paid too much for speakers, tech question

[JAFO]

First here is a link to a parallel & series calculator: http://www.the12volt.com/caraudio/boxcalcs.asp#par

Now household stereo systems generally use 8 ohm speakers and car audio generally uses 4 ohm speakers (there are some exceptions, dual voice coil for instance, but this is in general).

Parallel Circuit: All positive leads of two or more speakers connected together and all negative leads connected together.

If you take two 8 ohm speakers and connect them together in parallel your load on the amplifier will be 4 ohms. The resistance is cut in half. Similarly if two 4 ohms speakers are wired in parallel the resistance will equal 2 ohms.

Series Circuit: Connecting the positive speaker output of an amplifier channel to the positive terminal of speaker # 1 , connecting the negative terminal of # 1 to the positive terminal of speaker # 2, and the negative terminal of # 2 to the negative output of the same amplifier channel is a series connection.

If you take two 8 ohm speakers and connect them together in series your load on the amplifier will be 16 ohms of resistance. Two 4 ohm speakers would give 8 ohms in resistance. In a series the resistance is doubled.

So to answer your question, yes if you have a 4 ohm speaker and connect a 4 ohm resistor in series the result will be a 8 ohm load on the amplifier. Now if you mix speakers who's resistance is not the same use the calculator above and you will see that a 8 ohm and a 4 ohm speaker connected in parallel would have a 2.666 ohm load. In Series it would give a 12 ohm load.

As far as what your amplifier can handle read the owners manual or look for specific information about that model on the Internet. If you deside to go with a lower resistance than stock your amp may run hot leading to clipping - amp gets too hot and temporarely turns off to avoid damage. If your amps are so hot that you can't touch it there is a problem.