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 - - - 50watt output on 22 guage speaker wire? Something doesn't add up...

You know, I was thinking about my new setup... I power my speakers through my headunit. It says it can output "4x50watts" - I'm assuming this means 50 watts per channel (Pioneer DEH-7500MP for those of you who care). And yet, the wire that goes to the speakers is dinky 20 or 22-guage wire. Seems to me that 50 watts would require more than 22-guage wire... if P=IV, well, I am under the impression that max voltage would be 14.4, and say the speakers were being run at the full 50watts, that would mean the current would be 3.5 amps. Now, this adds up according to this page: http://www.bderc.com/howto/chapter3/page3.html. However, say that the speakers were being run at their full 220 watts... that would mean a current of 15.2 amps - something that would need 14 or 12 guage wire. I could understand how 18 guage wire could fit onto the speakers' small connectors, but not 12 guage wire.... I must be missing something here... can someone explain? Similarly, I helped my friend set up a system with an amp powering a sub. The amp needed gigantic 4 (maybe 6) AWG wire to be run from the car battery. And yet, the output to the sub is again only a dinky 20 or 22-guage speaker wire. If all thats needed to power the sub is the amount of current that fits onto the 20 guage wire, where does all the extra current that came in on the 4-guage wire go?

not sure i understand the question but here goes. you have pioneer radio 50x4 you want to know why it has small gauge output wire. well heres how i have come to see it consumers are stupid plain and simple and the large companys know that. they have to be competitive so if one can say 40x4 the other will say 50x4 so the unknowing consumer will think they are getting more for there money. have you ever seen a 50x4 amplifier and felt the weight of it thats mostly power supply weight. theres no way your going to get that power supply inside of a radio to run 50x4 you would be connecting your head unit to 10 awg wire.your friend's amp was what kind i haven't seen an amp with wires coming out of it in years they all usualy have connectors to screw wire under neath using either plain wire or some type of crimp on connector.heres another thing to think about, audio is a/c power not d/c same rules dont apply.

Those head units that advertise 50x4 generally test somewhere between 12x4 and 17x4 rms. The good news is that nice speakers generally will do pretty well with that amount of power - it sounds like you would agree.

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Originally posted on 11-28-2003 by installforyrs
not sure i understand the question but here goes. you have pioneer radio 50x4 you want to know why it has small gauge output wire. well heres how i have come to see it consumers are stupid plain and simple and the large companys know that. they have to be competitive so if one can say 40x4 the other will say 50x4 so the unknowing consumer will think they are getting more for there money. have you ever seen a 50x4 amplifier and felt the weight of it thats mostly power supply weight. theres no way your going to get that power supply inside of a radio to run 50x4 you would be connecting your head unit to 10 awg wire.your friend's amp was what kind i haven't seen an amp with wires coming out of it in years they all usualy have connectors to screw wire under neath using either plain wire or some type of crimp on connector.heres another thing to think about, audio is a/c power not d/c same rules dont apply.

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most of your amps on the market have connector that is able to accept a 1/4 inch open ring or fork terminal wich come in a variety of sizes for the wire to adapt to up to 8 awg wire but the end that goes under the screw is only1/4" hope this answers your question if not tell me the model of amp and i will do better. a class a aplifier has a lower current intake to watt output than a class d. the reason is the lower thd in the class a amp then in the class d amp . the a will give you lika 45/50 in to out and the d will give you a 75/80 input to output. thats why the d is only used for subs to much thd TOTAL HARMONIC DISTORTION. you wouldnt want that in your mids and highs. never hear it in the subs most of the amps on the market are a/b amps kinda the best of both worlds unless youknow what your doing with them alot of sound Q competitors use highQuality tubed driven amps wich are class a Aand alot of spl vehicles use class d amps. hope this answers the second part of the question what happens to the current going in . I again tell you that the output is a/c not d/c same wire rules dont apply.

V into the amp is a lot lower than V out. So if you look at the P=IV formula you see that if V increases and P stays the same the I has to decrease. Also, P doesn't stay the same - it drops quite a bit due to the inefficiencies of the amp as Installer mentioned.

Those two factors alone make it pretty easy to see how the current demands (and power wire needs) of a speaker can be significantly less than that of the amp driving them. Then when you consider a multichannel amp that is dividing that power between/among 2 or more speakers the current decreases even more.

"...where did all the current that came in on the 4-guage wire go?"

Heat.

Amplifiers are far from efficient, as the previous poster stated, and well over half of the power that your amp requires to operate gets converted to heat in the process of amplifying your signal...hence the massive power cable, massive heatsink, and tiny speaker cables.

play w/ this one for a bit volts/ohms=amps, amps x volts=watts so lets play w/ my amp (memphis studio 1000D) running at 1 ohm does 1100 watts so that means the square root of 1100 is 33.1 so 33.1/1=33.1, 33.1 x 33.1=1100 watts so even though it starts out as 13.8 volts and 80 amps it ends up as 33.1 volts, 33.1 amps (not including loss)