8 ohm subwoofers ... im confused?

Question

I purchased two 15 inch Q-power (infinity) subwoofers they run at 8 ohms and are 400 watts rms and 800 watt peak each all the amp I look at only give me the 4 ohm rating what would the what would the 4 ohm rms need to be to power a 400 watt rms at 8 ohm?? i hope my question makes sence...

I wire the terminal together as stated below and used an ohm meter and to my utter amazment it it reads at 4 ohms now that is amazing... what is the science behind this??

Answer 1

Here is the science mathmatically:

Subs in parallel, where Z is the total impedance (ohms) and sub# is each sub (or coil in a multicoiled sub):

Z = 1 / (1/sub1 + 1/sub2 + 1/sub3 + ...) as many as you have.


Go here:

http://spkrbox1.spaces.live.com

Answer 2

If you intend to use a 4 Ohm Output Terminal on your Amplifier, you can connect both 8 Ohm speakers together (+ Terminal to + Terminal, and - Terminal to - Terminal) and produce a 4 Ohm load for the Amplifier. That arrangement can safely handle a maximum of 400 + 400 = 800 Watts RMS or 1600 Watts Peak.
As long as your amplifier is less than that you will not destroy the speakers. Using power like that will probably drive you deaf in short order if you are close by the sound system.

Answer 3

If you bridge your amp to mono and run two 8-ohm speakers into it, it will read the load as 4-ohm. Happy thumping!

Answer 4

if your amp is 8 ohm out put , and your speakers are only four, your anp will not have to work so hard to drive them.

An 8 ohm- L- pad between amp and each speaker may be a solution