# how to calculate speaker & AMP total watts???



## ANTHONY-GATLIN (Jul 12, 2009)

how to calculate my speakers and AMP wattage total ?
for example if i have 
{1} sub 1000 watts 
{1} mid range 200 watts
{1} tweeter 100 watts
{1} amp 2000 watts
does that means that have a total of 3300 watts ?
i see some people post that they have 30,000 watts and 40,000 
how do they know how much watts they have


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## schmiddr2 (Aug 10, 2009)

You would need to clamp your power wire to determine the Amperage draw and the exact Voltage under load. Then figure in efficiency.

Your cars Voltage x the Amperage draw x amps efficiency = Watts.

EDIT: And speakers don't have Watts. It makes no difference what the speaker is rated for in terms of your systems total Watts.


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## ZAKOH (Nov 26, 2010)

ANTHONY-GATLIN said:


> how to calculate my speakers and AMP wattage total ?
> for example if i have
> {1} sub 1000 watts
> {1} mid range 200 watts
> ...


And what's the point of this quite useless exercise? After having built my cars stereo system, it hasn't occurred to me to sit and think about this. I know that a lot of car manufacturers like to boast specs like "we got a 600watt 11-speaker system", which is IMO a quite meaningless claim..

But looking at your list, clearly speakers don't quite generate the watts. Moreover, "2000 watt" amplifier power is quite meaningless, unless that's RMS wattage.


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## ANTHONY-GATLIN (Jul 12, 2009)

ZAKOH said:


> And what's the point of this quite useless exercise? After having built my cars stereo system, it hasn't occurred to me to sit and think about this. I know that a lot of car manufacturers like to boast specs like "we got a 600watt 11-speaker system", which is IMO a quite meaningless claim..
> 
> But looking at your list, clearly speakers don't quite generate the watts. Moreover, "2000 watt" amplifier power is quite meaningless, unless that's RMS wattage.


"2000 watt" amplifier power is quite meaningless ? as i said for example


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## minbari (Mar 3, 2011)

in your example you would have 3000 potential watts. as mentioned, to get your actual watts, you have to clamp each amplifier and see what it is really putting out into the speakers you have connected. you will be surprised how different it is


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## Fricasseekid (Apr 19, 2011)

Why must you clamp it and figure in for amperage draw? 

Can't he just use a DMM to measure output voltage, square the voltage, and then divide that figure by the resistance in ohms?


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## minbari (Mar 3, 2011)

Fricasseekid said:


> Why must you clamp it and figure in for amperage draw?
> 
> Can't he just use a DMM to measure output voltage, square the voltage, and then divide that figure by the resistance in ohms?


can you calculate the all the impedance across all the frequencies? we are not talking about DCR here and impedance changes over freq. so clamping is the only way to tell.


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## ou812 (Oct 25, 2008)

What is the point?....Bragging rights?


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## minbari (Mar 3, 2011)

ou812 said:


> What is the point?....Bragging rights?


didnt say there was a point 

he ask how it could be done and we answered him


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## Fricasseekid (Apr 19, 2011)

minbari said:


> can you calculate the all the impedance across all the frequencies? we are not talking about DCR here and impedance changes over freq. so clamping is the only way to tell.


Ok, dumb question...

DCR?


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## minbari (Mar 3, 2011)

DC resistance


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## ANTHONY-GATLIN (Jul 12, 2009)

minbari said:


> in your example you would have 3000 potential watts. as mentioned, to get your actual watts, you have to clamp each amplifier and see what it is really putting out into the speakers you have connected. you will be surprised how different it is


thank you for a simple answer


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## sqshoestring (Jun 19, 2007)

You potential watts is all your amps wattage added together. Peak watts don't really mean much and often amp makers fudge those numbers if there is no RMS rating, so hard to say what it has with no RMS rating at X volts supply. You have to estimate the efficiency but then you can clamp the 12v input and get an idea what it is doing when ratings might be bogus.

The amps are voltage pumps and the speakers are what allow amperage to flow depending on their impedance (lower ohms means more amperage means more watts (watts = volts x amps)). The amp will put the same voltage to speakers unless it is regulated, those amps show the same watts to different loads (speaker ohms). Impedance is same as resistance at a given frequency, but resistance does not change with frequency like impedance. An ohm rating on a speaker is really just a basic rating not an exact reading, it is really only useful as a way to match an amplifier to the speakers. An amplifier should be able to drive a load close to its ratings and it will not be exactly as rated as every speaker is different and even the install can change the impedance.

While an amplifier can output X wattage to speakers, a speaker can take a variable amount of power before it pukes. It takes time to heat up the voice coil so it can handle more power for a moment. It depends on the enclosure you use if it will xmax or not and cause mechanical damage. So one person can run double rated to a sub and another just under rated, yet the smaller amp might blow the sub and the overpowered one never....because of use, type of enclosure/music/abuse the user applies to it. So speaker wattage ratings are much like ohm ratings, just a ballpark rating. If you look at JL subs they give you a range of power vs risk to damage, that is more realistic. When you get into cheap equipment they like to fudge these numbers and make them ever larger, however a peak rated amp and sub might match up ok.


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## minbari (Mar 3, 2011)

sqshoestring said:


> ............(lower ohms means more amperage means more current *(current = volts x amps)*). The amp will put the same voltage to speakers unless it is regulated, those amps show the same watts to different loads (speaker ohms).


is this a new ohms law I dont know about?

amps and current are the same thing.


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## sqshoestring (Jun 19, 2007)

minbari said:


> is this a new ohms law I dont know about?
> 
> amps and current are the same thing.


LOL you are right it should be "watts" :blush:

I edited it, can't have that kind of misinformation on here....doh. Must be the cold medication lol.


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## ANTHONY-GATLIN (Jul 12, 2009)

sqshoestring said:


> You potential watts is all your amps wattage added together. Peak watts don't really mean much and often amp makers fudge those numbers if there is no RMS rating, so hard to say what it has with no RMS rating at X volts supply. You have to estimate the efficiency but then you can clamp the 12v input and get an idea what it is doing when ratings might be bogus.
> 
> The amps are voltage pumps and the speakers are what allow amperage to flow depending on their impedance (lower ohms means more amperage means more watts (watts = volts x amps)). The amp will put the same voltage to speakers unless it is regulated, those amps show the same watts to different loads (speaker ohms). Impedance is same as resistance at a given frequency, but resistance does not change with frequency like impedance. An ohm rating on a speaker is really just a basic rating not an exact reading, it is really only useful as a way to match an amplifier to the speakers. An amplifier should be able to drive a load close to its ratings and it will not be exactly as rated as every speaker is different and even the install can change the impedance.
> 
> While an amplifier can output X wattage to speakers, a speaker can take a variable amount of power before it pukes. It takes time to heat up the voice coil so it can handle more power for a moment. It depends on the enclosure you use if it will xmax or not and cause mechanical damage. So one person can run double rated to a sub and another just under rated, yet the smaller amp might blow the sub and the overpowered one never....because of use, type of enclosure/music/abuse the user applies to it. So speaker wattage ratings are much like ohm ratings, just a ballpark rating. If you look at JL subs they give you a range of power vs risk to damage, that is more realistic. When you get into cheap equipment they like to fudge these numbers and make them ever larger, however a peak rated amp and sub might match up ok.


thank you


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