Hi, I just bought a 2005 mazda 3 HB. I was asking myself If i would be able to install a subwoofer to the original deck or I would have to install a aftermarket deck?

need to know a.s.a.p.

Thanks, hope someone can help me with this.

(its my first time owning a mazda!!)

 

use a line level converter to send audio to the amp. Make sure the converter or the amp compensates for the 1/2 battery voltage that is the bias of the speaker outputs.
One downside is the bass drops as you crank it up, calles auto loudness I think, and only is needed for the factory speakers. Sadly there is no pre-amp output, and I cracked my headunit open and I don't see any easy attachment to make a pre-amp output either.