what direction are you firing your sub? i understand its a trunk plus only has center hole for air to flow thru cabin. What would be loudest? my plans were to have sub pushed back port and sub firing forward.

i see alot of JL guys here,not leaning torwards sq. more of a high 49's class daily. Any advice would help

 

I have done sub facing down, facing up,facing forward and also facing backward. To tell you the truth it doesn't make much of a difference. I always thought facing the sub backward would be louder because the wave would bounce off the rear wall and come to the front of the car

 

When I had a truck my JL 13.5 W6 sounded louder facing up, but now it's in my TL. I heard for cars you should face it towards the rear. Could be wrong, but sounds good to me.

 

Ive done everything in tl but infinite baffle is something special. For the first time i find myself sitting in the car and just enjoying the music. Pure SQ, plays every note as intended.

 

Firing inside the cabin

Seal off the trunk

 

I think removing the stock sub so the bass can get from the trunk to cabin easier will have the biggest impact. I went further and cut 3 holes in the top of the trunk carpet/board to match the 3 holes in the metal shelf and then used seal and peel to isolate the rear speakers amd essentially make a sealed bass port from trunk to the cabin. Bass from the sub in the trunk comes straight up through that and right into the cabin I barely need to turn up the gain on my amp.
If you think about it tnormally here's a lot of wattage wasted on trying to produce enough bass to get through the enclosed trunk to the cabin.

 

Web search for corner gain. It made a 4db difference in my TL.

 

My 12" dvc sounds louder and more balanced when it is facing the rear compared to facing towards the back seat. For some reason the bass sounded unbalance when I had the box sitting on the driver side facing the front. So my vote is face the sub towards to rear. And I had the 8" sub and the carpet underneath the rear deck removed too. I did something smiliar to Gregerst. I used some Second Skin pro to seal the rear speakers to from a small baffle for the rear speakers, which is the source of my mid bass (set x-over @ 90Hz up front; 70 Hz for rear speakers; 70Hz low pass for sub), works well!

 

That's not a bad idea. Back when I had a box I found that facing them forward up against the rear seats sounded more snappy and clean but it lost a bunch of low end. Then I half assed sealed them to the cabin and got the low end back.

Now with the IB setup the trunk is very sealed off from the cabin and mine are flat within 1.5db down to 18hz and require very little power.

The TL seats will pass bass through but they will start blocking frequencies above 50hz. Mine fire through the skipass but with the armrest up it filters the higher frequencies but I still get most of the low bass. There is a difference but not that bad. I can have passengers back there with the armrest up with no issues.

The big improvement I've found is by making it easier to get bass into the cabin, trunk and deck rattles can be reduced.

 

^^ I'm about to go this route. Got a 15" sub and new alpine amp coming in the mail. I keep hearing how great IB is so I'm looking forward to trying it.