Car Stereos: Stock Subwoofer for 2006 Hyundai Sonata, 2006 hyundai sonata, stock speakers

Question
I upgraded my stock radio to a Jensen with a monitor, and the installer said I could not hook up my stock subwoofer to an aftermarket radio.  Is this correct?  Or could it be that a fuse is blown?

Answer
Hi Christopher,

Did your installer integrate the factory amplifier when he put in the new head unit, or did he bypass it?

According to my information, the factory amplifier in your vehicle runs all the speakers, including the subwoofer.  There's no separate output from the head unit to provide a subwoofer signal; the stock amp gets four channels of inputs from the head unit, and uses this to drive the front and rear speakers and the stock sub.  Here's what this means:  if the installer kept the factory amp in the system, and integrated it properly with the new head unit, then the sub should have worked automatically along with the rest of the speakers.

On the other hand, the installer may have bypassed the stock amp.  This means that instead of sending the deck's output to the amp, and keeping the amp to run the speakers, he may have connected the front and rear speaker wires directly to the new head unit.  This means that the factory amplifier doesn't work any more.  You can't use the head unit to drive all the speakers and the subwoofer; if the stock amplifier can't be kept working, then the sub can't be kept working (although you could add a small after-market amplifier to run the sub).

As a general rule of thumb, if I'm keeping the stock speakers in a car, then I'll keep the stock amplifier to run them.  If I'm replacing the speakers, it's best to bypass the amp.  (If you're keeping the amplifier, it's sometimes necessary to use a special adapter to make it work properly with the new head unit).

If you didn't replace any of the speakers, then in my opinion your installer should have integrated the amplifier rather than bypass it, and your subwoofer should be working.  If the speakers are working but the sub isn't, then it's likely that the amplifier has been bypassed.  It's not likely that the problem is a blown fuse, because there's just one fuse for the factory amp, and it run all the speakers, not just the sub.  If the stock amplifier fuse was blown, you wouldn't hear sound from any speaker.

Hope this helps!

Brian