How to match the wattage between the cab and the amp?

anarchipur · #1 08-30-2010, 08:45 AM

I am still following the topic matching a cab to an amp.
In the net I found some contradictory discussions..

What I read is if the amp is much stronger than the cab it can damage the cab if too loud. however if the amp is weaker than teh cab it can even easier damage the cab because the amp must be turned louder to get juice into the cab and can thus cause clipping which is unhealthy for the cab.
Some people write cab and amp should have no more than +-100 Watt difference. Others write it doesn't matter.

So what is the truth?

My question is if my amp works 375 Watt at 8 Ohm and 600 Watt at 4 Ohm, what should be the wattage of the cab that I buy at 4 or 8 ohm respectively?

Anyone with an idea?

Plstrns · #2 08-30-2010, 08:51 AM

Within reason, any amp can damage any cabinet. It's up to the end user to adjust the volume knob.

Matthijs · #3 08-30-2010, 09:15 AM

Do a search on talkbass, because there's a lot of fiery debate on this. You can have my take on it, but be prepared for some different opinions. That said: I agree with plstrns before me:

There is no perfect combination of amp and cab. Most amps can potentially be to loud for most cabs. That can also be true for a low rated amp, either because you've turned up the lows to high for your cab or because the actual power at a distorted level will be higher that the rated power level, as the rated power level is the level without distortion. Forget about the dangers of a clipped sound. A clipped waveform in itself presents no danger.

C.Linton · #4 08-30-2010, 10:19 AM

I agree it can be confusing, I too have seen plenty of contradicting statements. All I can do is try to match the wattage ratings as close as possible without going too far in either direction.

anarchipur · #5 08-30-2010, 10:24 AM

Quote:

Originally Posted by C.Linton

I agree it can be confusing, I too have seen plenty of contradicting statements. All I can do is try to match the wattage ratings as close as possible without going too far in either direction.

Thanks guys! What does it mean to match the wattage ratings? The answer could help me to move forward

Plstrns · #6 08-30-2010, 10:33 AM

Let me explain, no there is no time, let me sum up.

Enclosure wattage handling ratings are of NO VALUE, other than marketing. SO, it is no more than a guess to match amp outputs to handling capability.

There is no such thing as over, or under powered. If you want the very maximum performance from your enclosure, buy as much power as you can afford or want to carry.

There is a volume knob. When you turn on your car radio, do you have a feel for it's maximum capability? Sure you do, pro sound works the same way.

jazzmonkey · #7 08-30-2010, 10:34 AM

In your case matching wattage ratings would be getting as close to 375W @ 8ohm as you can, and getting as close to 600W @ 4ohm as you can.

From my understanding, a cab will let you know when you are pushing it too hard. It is up to you to adjust your EQ or volume accordingly.

It sounds like you are using a GB shuttle 6.0 or shuttlemax. If you get a cab rated less than 375@8/600@4, just pay attention to the speaker when cranking it up and you should be fine. If you are underpowering just watch out for audible distortion and also watch out for the clip lights on the head, the lights will let you know when you are pushing the head too hard.

I believe Plstrns hit the proverbial nail. It is up to the amp user to adjust the volume in either situation.

BassmanPaul · #8 08-30-2010, 10:42 AM

If you have, for example, a speaker system capable of handling 400W and an amp that can supply 800W. If you only use 200W of the amps power you'll never blow the cabinet unless you really boost the lows.. OTOH if you need to use 600W the cabinet will soon be toast.

What is needed is enough speakers to play the gig. Trying to make up for insufficient speakers by adding power will get you nowhere. Once a speaker gets as loud as it can adding more power will just burn it out.

What ever you go for you have to listen to your rig and take note of any signs of stress. If you hear anything that shouldn't be there turn down.

Paul

BassmanPaul · #9 08-30-2010, 10:47 AM

Quote:

Originally Posted by Plstrns

There is no such thing as over, or under powered.

While under powering is a myth over powering a cabinet is very very real!.

Paul

Plstrns · #10 08-30-2010, 11:22 AM

Quote:

Originally Posted by BassmanPaul

While under powering is a myth over powering a cabinet is very very real!.

Paul

Perhaps I should've wrote -No such thing as having too much available power. That's what I meant anyway

billfitzmaurice · #11 08-30-2010, 11:36 AM

Quote:

Originally Posted by anarchipur

Anyone with an idea?

Look at the top of the forum first page.

AMPS FAQ!! Info on OHMS, Allsize RIGS-OverUnderPowerCabs DIY TechTalk-Links

tekhedd · #12 08-30-2010, 11:38 AM

Quote:

Originally Posted by Plstrns

Perhaps I should've wrote -No such thing as having too much available power. That's what I meant anyway

I have blown out speakers with clean power trying to keep up with a guitar player's volume. Since then, I like to have the amp close enough to "expected melting point" of the speakers that I can hear distortion before it gets loud enough to melt the voice coil.

But that's just as an aid for knowing when to turn down. There is no such thing as excessive power.

BassmanPaul · #13 08-30-2010, 11:39 AM

Quote:

Originally Posted by Plstrns

Perhaps I should've wrote -No such thing as having too much available power. That's what I meant anyway

If you go that route you do face the danger of a blown driver if the rig gets away from you. My cabinets are rated at 350W and my new amp can deliver 450W into each. I've never even been close to actually using that power so everything is cool. Sometimes though a band will get louder over the course of the gig and one can get carried away.

In all this it's your ears that you have to use.If you're hearing bad things you have to turn down.

Paul

RickenBoogie · #14 08-30-2010, 11:50 AM

Always best to use your ears, rather than a published, meaningless number, as you'll find on most bass cabs. Even then, the rating tells you at what wattage the voice coil will burn up, NOT how much actual power the cab can handle.

**Kelly Lee** · #15 08-30-2010, 09:09 PM

Quote:

Originally Posted by billfitzmaurice

Look at the top of the forum first page.

AMPS FAQ!! Info on OHMS, Allsize RIGS-OverUnderPowerCabs DIY TechTalk-Links

Thanks Bill.

Yes, read the threads located at the link Bill provided. Look specifically for the "Over/Underpowered" section and you will find very detailed discussions with industry engineers, touring pros, and weekend warriors.