Final Tuning Problem

[jsampsell 10+ year member]

Ok, I've posted a few times on here as I've installed everything in my system. Here's what I've got:

2007 Ford Five Hundred Limited

Pioneer AVH-P4200DVD with HD and Bluetooth modules

Infinity Reference 5350a 5 channel amp (50RMS x 4 at 4 ohms and 300RMS x 1 at 2 ohms)

JL Audio TR570-CXi 3-way full range 5x7s for four doors

2x Eclipse 86080.4 8" subs in the rear deck

I've installed 100 square feet of B-Quiet Extreme into the car (doors, roof, floor, rear deck and trunk). I've got everything installed and tuned perfectly. The problem is that when I make my tuning adjustments the car is either off or idling and when I go to work (an hour drive averaging around 55mph) the interior noise levels drown out the lower end of the frequency spectrum. In order to get it to sound the way I like it I have to pump the volume up to levels that I really don't care to listen at.

I know I don't have a Lexus or whatever other cars are known for how quiet they are from the factory but after putting the sound deadener in I kind of expected a little better results.

I first wanted to know what the sound level difference was between idle and 80mph so I got a decibel meter and this is what I found using a weighting of A.

Idle no air: 58 dB

35mph: 62 dB

45mph: 68 dB

55mph: 70 dB

70mph: 78 dB

75mph: 80 dB

I didn't think about checking this before I installed the sound deadener unfortunately so I don't know how much the deadener improved it.

The more I think about it, though, the more I think that the sound level only is one part of the problem. The other part is the frequencies that the road noise generates. Seeing as how it seems to overpower the lower frequencies it would make sense that it is somewhere between 20Hz and 125Hz. It definitely affects the sub which is crossed at ~80Hz but it also affects some of the midbass frequencies as well so that's why I gave it that range.

Do any of you have any ideas about what I can do to at least minimize it if not do away with it altogether? I can't go out and get a different car, much less one that has very low interior noise from the factory, but I really would like to figure out something to help with this.

Criticisms and wisecracks are expected and welcomed but suggestions would be greatly appreciated.

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[PrestigeSounds 10+ year member]

you basically covered it from the deadening aspect....what is the thickness of the deadening material? where do you listen at and where do you need to crank it to for it to sound good?

 

[jsampsell 10+ year member]

Here's what the B-Quiet website says:

B-Quiet® Extreme is a 1.15mm (45mil) thick composite mat which consists of rubberized asphalt with an aluminum constraining layer. When the paper backing is removed the supercharged adhesive surface forms an incredible bond to ensure optimum deadening performance.

I only did one layer so I know that it would work better if it were thicker but from everything I read online before doing the project I didn't think I'd need it if I was doing pretty much the entire car. The one place I didn't do was the firewall. Maybe I need to do that.

I've got the gain on the front and rear fairly low to offset hiss and the HU is a 1-40 range. I tune it anywhere from 9-10 and I have to turn it up to 13-14 to really heat the full range again.