5x7 boxes/ home amp

I have some 5x7 infinities that don't fit my car and i can't sell, so I was wondering how I can figure out how much volume i need for them if I build a couple boxes for them. Also, since the speakers are rated at 4 ohms, what happens if I power them with an 8 ohm reciever meant for home use. Will it damage either the amp or the speakers? Do i just have to be careful and not turn it up too much because it will be easier to blow the speakers cause the amp is meant for higher resistance speakers? Thanks for any input.

How many do you have?  If you have four, then you can series-wire two together to make 8 ohms, and do the same for the other two.  5 X 7's are made to be infinitely baffled, such as their use in a car door or rear parcel shelf, so you won't find a formula to figure volume for those.  Just don't make the box too small.  Try maybe a cabinet for each pair about 20" X 8" X 12" (I'm just looking at a pair of old speakers I have here, that is their size).  Do not connect them to your receiver at 4 ohms!  Volume is not the issue with ohm load on an amplifier.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

so what is the issue? What would happen if I connected the 4 ohm speakers to the 8 ohm receiver? Which would be damaged? Does it go the other way, hooking 8 ohm speakers to a 4 ohm amp? I'm just trying to get som clarification. Thanks

An amplifier will try to send current depending on the ohm load presented to it.  Most home receivers are built to take an 8 ohm load.  Presenting the amp with a 4 ohm load means the amp will respond by sending much more current through its circuitry to provide the power asked of it.  The problem, then, with too low an ohm load is with the amplifier, not the speaker.  It is the amp that will be abused.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

OK, i get that, but what happens if 8 ohm speakers are hooked up to a 4 ohm amp, is it the speakers that take the abuse in that case?

No abuse to anyone.  A lighter load for the amp, and less power to the speakers.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

hmm, ok. I guess I'll have to get another pair of speakers or something, so I can wire my 5x7's. Except i won't wanna buy anymore. Hmmm. I;'ll figure somethin out. Thanks. I want to use them as speakers for my computer.

Another question, aren't the voice coils in speakers designed to have the flow of electricity go one direction? I just don't understand how wiring them in series works. I get the actual wiring and how to do it, but not what's really going on. Thanks