Car Subwoofer For Home Theatre


New member
Username: Memize

Post Number: 1
Registered: Sep-04
Hey guys, I recently blew my Home Theater sub and was wondering if I could use a Car Subwoofer in its place. I realize that Car Subs are 4 Ohms and Home Subwoofers are 8 Ohms but I have seen Car Subs that can be wired to 8 Ohms. Could I just wire a Car Subwoofer to 8 ohms and then buy a car amp and solder the points on the amp to work with an electrical outlet in my home? Has anyone else tried this or have a better idea? Thanks In Advance :-)

Bronze Member
Username: Ben805

Post Number: 17
Registered: Aug-04
if your sub is 4ohm, then you'll need to get another identical 4ohm sub to wire them in series to get to 8ohm. I dont' know what receiver you're using so check the specification, if it's stable down to 4ohm then you'll be fine, I know most Onkyo and H/K stuff are fine with 4ohm.

New member
Username: Memize

Post Number: 2
Registered: Sep-04
now that I think about it, does the ohm rating even mater? The only way the subwoofer would be connected through my reciever is through the mono subwoofer rca jack on the back of my reciever. The amp would be powering it, so would it really matter what ohm the subs would be?

Unregistered guest
It does matter what ohms you want. A similar problem happen to me. I have a Sony home theatre system that max output is 285 watts. My old subwoofer blew out and it was a 4ohms speaker. Now my amp sends out an 8ohms of power. The specs on my speakers was 40 watts normal RMS power and 160 watts High peak (Range 40-160) The best car audio speaker you can get for an Home audio is Rockford Fosgate. The specs on the speaker I bought was 150-300 RMS power. Which was perfect for my reciever. The only thing was that it was an 4 ohms speaker. The sound was great, but the speaker was not using all the power it should. The next day I exchanged the speaker for an 8 ohms. Big diffrence when it comes to bass. The bass sounded more deep, clear, boom sound. So if your amp outputs 8ohms then get an 8ohms speaker. It does make a diffrence.

Marco Kuipers
Unregistered guest

1. The Ohms is the resistance of a speaker. If the resistance of the speaker is less than the AMP can handle, its like running too fast down a hill, it will fallover (read overheat, sound bad, perhaps damage).

2. Replacing a subwoofer is very tricky as the cabinet size is a close match with the speaker. Find a speaker that requires the size closest to what you have (if its ported, you still probably have to redesign the port).

3. Measure the ohm on your 'broken' subwoofer if the coil is not damaged (its still measurable) if it is on your meter about 3, than the 'normal' resistance is 4, if 5 then 6, if 7 then 8. So you know that amp can drive this. If your current one is 8ohm (only if driven with a normal amp, most build in amps are driving 4ohm speakers), find either a single voice coil of 8ohm, or a dual voice coil (DVC 2x4ohm), to run in series to create 8ohm. If you need 4ohm, run a SVC of 4 ohm or a DVC of 2x8ohm in parallel, to create 4ohm.

Hope the above is clear.

Marco from OZ.
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