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Cabinet power handling
- Thread starter Jaruquin
- Start date
RMS
The power rating is the amount of power that cabinet can accept before the voice coils melt.
This means if you input a 400 watt sine wave into the cab, it will accept this power level without melting.
It has nothing to do with frequency, as most cabinets run out of driver excursion (cone movement) long before they reach the maximum power rating.
The real power limit is the frequency where the driver reaches excursion limits, within your operating range.
99.999% of the time, this frequency is somewhere above low E (41 Hz).
The power rating is the amount of power that cabinet can accept before the voice coils melt.
This means if you input a 400 watt sine wave into the cab, it will accept this power level without melting.
It has nothing to do with frequency, as most cabinets run out of driver excursion (cone movement) long before they reach the maximum power rating.
The real power limit is the frequency where the driver reaches excursion limits, within your operating range.
99.999% of the time, this frequency is somewhere above low E (41 Hz).
Mr. Foxen
Commercial User
Which to go by: None of them. The rating is is the cab loud enough whilst sounding right on a scale of yes to no. And watts tell you nothing about that.
The 400 is a more reasonable figure that most manufacturers "800 watt" 410 cabs that wear the 800 watt spec.
Can't really generalize, and there are no measurements of bass cabinets
But it's highly suspect that any bass cabinet is able to get any louder than half it's rated RMS power.
A cab rated 400w RMS will probably peak at maximum bass volume at 200w RMS
Anything past 200w fead into it is wasted as heat.
Buy cabs with total wattage rating of 2x what the amp puts out. Get more cones (of the same design) to get louder.
But it's highly suspect that any bass cabinet is able to get any louder than half it's rated RMS power.
A cab rated 400w RMS will probably peak at maximum bass volume at 200w RMS
Anything past 200w fead into it is wasted as heat.
Buy cabs with total wattage rating of 2x what the amp puts out. Get more cones (of the same design) to get louder.
None of them.
They're all bogus, even the RMS rating is bogus, since wattage cannot be measured in root mean squared terms; that works for AC sine wave voltages only, not power. Best thing to do is listen to it and turn down if you need to.
None of them.
Yes, there's only one kind of watt and it's calculated from RMS voltage/current, but the (bogus) convention is that "RMS" power is used as shorthand for continuous output power.
There is the argument that continuous output power is not a valid parameter as real life program material doesn't maintain a continuous level. So we get burst and peak power ratings, which might better reflect the signals that an amp deals with in real life but without an agreed standard and without the test conditions being explicitly stated, there's not much to go on.
It really depends on how many of those 650 watts you'll actually be sending to the cab. Even if your peaks hit 650 watts, the average power is probably going to be less than half of that unless you crank it to max and play with a bow or if you use extreme compression.
No. You are getting too hung up on this. You will (should) not be running your amp full tilt all the time. Any decent 212 or 410, or high end 115 should be ok. Just use your ears and some common sense.
Mr. Foxen
Commercial User
All this depending stuff is why watts are a useless measurement. Get amp you like features of, add cabs you like the sound of until loud enough.
This. It's confusing, we know. All you really need to know is, simplified : 1. A 300-500 watt amp is loud enough for almost ANY gig. 2. Connecting one 410 to it will be very loud. But if you turn up past what the cab will do, the cab may blow up. 3. If one cab isn't loud enough, add another one.
My problem now is I got 240W going into a 4x8 250W @ 8ohm cab. I have to put my volume at 75% to keep up with the band. It's a SWR sm-900 so I have some options. Wanted to go bridged @ 8ohms 650W. Was think 2x12 or 4x10. I like the punch of the 8s but not enuff wattage or speaker area for what I need.
Mr. Foxen
Commercial User
Pretty much everything you said there indicates you are assuming things that are not so. Not sure if it is on purpose.
240w is nearly as much as an SVT, which you'll struggle to not be loud enough with. But watts don't mean anything to volume.
Speaker diameter tells you nothing about volume.
Cab watts tell you nothing about volume.
Knob position tells you nothing about volume.
Bridging is something to generally avoid.
'Punch' is not a function of diameter.
240w is nearly as much as an SVT, which you'll struggle to not be loud enough with. But watts don't mean anything to volume.
Speaker diameter tells you nothing about volume.
Cab watts tell you nothing about volume.
Knob position tells you nothing about volume.
Bridging is something to generally avoid.
'Punch' is not a function of diameter.
I don't get this and you're not the first to say it. Provided you're aware of what's involved, i.e. minimum load impedance in bridge mode is twice that of the individual channels, and of course the increase in available power, I can't see any problem. I've been bridging power amps into 8 ohm cabs for a long time and never had any trouble.
Mr. Foxen
Commercial User
The stuff in the rest of the post says this isn't the case. And double voltage swing is often more than speakers can make use of and thus not useful.
It's not on purpose. Trying to figure out an answer to my problem. I'm not well versed on cabs. So if you have some answers please enlighten me.
Mr. Foxen
Commercial User
What is the actual problem? All I can figure there is you don't like how far you turn the knob on your head. You can fix that by pulling it off and putting it back on a bit further round.
