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Old 05-04-2019, 11:12 PM   #1
Junior Member
Brand: Thor Motor Coach
Model: 28i
State: Washington
Posts: 4
THOR #15170
Sound Deadoning 28i Coach

We took our coach on its first road trip two weeks ago, ~300 highway miles. The coach handled great. However, cabin noise was a huge issue. First issue 10 miles into the trip was the side entry door squeaking so loud I had to pull over. Upon examination the door latch and door latch post were metal on metal with marks from rubbing. To solve the issue temporarily I wrapped the latch post with strips of paper towel and closed the door. With that issue solved we proceeded down the road towards our destination.

The next issue was extreme cabin noise from the V10, road noise and tires. We literally had to yell at each other to talk. Compounding the issue, the stereo sound like...shit. On top of these issues, my feet were sweating from the floor heat.

The following post shows how we solved the issues, that Thor should have.

This project took about eight hours, not including waiting for Amazon to deliver everything.

The first thing I did was remove the two captains chairs. Then I removed the plastic trim, black floor mat and dog house.

I then cleaned all metal surfaces to prepare for sound deadening the floor. I then proceeded to install three layers of sound deadening materials.
  • Kilmat 80 mil 36 sqft Car Sound Deadening
  • Noico Green 170 mil 18sgft * w
  • Uxcell Wave Studio Sound Acoustic Absorbing Heatproof Sound Foam Deadener 19.7x197

This part went pretty fast. If I had to do it again though I would hold back the top two layers about 1” from edges to allow the trim to go back into place easier.

I then attacked the Doghouse which had 1/8 heat shield covering it with 3/4 inch Design Engineering 050130 Boom Mat Under-Hood Thermal Acoustic Lining. I tapped the seams and edges with Design Engineering 010408 Cool-Tape Self-Adhesive Heat Reflective Tap.

Next up was removing the driver and passenger door trim. I then insulated the inside of the doors with the Kilmat followed by the Noico Green. I replaced the factory speakers with Cerwin Vega 6x9’s mounted inside XTC VXT69 speaker baffles. I had to modify these to be 2.5 inches deep so the windows would no hit them. I then put Roadkill RKFR69 foam around the speakers to get a tight seal against the door trim. I also put uxcell Wave Studio Sound Acoustic foam on the door that is covered by the factory trim.

I then reassembled the coach. The end project looks great. Unfortunately I cannot post all the pics due to forum limits.

Today, we took the coach out on the highway. I am happy to report we were able to talk normally and we could hear the radio without having to crank it. The engine and road noise are significantly reduced. The heat from the floor is pretty much gone. Though the Axxera radios built in EQ sucks. We simply cannot get it to sound good. I suspect we need a sub and two speakers on the pillars to get it to sound better, but that will require a new stereo. That project will have to wait until next year.

The next project is fixing the door latch rattle issue with something other than paper towel strips.
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knotpc is offline   Reply With Quote
Old 05-04-2019, 11:24 PM   #2
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Brand: Thor Motor Coach
Model: Axis 24.1 Windjammer
State: Illinois
Posts: 1,179
THOR #7074
Welcome to Thor! & Welcome to the Forum!!
Rev. Jeffrey 2017 Thor Axis 24.1 E450 Windjammer.
Silver Safe-T-Plus Steering Control
SSF-106-40 SumoSprings Solo Front Bump Stop SSR-107-47 SumoSprings Rear Bump Stop
Hellwig 7718 Front Sway Bar & 7180 Rear Sway Bar
Koni FSD Front Shocks 8805-1042 / Koni FSD Rear Shocks 8805-1043
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Old 05-05-2019, 01:44 AM   #3
Senior Member
Brand: Thor Motor Coach
Model: Palazzo 33.2
State: California
Posts: 251
THOR #12839
Great job! We might have enjoyed our gas A longer if we'd done that! (The factory should on ever gas C & A). Next worst thing was the ride. I was considering a Kelderman Air Suspension kit...
2018 Palazzo 33.2
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Old 05-05-2019, 02:08 AM   #4
Senior Member
Brand: Thor Motor Coach
Model: SOB 2014 Meridian 36M
State: Washington
Posts: 981
THOR #7205
You went a bit further than I did on mine. I finished floors & doghouse a couple weeks ago.
Pat & Becky & now Katie
Wenatchee, WA
99dart is offline   Reply With Quote

class c, class c 28i, sound deadening

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