Car Stereos: Wiring up subs., mono amplifier, 4 ohms

Question
Hello,
I have 2 alpine type R's. They are both dual 4 Ohm voice coil, so i wired them in parallel down to 1 Ohm, and have them running off a 1 Ohm stable class D mono amplifier.
I recently got 2 more subs that are 4 Ohms each. if i connected just one of them what would be the best way to connect it. Should i wire it in series with one of the R's? and if i connect both should i run one in series and one in parallel?
thanks!

Answer
Hi Garrett,

To be honest, I wouldn't recommend adding another subwoofer to the system unless you use a different amplifier to run it.  Mixing different speaker types with different impedances on the same mono amplifier is seldom a good idea; and wiring separate subwoofers in series isn't usually recommended either.  

In theory, you could re-wire the voice coils on each of your Type R's in series, so that each became an 8-ohm sub; then wire all three in parallel.  This would result in a 2-ohm final impedance at the amplifier, so it would produce less power than the original 1-ohm configuration; as another side effect, the single 4-ohm sub would get as much power from the amp as both Type R's put together.  That's why mixing different impedances becomes a problem: it's difficult to regulate how much power goes to each individual speaker.

I can't think of any configuration of two 4-ohm DVC subs and one (or two) SVC 4-ohm sub on a single mono amp, that wouldn't result in reduced performance compared to what you have now.  If you'd like to add the additional subs, you really need a second amplifier.

Hope this helps!

Brian