Subwoofer Location

Gentlemen, the problem of placement of subs has been bothering me since I decided to upgrade my factory HK system. I have seen different posts and many pictures of very creative ways to design a bass system. From the JL Stealthbox to using the tire-well as an enclosure to using the rear quaterpanel and fiberglass... I've seen just about everything. This weekend, as an experiment, I connected a PhoenixGold Tantrum 500 amp to the radio and I had an old Kicker Solo 12" around and I played around with placing it in different places in my trunk, here are the results:

directly facing the rear seats: sounds terrible
Near the rear quaterpanel: Sounds excellent when seat is down
behind the rear facing trunk: Also sounds good, when seat is down

But when the seats are up, the bass disappears. Instead of hearing bass as part of the music, it sounds like there's a sub in the trunk trying to kick its way out.

I want those sound waves to enter the cabin cleanly, I want to feel the air moving around my face when the bass hits.

Talking to a local shop, they suggested two 10" free airs in the deck. Something like these pics:



This installation would involve some minor cutting. Has anyone here done this? If so, how was it?