two 8'' momos with 220 watts?

[ilikesound]

hello all. i have an alpine mrp-450 something another currently driving a momo 8''. i want to get another 8'', and i was wondering if i should upgrade to a 500.1 to handle the 2ohm load. i just don't know. the mrp pushes 220rms right now, but halving the load might be too small to push either sub correctly. suggestions?

[neomagus00]

if the amp can handle it, halving the load will double the power, yielding awesomosity. find the 2ohm specs for the mrpthingy

[MacLeod]

Im not sure what amp youre talking about but if its not a Class D amp then it wont handle the 2 ohm mono load. Youre better off moving up to the 500.1

[ilikesound]

ok, next question: WHY does halving the ohm load double the power? ive never been able to figure out technically why it does that. its the same power coming outta the amp, isn't it? is there like...some sort of capacitor bypass that's going on in there? so curious!

[MacLeod]

Ohms are a measure of resistance and how it relates to an amp is that resistance is what regulates the output of an amp.

8 ohms is more resistance than 4 ohms so your amp will spit out more power at 4 ohms because it has less resistance fighting back against it. Itll put out even more power at 2 ohms for the same reason. You cant just keep going down tho. The amp will make more power the more the resitance drops but eventually, without enough resistance, it will make more power than it is designed to handle and fry itself.

Also, most amps dont double their power every time you drop the impedance.

[ilikesound]

isn't that contradictory? every amp i have ever seen has "100w into 4ohms, 200w into 2ohms" type of label. even four channels. that to me says, you can theoretically get twice the rated power, so long as your speakers can handle the load.

[MacLeod]

Ratings arent always that accurate - theyre just what they say - ratings. Theyre ballpark figures that give you an idea of what youre getting.

Say Brand X makes an amp thatll make 75 at 4 ohms and 120 at 2 ohms. They rate it at 50 and 100.

Go to Car Audio and Electronics (http://www.caraudiomag.com/) and read some of the test reports on amp. Youll see that the amps they tested arent always dead on with their ratings and virtually none of them double their power with an impedance drop.

Just because you reduce the resistance by half doesnt necessarily mean the amp will them put out twice as much power.