Car Stereos: Ohm help!!!, ohm voice coils, memphis subs

Question
QUESTION: Hi, I was hoping you can give me advice on how to wire a box wi.th four ten inch subs. Two of them are bazooka cs-1004, single 4 ohm voice coils, and the other two are memphis 15-pr104d. I will be hooking them up to a pioneer gm-5500t. I have general knowledge with series and parallel wiring, but this is justvconfusing the hell out of me please help!!!! I thank you very much in advance for any advice you can give me, thanks again!!!

ANSWER: Hi Jesse,

Your amplifier supports 2x2ohm, 2x4ohm, or 1x4ohm according to http://www.pioneerelectronics.com/PUSA/Car/Amplifiers/GM+Series/GM-5500T

Your bazookas have single 4ohm coils, and your memphis have dual 4ohm coils.

This is a bit of a problem because the impedances are all mismatched.

What I would suggest is to wire the 2 bazookas in parallel on one channel of the amp, providing 2 ohms of load to that channel.

Then, wire the voice coils in the Memphis subwoofers in parallel, and then wire them in series on the other channel, providing 4ohms.

Unfortunately, this isn't ideal, but that's what you're faced with with these speakers.

Justin

---------- FOLLOW-UP ----------

QUESTION: Hi, I greatly appreciate your advice, however while awaiting your reply I had to make a decision as I was doing this for a friend. The way I wired it, I'm not sure if it was a good idea or bad, I ran the memphis coils in series for an 8 ohm load each to each channel, then ran the bazookas in series off of bridged mode like a tri mode amp. I haven't listened to it or monitored it all, but I thought this to be the safest way to run it without risk of blowing anything. Do you have any idea of a final impedence that its running at (amp)? I was thinking of it as running 3 subs at 8 ohms, how does this set up pan out mathematically? Thanks again in advance, any help or advice is greatly appreciated!!!

Answer
So you're saying you have the Memphis subs in series on each channel, and then the bazookas in series bridge across both channels?

This means both channels are seeing 8ohms from a memphis, and half of the 8 ohm impedance provided by the series wired Bazookas.  So they're seeing 8ohms and 4ohms in parallel.  Using Ohm's law, this means each channel is seeing 1/((1/8)+(1/4)) = 2.6ohms.  This means the amp will safely run this just fine.

Justin