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these r the amps/speakers MAX ratings now on a speaker the max rating is the max power it'll take but when u start putting the max power into em they can distort

and for amps well an amp will very rarely output its MAX power figure i.e 1000w n when it does its only for a milisecond or 2

so how do u work out how much power your amplifier is putting out? or whats the best amount of power for the speaker?

well the speaker calculation is rather complex so general rule of thub is the RMS (root mean square) or nominal power it is most efficent or works best with is usualy about half the quoted max power same sorta rule can be applied to an amp

now if you wanna work out more exact what the output is heres the calculation..

VxAxE

V= voltage

A = amperage (fuse rating what current the amp draws ie 20amp0

E = efficency (different for all types of amps general Class D or monoblock amps r 70-80% efficent and Class A or B are between 50 and 60% True Class A is about 90% but theres hardly any Pure Class A amps out there n the ones that are are a few grand)

so for example lets take a 1000w MAX rated amp with a 40amp fuse which is a monoblock (Class D)

ok Volatge when a car running is 13.8v 99/100

amperage well it has a 40 amp fuse so this is 40

efficency we know class D's r roughly 70% efficent so this is 0.7 as 100% = 1

so..

13.8 x 40 x 0.7 = 386.4 so lets call it 385 this is our RMS (root mean square or nominal power output) that the amp puts out

so as you can see it doesnt really matter what it says on the box its more what fuse is in it/what current it draws

but then again most amps will not draw the full amount of current which the fuse is rated at or it would constantly pop, so we can give this a 5-10% leaniancy so in our above example would actually be 36-38 amps therefor...

13.8 x 36 x 0.7 = 347.76 lets round it down to 345

thats a 1000w amplifier that only actually puts out 345 watt

now lets do a 2 channel amplifier which is Class B..

quoted 400w x 2 MAX and has a 40amp fuse rating

now from our above equation we know about the current leniancy we have to take into account which in this case again would be 36amp and efficeny is 60% so 0.6 for E

so

13.8 x 36 x 0.6 = 298.08 now lets round this one up slightly just to make things simpler so 300w

now we have 2 channels so simply divide by 2 which would be 150wrms x 2

now for the best sounding system posiible you really want to be matching the RMS values of the amps to the speakers and as stated above if you cant find the RMS value for the speaker half the max rating which will give u a rating slightly higher than the rms but match this and the speaer should perform at its most efficent

i could go on alllllll day about amps speakers and setting a system up properly but the average joe doesnt need to know all this however i feel that people like to get the most out of thier equipment so when your using a set of 200wrms speakers and the amp is only giving them 20wrms theres quite a bit going to waste!

if you feel theres anything iv missed please feel free to tel me or if u think ive done something wrong please correct me and i hope this helps people in future when choosing an amp and speakers....