Installed some Rockford Fosgate R152-S recently in the front, on sale from Crutchfield, with stock base HU. In the dash pods I initially put a heft amount of poly fill - based on a lot of form suggestions. Big mistake! With the volume >12 the mid and low notes were beyond terrible, muffled and sounded like crap at all EQ adjustments. Pulled everything back out and removed the polyfill and 100X better.

I'm wondering though has anyone cut holes in the speaker pods to allow more air in? With the huge difference between with and without the the polyfill, makes me think there isn't enough air for the speaker to work properly.

 

(Oops edit I reread ur post and u have the stock HU) I original had the 730 and when I changed the speakers it sound like crap above 10. I had bad luck with my HU and the original 730 was replaced under warranty at 12 months and the second one lasted about 18 before it too started to lock up. With the stock unit there is not much u can do to make it sound better. The new speakers make it sound clearer but above 10 they popped. I eventually replaced my HU with an aftermarket Alpine. You may have a new HU in ur future if u want it to sound like it should. My final scenario was the aftermarket HU. 14 oz of poly in each sound bar side and 5 oz of poly and a 2in pcv connector port in in each front. Now It sounds like it should have to begin with with. I too was pissed when I got my Jeep with the '368 watt premium sound' and it sounded like a 2004 Corolla.

 

you drilled a 2in hole in the front dash pods?

 

Yes to port the back of the box after putting in aftermarket speakers and HU. The front boxes only have about 1/3 the volume of the overhead sound bar.

 

I have upgraded all of the speakers in my 2016 jeep with Polk Audio speakers and added sound pods on behind the rear seat on the rollbar. I have a Pioneer 8200nex head unit powering the rest. I added PolyFill to all of the boxes. My sound is fantastic. The highs can make you cringe. My bass is a killer as you want it depending on the music that you like. I didn't port or change the pods.

You should consider the sub box from MattK11. I have a 2016 JKU with a 10" box under the passenger seat with a 10"sundowner sub running on a 750 amp Rockford Fosgate mono amp under the steering wheel. My only regret is that I didn't put another one under the drivers seat. I really sounds great and the Bass hits as hard as you want it to. I would put this up against any factory premium audio system out there. I get great bass with the Hard top, soft top or no top. I get people looking around all of the time wondering where the base is coming from.

 

JEALOUS !!
Which model Polks?

 

Just the DB series 6.5's, all component.