I asked a expert about using car audio for home theatre cause i been seeing alot of threads about this topic.And he replied:
I can see no reason why it would not work just fine. After all, the speaker does not know where it is located!!
Seriously, however, most HT subs have a built-in power amp with volume control. This permits one to adjust the volume of the sub independently of the rest of the speakers. Now--what you can do is to use an AC power supply and the power amp that you used with the sub in the car. Some of these amps have a volume control and you can adjust as needed. Otherwise, your surround amp may have an internal level setting for the sub that will do the same thing.
Most normal HT type sub-woofers are housed in pretty small cabinets. My Polk Audio 12" 150 Watt sub is 17" X 17" X 16" in size. The interior of this cabinet is a bit over 2.5 cubic feet in size. That does not count the amount taken up by the speaker itself, the amp and the tube vent. It is more like 2 cubic feet of air space inside its cabinet. Pretty small as speaker cabinets go. I do not think that car subs are built to much different specs as all the rest of the subs in the world--except for power handling capacity. The roll off frequency is built into the speaker mechanically and should be low enough to do the job regardless. This may be a bit higher in a car sub designed for lots of power, but you still can use it.
I wish I would have written a book about this topic. That way I could reffer to the same explanation exactly the same time and time again. Ther is not a simple one word answer to the question at hand. It is very sophisticated and lengthy.
One of the biggest differences between car subwoofers, home audio or home theater subwoofers is the way it behaves in relation to free air. I am talking about its compliance, Bl, and Qts.
There are other factors such as resistence and power handling (which have been mentioned above).
To make a long story longer... it is just a waste of time, design, and money. There "IS" a reason why engineers make car audio speakers, home audio speakers, and home theater speakers.
Hmmmm.....I not so sure subs are smart enough to know what they are. I would have thought given the sub is in the correct box for it, it will perform just as well in a large space as a small space. Most home plate amps and quite a few normal amps can deal with 4ohm loads, with DVC subs 8ohms is easy to get for the amps that can't deal with 4ohms. Running car amps indoors seems a totally pointless task. For the cost of a power supply that could actually run a big car amp you could buy a nice HT sub and amp. Trying to run one from a battery charger is a recipe for disaster.
Derick Lee of ca&e runs a "5.5" system, where in he pushes 5 car audio subs in custom sealed enclosures. it just depends on the sub and its t/s parameters as mix was alluding to. some subs will work. others won't.
most HT subs need big ported enclosures which is where this comes into play. If a certain speaker is not desinged for this it will lose its control in a large ported box when it was designed for a small sealed enclosure. BL plays a large factor in this in that the flatter the BL of a sub the more likely it can be used in a variety of enclosures and sound good at the same time because the motor is not too powerful for the mass of the sub or underpowered. Now lets take Ascendant audio for example, the avalanche in a HT application is meant to be in a 10-20cu/ft box tuned to 20hz to make it loud enough to fill the biggest of rooms and sound natural. I have a ava in my truck in a 2.5 sealed enclosure and it sounds extremly natural due to the fact that the size of my car is more relavent to the size of the box. If you were to take my 2.5 sealed enclosure and throw it in a ht application it would not have nearly as much authority as it does in my car. Now the reason some can work and some can't is because not all subs can be put in a variety of enclosures and still sound good and have control enough not to rech xmax at very low levels due to overpowering with little power. If you were to take a sub that is designed for a .75cu/ft sealed box with a rms power rating of 300 watts and throw it into a box 10cu ft sealed with 300 watts say good night to that sub, chances are it would be damaged with about 50 watts at continuous listening levels. Hope this helps a little.