What size amplifier for two kenwood 10 subwoofers?

Answer 1

That will depend on the subs power rating, and how they're wired. Since I don't know which model subs you have, I can only give you an example and not a definite answer.

Let's assume that your subs are rated at 100W RMS @ 4 ohms.

If you hook them up in series, you will then need an amp capable of delivering a minimum of 200W RMS @ 8 ohms. (more would be better, say 250W @ 8 ohms)

If you run those same two subs in parallel, you will then need an amp capable of delivering a minimum of 200W RMS @ 2 ohms. (again 250W would be better)

Hope this helps!

The wattage of the speakers MUST be more than the amp. Otherwise you can potentially blow the speakers.

The impedance of the speaker MUST match or be more than the amp Otherwise you can potentially blow the speakers.

Ideally you want more than enough power in amp and speakers than your highest listening volume. An over driven amp introduces distortion.

If speakers are wired in series then there is more resistance you half the wattage but double the impedance. So 2x100w 4ohm speakers in series are 100w at 8ohm.

If the speakers are wired in parallel then there is less resistance you get double wattage but half the impedance. 2x100w 4ohm speakers are now 200w into 2ohm

Most car amps are 4ohm (home hifi usually 4 or 8 ohm) therefore to add 2 10" subs you would need 2x 8ohm and wire them in parallel to half the impedance to 4ohm. Many car sub woofers are dual 4ohm voice coil. This means you can wire a single speaker unit as 2ohm, 4ohm or 8ohm and this then means you can run sets in parallel or series as you see fit.

heathcnc here again:

I made the assumption of car audio and didn't consider the home audio/theatre possibility. I apologize.

I completely agree with these two statements as applied to a home audio/theatre situation.

"The wattage of the speakers MUST be more than the amp. Otherwise you can potentially blow the speakers."

"The impedance of the speaker MUST match or be more than the amp Otherwise you can potentially blow the speakers."

However in car audio, the amplifiers are of a different class and are far more flexible and user-configurable. This is why I always recommend running an amp that is more powerful than the speaker it is driving. That way you can set that amps gain lower than full power(an option unavailable to the user on home equipment). When configured correctly like this there is very little chance of harming your speakers.