Hey Guys,

It is not as though I have a pressing need to do this, however, I was curious if it is a common practice.

If you have a speaker with a 4 ohm impedance and want more power from that speaker without wiring another 4 ohm speaker in parallel with it, is it common practice for an installer to wire a 4 ohm resistor across it?

The reason I ask is that it seems to be a common problem on a car forum that I belong to. The stock car speakers are 2 ohm. When guys want to upgrade only their speakers, they are finding that they lose power when installing an aftermarket 4 ohm speaker. If this is a common practice, what is the power rating of the resistor that is commonly used? (Watts)

It won't do anything for the power going to the speaker, the extra power goes to the resistor which just heats up. Buy a bigger amp.

"the extra power goes to the resistor which just heats up."

Why in amplifer specifications is the output (RMS) rated higher when a 2 ohm load is connected as opposed to a 4 ohm load? By adding a 4 ohm resistor across a 4 ohm speaker are you not creating a 2 ohm load?

yes, but the speaker does not get the extra power, the resistor does...

^^^ Exactly.

And depending on the kind of amp you have you may lose power by doing that . . .
ie: An amp rated at 80 wrms @ 4 ohm also rated at 120wrms @ 2 ohm.
When dropped down to 2 ohm, the two 4 ohm loads will each receive half of the 120 given to the 2 ohm load (because both 4 ohm loads are required to make the final 2 ohm, they share the power). Therefore, the 4 ohm speaker would only get 60 wrms instead of 80wrms. In addition to this, the amp will be working harder because the load is lower.
End result, amp works harder & heats up quicker, and the speaker gets less power.

A resistor (Unless being used in a complex passive crossover) is never beneficial in wiring a speaker.

That makes sense! Thanks for the replies!

[ September 05, 2004, 06:41 PM: Message edited by: Quest ]