i'm checking out subs and amps on the net and i see that some amps say they have like 775 wattsX1 and then with 4 ohms equals 200 watts by 2 and some other stuff...what does this all mean? when hooking up amps and subs in your car, what is the normal hook up? what should i be looking for when i want to buy an amp and subs?

i'm looking for say a good 300 to 600 watt sub and a little more for the amp ( 500 to 1000)....2 ways....does manufacturer also play a role? if so what would u say is best out there? kenwood, rockford?

a little weak on sound...someone give me some info...thanks

 

Yeah the ohms will affect the watts you are getting out of your amp, depending on how effecient it is. A rough estimate would be a double in watts for a half drop in impedance. This isn't exactly true but should help you understand the concept, so if your amp is 75x2 at 4 ohms it shoud be about 150x2 at a 2ohms. However the lower the impedance the harder the amp works and the more heat you will get, and heat is what kills amps. The main thing you need to do is insure your amp is stable to whatever impedance you are going to run it to. Check out JL audio.com, they have a lot of good info on there. As for what brand everyone has there favorites, I have 2 kicker ZR 240s in my trunk, but people will argue for several different brands. But the bottom line is it definitely matters what brand you select, you get what you pay for.

 

It's all about ohm's law. An amplifier generally has a maximum amount of voltage that it can provide. At different loads (ohms) this equals different power levels. V=iR and P=iV So if we do a little algebra we can see that P=V^2/R. V is voltage,i is the current the amp can deliver and R is the load in ohms, P is the power. So if a given amp can deliver 28.282V of voltage into a 4 ohm load you get 200W. 200W=28.282V^2/4ohms. Into a 2 ohm load you get 400W. 400W=28.282V^2/2ohms. At 1 ohm you would get 800W.

Generally this it doesn't work quite like this as the transistors in the amp have a maximum current they can provide. They also become less efficient as they heat up. For example to get 800W into 1 ohm the amp has to be able to push 28.282A of current. If the transistors can't deliver that much current then the amp will not have a power rating of 800W into 1 ohm. It may only be 600W. It's also possible that the amp will not be stable into 1 ohm.

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