Need to connect a 4ohm Car Audio Sub to a 8ohm Home Audio (500w) amp


New member
Username: Zduchene

Post Number: 1
Registered: Oct-05
I think I need a resistor (4ohm ~100watt). I am having a hard time finding one at my local stores. Does anyone know for sure what I need to do to make this work?

Thanks in advance.

Silver Member
Username: Cory


Post Number: 190
Registered: Jan-05
it would be quite costly and rare to find a resistor like that on a shelf. I would recomend you buy another 4ohm speaker of the same kind and connect it up in parralel or you could try your luck connecting it up to your reciever/amp but check the manual to see if it can handel 4ohm loads

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 6046
Registered: May-04

Connecting two nominal four Ohm impedance loads in parallel will essentially halve the load to two Ohms. That's not the direction you want to go. If you are going to add more speakers, you will need to hook them in series to raise the overall load.

Why don't you try a 20 watt resistor? Since the amp will not be putting out its full rated power at all times, that amount should get you started. If it blows or gets excessively hot, you can begin your search again.

Or, you could not try to force the amplifier into something it doesn't want to do. Adding a load resistor is not the best choice around this situation. Why not buy an 8 Ohm driver and replace the driver you currently have? In the long run, you and the amplifier will be happier.


Silver Member
Username: Nuck

Parkhill, Ontario Canada

Post Number: 143
Registered: Dec-04
You could try the old bright light in the cabinet trick. Series wire a radio shack 12v light in series with the return line and mount it in the cabinet. If you have enought power, the light will illuminate the entire room!(see:Marantz;homemade speakers;bass amp woofers;1977)

Does just as well, and fun for all!

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