i just repaired a pair of 15" cerwin vega subs and a friend of mine gave me a 15" car box...and i was wondering if i could hook up the house speaker to my car amp... i know the house speaker is on 8 ohms and the car stereo is on 4 ohms but i don't know what this means...i'm kinda on a stuck not to good with stereos

 

Going up in speaker impedance (ohms) won't kill anything, generally. The speakers just won't be as loud or as effecient as lower impedance speakers.

 

no destortion or anything?

 

ohms measure the resistence, it should only affect power, not the actualy sound quality to my understanding. is the sub the only thing being put in?

 

yeah a have some old cerwin vega house speakers that i just put new rubber on but the box is fucked so i wanted try hooking them or i mean one of them in my car...

 

its a single voice coil, right? im pretty sure itll be starved and not be worth the effort, but give it a try, start with low volume as always

 

The sound quality will be the same.
The impedence just means that the speaker is resisting more or less power.

8+ohm speakers are meant to be run in parallel (with another 8 ohm speaker inline) which would make their combined resistance only 4 ohms....which is a safe level to have an amp, but I have always run mine at 2ohms and by the time they blow (years) its time to get new stuff anyway.
This CW 15 you got probably ran inline with to another mid/ tweeter and that is why it is 8 ohm.

So, the sound quality isn't effected. Your amp will be happy and cool because it is only pushing 1/2 the power it could. Follow?

 

Is the "car amp" the main deck or a seperate power amp? As far as the ohms thingy goes, your amp will put out X amount of power (per side or total) at 4 ohms. If you put a 4 ohm load on the amp you will get max power (another story we won't get into) out of the amp. If you put an 8 ohm load on it let's say 2/3rds of its total. Wattage is very misleading as far as volume is concerned (another story), let's just say the more you have the better sound you have. It takes more power to reproduce low end than high end and the more power you have (as long as it is clean power) the fuller and tighter and cleaner your system will sound (all things being equall as far as how the speakers are rated per sensitivity for wattage and so on and so forth). Basically, you're not going to hurt anything, might sound floppy on the low end if you push the system. If the speakers are rated at 8 ohms each you can run them one of several ways depending on your setup. If it is a stereo amp (deck unit) and you can fade front/rear then wire them to the rear, one to the left output, the other to the right. If it is a power amp, most of the time you can run them in either stereo or mono (bridged). If you can run your power amp mono to just push the subs (subs really don't do much in stereo) then wire the 2 speakers in parallel to get a 4 ohm load if the amp wil handle that load. You can't get a two ohm load out of two 8 ohm speakers, only 4 or 16. If the speakers are truely subs then just running them off the L/R outputs of your "deck" or power amp without correct cross-over points somehow wired into it could be pointless. You sending a full range signal into a speaker that can only reproduce sounds you feel, not hear so to speak. Worse case senario, a lot of work and it sounds "fair" but you won't hurt anything.