simple questions -

[Matthew Bryson]

I've read (many times) here that when matching up a speaker cab and an amp head that you shouild use an amp that provides more power than what the cab is rated to handle so that you have lots of clean head room. Am I right so far?

What does this mean? Does this mean that you'll blow your speakers before your amp starts clipping?

When you have all that power - if you have twice as much power as your cab is rated for, how do you know when you've turned up too much?

If my cab is rated for 200W noise / 400W program / 800W peak am I going to be underpowered with the 400W head I am getting?

 

[Matthew Bryson]

I should have titled this: how do keep from damaging my full amp? ...but seriously - this is a real question.

 

[seanm]

You will be fine. Don't worry about it and play bass

 

[Saetia]

It really depends on how you are using the amp, and in what setting. You can get by with a 200 watt head into a 400 watt cab if you are using it for practice or a light mix that isn't very loud. If you start adding a loud drummer, and guitar you will want to try and match the rating on the cab. If they are really loud and maybe have distortion and you are pushing your amp really hard, you will need something that is rated higher then your cabs rating so you have more head room and run a lesser risk of clipping. When you have a head that has more power then what your cab is rated for you have to keep in mind not to push the cab to hard. If you have tons of head room and aren’t getting the volume you need, you either need to get a bigger cab, a cab that has a better efficiency or add another cab to the set up. This way you avoid pushing your cab too hard.
Peace
-Ben

 

[BruceWane]

You can safely run up to twice the RMS rating of the cabinet, AS LONG AS YOU ARE CAREFUL TO AVOID CLIPPING. Now, that doesn't mean that the second a clip light flickers, speaker cones are gonna go flying across the room. It just means that if you hear ANY distortion, check your clip indicators immediately. The onset of clipping will be pretty obvious - you'll hear the attack of your low notes breaking up. When you hear that, look at the amp and see if the clip LED's are lighting. Turn down the volume until they don't light.

And note that I said the RMS rating - not "program power", not "peak power". Those are not really standard terms. I won't get into exactly what RMS means and how the rating is calculated, but from the numbers you posted, 200W is the RMS of your cabinet., so you'll be fine with a 400w amp, just don't keep pushing it if things start to sound bad. Things can change while playing; it's really common to gradually pluck harder and harder throughout a gig, so a gain setting that's good at the beginning of the gig might be too high once you get a bit pumped.