Car audio: Impedance

[sxtasy]

I have two, four ohm Alpine subwoofers and an Alpine amplifier. How do I hook these subs up to get 2ohms out of my mono block amplifier?

[KoukiS14]

Parallel

http://akamaipix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/2SVC_4-ohm_mono.jpg

[Grogador]

In parallel...

Amp's (+) to sub1's (+) to sub2's (+)
Amp's (-) to sub1's (-) to sub2's (-)

...assuming each sub has a single 4-ohm coil, you'll end up with 2 ohms.

http://www.soundkraft.com/Subwoofer_Wiring.htm

[///LOUD LOAD\\\]

These guys have it covered. But good question are they single or dual voice coil? iF thay are dual 4ohm then you can not make a 2ohm load, only 1ohm in parallel and 4ohm wired series/ parallel.

[Graham_A_M]

^ Yes but it is possible to use just one coil per sub.

So many people with DVC subs think they HAVE to use both coils, and thats not the case most times.

[bundi]

hmm never thought of it that way...

I would suspect the performance of running only one of the voicecoils to be cut somewhere near half though... In which case, you are better off running one sub and not under-driving two.

[Graham_A_M]

^ The vast majority of the subs dont have issues with running the full RMS into one coil. Most times the issues lie with maxing the subs suspension limitations. Obviously that isn't a VC related problem at all.

Some subs do have thermal limitations thus limiting the amount of power allocated for each coil, but with most it isn't a thermal issue at all, just an "Xsus" issue, which means the subs mechanical suspension limitations.
Typically in the off-chance a sub does have limits to how much power to put to each coil: its listed right in the spec sheet of the sub, as to how many watts should be allocated to each coil.

[sxtasy]

thanks for the info guys.

Each subwoofer I have is in its own separate enclosure. Now can I run parallel from the terminal on the sub enclosure or does it HAVE to run from the sub?

[Graham_A_M]

Either or, just so long as you end up with the two ohms. You can do it at each of the terminals, or have speaker wires coming from EACH terminal, and just feed both wires into the speaker outputs of the amp. Doing so you'd obviously have dual + for each sub, and dual - for each sub as well, and therefore two wires per channel output.

Hopefully that answers your question. :dunno: