Will 8ohms output work with a 4ohms speaker?

Question

im installing a new subwoofer on my home theater system and the home theater systems subwoofer ouput is like 8ohms i think and the new subwoofer im buying is 4ohms, its a memphis 15" 500watt and no im not wireing it directly to the home theater im running it through an amp and the amp does all of the ohms for speakers, 2ohms, 4ohms, and 8ohms

so will it work?

Answer 1

Well, use the 8 ohm tap! You will just get some efficiency loss with a mismatch. It's only a big deal if your a connoisseur.  

Answer 2

It will probably work, but it can damage your equipment. The reason being is that running an output resistance of 8ohms to an amplifier crossed over for 4ohms has less resistance through the amp. Thus, the amp could and probably will start over-drawling power from the stereo's subwoofer channel. Which can damage the subwoofer channel in the stereo and the stereo's own built-in amplifiers (even in subwoofer applications with built-in amps ( in the speaker box). To tell if damage is occuring to the stereo (over time) observe the following:

When you press the power button to switch the system off, the power LED should switch off instantly. If over-drawling of power damage is occuring the LED light will slowly fade out. The longer it takes for that light to turn out the more damage that has been done, until it eventually frys out completely and no longer functions.