Car Stereos: subs, amplifier manufacturer, two subs

Question
do you know if you can run a dual 4 ohms sub and a regualar 4 ohms sub off the same amp?

Answer
Hi Brian,

You can, but I don't recommend it.  It's generally a good idea to stick with the same subwoofer model if you have multiple subs in the system.

The main problem is that if you have two subs of different impedances (and there's no way to make these two subs the same impedance) then they won't receive the same amount of power from the amplifier.  If you wire the two coils of the DVC sub in series, then it will be an 8-ohm load, and will use power than the 4-ohm sub. If you wire the coils in parallel, then the impedance becomes 2 ohms, and the sub will use more power than the 4-ohm sub.  The output of the two subs will differ, and there's no way to adjust it.

With that said, you're unlikely to damage anything with this setup; provided that each sub is in its own enclosure of the correct volume, neither sub gets more power than its rating, and the combined impedance of the system doesn't fall below the minimum impedance specified by the amplifier manufacturer.

Hope this helps!

Brian