I guess what I am really looking at is - with a 200W head powering 1 15 speaker- if I throw this 4x10 in the mix- whats the least I go and still sound good. I don't need a 300W cab if only 100W is going to it right? I just dont understand how this stuff works.
ER IV BLOWN A 4X12" 400W CAB WITH A 150WATT HEAD. i think its because its easier to blow up an amp with distortion than with power..... ie i was running the amp flat out [causing distortion/clipping] i also used to run a simillar cab of a 550watt amp and it never blew... even at full power becaus [i presume] that the signal was clean..... in fact ive blown alot of speakers in my guitar amps because the amp wasnt enouth 4 them and had 2 drve in clipping... er i think?????
ER IV BLOWN A 4X12" 400W CAB WITH A 150WATT HEAD. i think its because its easier to blow up an amp with distortion than with power..... ie i was running the amp flat out [causing distortion/clipping] i also used to run a simillar cab of a 550watt amp and it never blew... even at full power becaus [i presume] that the signal was clean..... in fact ive blown alot of speakers in my guitar amps because the amp wasnt enouth 4 them and had 2 drve in clipping... er i think?????
If you look at the relationship of power and music from a dynamic standpoint, things becom a little clearer.Most music information lives in the lower 1/3 of the total dynamic range.
Speakers can handle short power peaks of more than double their rated power. To handle these peaks, the general rule of thumb is to have 6dB of headroom available, to cover peak dymanic demand. So lets say you have a 100W speaker. In order to power this speaker with just 3dB of headroom, you have to double your power or, 200W. For 6dB you have to double the power again, to 400W (dB are a logarithmic scale).
The problem comes in with the clipping. When you clip, It looks like DC to the speaker. Voice coils do not like DC. They use the constantly changing power level of each cycle for cooling. As you clip, you are forcing the voice coil to respond to more steady state(DC) power. The voice coil heats up, melts or unravels, and shorts.
The rms power to the speaker also increases. If you put an amplifier on a dummy load and looked at the voltage, you will see the rms voltage increase even though the peak voltage does not (oscilloscope and ac voltmeter required). Working Watt's law, P=VxI,
you can see that this increases the rms power ( for ac some vector math is required for accuracy but, close enough for government work). Amplifiers also start throwing out some real trash when they are clipping. There can be nasty spikes that are caused by the amp trying to respond. These are real killers.
I personally have never blown a speaker because it was over powered. But, I have roasted some because they were under powered. An expensive lesson to be sure. Hope this explaination helps.
Speakers can handle short power peaks of more than double their rated power. To handle these peaks, the general rule of thumb is to have 6dB of headroom available, to cover peak dymanic demand. So lets say you have a 100W speaker. In order to power this speaker with just 3dB of headroom, you have to double your power or, 200W. For 6dB you have to double the power again, to 400W (dB are a logarithmic scale).
The problem comes in with the clipping. When you clip, It looks like DC to the speaker. Voice coils do not like DC. They use the constantly changing power level of each cycle for cooling. As you clip, you are forcing the voice coil to respond to more steady state(DC) power. The voice coil heats up, melts or unravels, and shorts.
The rms power to the speaker also increases. If you put an amplifier on a dummy load and looked at the voltage, you will see the rms voltage increase even though the peak voltage does not (oscilloscope and ac voltmeter required). Working Watt's law, P=VxI,
you can see that this increases the rms power ( for ac some vector math is required for accuracy but, close enough for government work). Amplifiers also start throwing out some real trash when they are clipping. There can be nasty spikes that are caused by the amp trying to respond. These are real killers.
I personally have never blown a speaker because it was over powered. But, I have roasted some because they were under powered. An expensive lesson to be sure. Hope this explaination helps.
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