k, so im lookin at the manny for my head unit. sez it puts out 22w rms at 4ohms. so using ohm's law i calculate voltage (voltage = square root of watts x ohms). so i get v=9.38...
where im going with this: i blew my 3.5" speaker. so i replace it with a bookshelf speaker from an old stereo. this speaker is 6ohm. once again using ohms law i calculate for watts this speaker will be recieving. watts=volts squared divided by ohms. i get 14.666666.... watts.
did i do all the math right? will the speaker be given 14.6 watts rms?
oh and your math didn't account for efficiency of the head unit's amplifier, or the curve of that efficiency at various loads, etc.. but it's close enough. you know the amp is 22 watts @ 4 ohms. you know that'd be 11 watts at 8 ohms, give or take. 6 ohms is half way between that, so all you had to do is add 11 and 5.5 t get about the same result at 6 ohms. much less work
yah, but isn't it true that halving the load doesnt give exactly 2x the power? this is true cuz theres a square in the formulas, yah? if i had some response curves for the HU, i think i might've used em ;-)
yah, i know it's quieter, but i'm happy the crackling of the old speaker is gone!! maybe someday i'll get some real components! ha!
hey does anybody know of any brands that make just 7'' component speakers. I have a 2003 eclipse and it has 7'' front speakers and 6x9 rear but all I can find is 5x7's. Anybody know of any please let me know. preferably if they have 2 ohm speakers. Thanks.
ill prolly have to buy a mounting bracket. is that something I can just get about anywhere. no the 2000-2003 eclipse GTS has factory 7'' front and 6 x 9 rear. the 95-99 had 6.5
ok steve the more I look it looks like it could be 6.75's. The chart I found said 7'' but ill prolly trust your word over that. Is there anyway to check it for positive.
I got 6 3/4 by looking it up on a site. Scosche has a site, so does crutchfield i think. The way to know if speakers will fit without modification is to measure the diameter of the hole in you car and compare it to the listed cutout diameters for different speakers.
yeah how close to doubling the power an amplifier gets by halving the load depends a lot on the amplifier's power supply design.. regulated or not etc.. some are better at coming close to twice the power tahn others.
infinity, i just looked at your calculation again, and you may have gotten the right wattage but you did it completely wrong. the voltage is supposed to be 14.4V, not what you got. you were supposed to calculate for amperage, voltage does not change persay, same goes with home audio or most electronics for that matter. and you plan to get a certification for this kind of stuff? wouldnt want you near my car.
and? all people make mistakes or slips here and there. if you have an interest in something such as electronics i would hope that you have some knowledge in E&M. you used the right formulas and got the right answer but there was some extra thought that needed to be made to do it "correctly". if you are serious about becoming a pro installer i would think that you have bought books, take classes, learning something about electronics outside of an online forum and i would think that you are learning things there. if you just got into it and dont know a thing, well then my mistake. if you cant take a correction and some criticism then i think you should grow up because you go out to work and you screw up something really simple, you will get your @$$ handed to you.
now you want to be spoon fed? i gave you enough to figure it out. you just have to remember that voltage is a constant. re-read my posts and maybe you will figure it out.
Christopher: There's a big difference between positive criticism and insulting someone. You're comment was unnecessary If your true intentions were to simply correct his mistake and teach him the right way to do it.
its always easier to call someone else stupid when you cant figure it out yourself. your calculation was correct and i think i might have to appologize for making that criticism. i forgot that often in physics there is more than one way to get the answers. my way was using current as my main number rather than voltage. your way is faster.
calculate for current as your variable, and voltage as a constant (12 volts since the power supply in the head unit is usually regulated anyway) is what he wanted you to spot, I believe.
anyway my way is still easier.. just pick the wattage half way between 4 and 8 ohms, since ya already know the power would almost double at half the load.. you can shave a couple watts off to account for the efficiency curve and you've got an answer you can do in 10 seconds in your head
I am looking for a set of component speakers that will hit hard for rap songs but will sound good for rock songs. The two im looking at in my price range are kicker ks series or eclipse. What do you guys reccomend and do different brands work better for rap vs. rock songs?
