Car Stereos: Proper amp, watts rms, sony xplod

Question
Ok so I recently boughtt a 10" Sony xplod 1100 watts and I have a kenwood
800 watt amp so I blew the sub now I just boutght a 12" sony xplod 1200
watts but b4 I blow this one I would like to know if I have the proper amp it's
a 2 channel bridgeable by the way I just whant that sound for a long time not
for a week LOL help!  

Answer
Hi Jordan,

When you're matching a subwoofer with an amplifier, you need to look at the "RMS" power ratings, not the peak ratings.  Peak power ratings are useless for comparing two different products, because there's no particular standard for peak power.  Most manufacturers just use it as a marketing tool.

With the information you gave me, I can make a pretty good guess as to which Kenwood amp and Sony sub you have, and we can compare the RMS power ratings.  My rule of thumb is this:  your amp's RMS power output should be between 50% and 100% of the sub's RMS power rating.  That means if you have a 4-ohm, 200-watt RMS subwoofer, then any amp rated between 100 and 200 watts RMS at 4 ohms should work well.

It sounds like you have a Kenwood KAC-7202 amplifier, or a very similar one.  That amplifier is rated at 150 watts RMS per channel in 4-ohm stereo mode, or 460 watts RMS in bridged mode.

You probably have a Sony XS-L120P5W subwoofer, or a similar model.  That sub's RMS power rating is around 350 watts, but from my experience with Sony subs, I think it's a bit over-rated.  I personally wouldn't use that sub with an amp rated much more than 250 watts at 4 ohms.

You can see that if you're using the amp in bridged mode, then you're going to be giving the sub much more power than it's rated for.  The amplifier can produce 460 watts, and the sub isn't rated to handle more than 350 watts.  You definitely have a very good chance of blowing this sub, too.

In this case, you're probably better off just connecting the sub to one of the two channels, instead of connecting it to the "bridged" terminals.  That way you'll be running the sub on 150 watts, and you're not likely to blow it.  Using just one of the two channels won't harm the amplifier.  In fact, if you want to purchase a second Sony 12" sub and run one sub on each channel, you would probably get decent results and you'll be unlikely to damage the subs.

Make sure you have the subwoofer mounted in a sub box of the recommended size.  If you try to use the sub without a box, or in a box that's the wrong size, the sub's power handling capability might be reduced.

Hope this helps!

Brian