to run out of clean headroom really quickly with lower wattages, especially if you EQ a lot of bass boost in your signal.

[Zooberwerx]

Let's prioritize: first and foremost, you need a back-up. What's your budget? What other components are available or have been considered? I'll make the assumption you're wanting something comparable in terms of power and performance. If that's the case, then the GK may not be the best choice.

Riis

[Rick Auricchio]

Originally Posted by Double Agent

...give that 4x10 all the power it needs.

The OP never said anything about the configuration of the cabinet; why do you think it's a 4x10?

[Double Agent]

Originally Posted by Rick Auricchio

The OP never said anything about the configuration of the cabinet; why do you think it's a 4x10?

I don't know.

I think I am losing it. I thought I read that the cab in question was a 4x10, but you're right...the OP says nothing about the cab configuration and it's too late to edit it now, so I guess everyone will know that I was hallucinating this morning.

Back to your regularly scheduled topic.....

[Rick Auricchio]

It isn't like I haven't done the same thing...

[Bassamatic]

Loudness is not directly proportional to amp power. It takes 6-10x the amp power to sound twice as loud to your ears.

This has to do with the physics of the sound dispersion from the speaker.

The ability of the amp to respond to peaks is more important than the actual power rating.

[B-string]

If you want a backup amp close to the same wattage at 8 ohms get a 1001RB.