How does a DVC speaker have the same electrical capacity in parallell and series?

[amartin_72]

I have often wondered..

If you have DVC 4ohm speaker and wire it to 8 ohms and have say 450 watts going through it, you would have 60 volts and 7.5 amps

but if you run 450 watts through the same speaker wired in paralell to 2 ohms 450 watts would then draw 15 amps. From what i know amperage =heat so speaker disspate the 15 amps the same as if it only had 7.5 amps through it?

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[jrz126 10+ year member]

watts = power, which can be converted into different forms.

So P(out) = P(audio output) + P(heat)

I dont think many subs would function too well if all 450watts were turned into heat.

 

[jujumantb 10+ year member]

amperage =heat

no, amperage = sound + heat. That power is mostly converted into mechanical energy which is then converted into sound energy, only a little bit is turned into heat.

edit: booo! im slow...

 

[amartin_72]

Well if i take the same, very small wire and run say 500 watts through it on an 8ohm load it will get hot before a wire that is running 500 watts into say a .25ohm load and much higher current, right?idk maybe im retarded

 

[bonesninja 5,000+ posts]

wire size is dictated on one factor alone....current. So technically, the more amps you run thru a wire, the hotter it will get. Thats one reason why more strands in a wire the better because current travels only on the surface of each strand...the middle of a wire is basically wasted, therefore the more strands the better current carrying capacity and less heat buildup

 

[helotaxi 5,000+ posts]

It comes down to how the current flows in a parallel circuit compared to a series circuit. In a parallel circuit, the voltage is the same on each load and the current through each load is determined by the resistance of that load via V=IR. In a series circuit, the current is the same through each load and the voltage is determined by V=IR.

Example: Same speakers one wired to 8 ohms and the other wired to 2 ohms. Input power is 8 watts (cause it makes for easy math with round numbers) into each load. In the case of the 8 ohm load we have 8V and 1A making up our 8W. There is a voltage drop of 4V across each coil and the current of 1 A is the same for each coil. Each coil is seeing 4W. For the parallel wired speaker we have 4V and 2A making up our 8W. The voltage is the same across each coil and they flow current IAW V=IR. Each coil sees 1A and combined with the 4V gives us 4W through each coil. You will notice that the voltage and current end up exactly the same through each coil.

BTW-subs are really only on the order of 1% efficient, all the rest of the power really is lost as heat.