Wall of Silence.

February 21, 2015

With my audio system keeping me company, I drove around for a week and noticed that I was hearing some vibration at the rear of the cab, and traced it to the rear wall. With the new subwoofers the rear wall would vibrate like crazy – I could hear it better from outside the vehicle, the noise coming from the gap between the cab and the front bed wall.  So, that meant continuing with the Dynamat Extreme installation the following weekend.

It was time to turn to the rear end and floor. Already aware of the road noise I could hear from the back wall, that was my first target. It took longer than I thought to get to the back wall since I had to remove the whole rear seat assembly first. With bare metal showing, I first thought that installing the Dynamat here would be so much easier because I didn’t have to reach into door assemblies; however the rear wall was not flat, but had a series of bumps and dips the entire width of the wall, making it an exercise in patience and a lot of roller usage. I also did small sections of the floor, underneath where the front and rear floor mats sit, just to change the floor “frequency” a little bit. The rear floor was easy since I already had the rear seats out, but the front floor meant peeling back the carpet from the foot well end so I didn’t have to pull the seats out again.

Rear seats and rear interior panels removed.
…and the “after install” pic, again going for full coverage.

Once again after re-installing the rear panels and rear seat, I went and rechecked the decibel numbers again at the exact same locations and at roughly the same time of day:

AFTER INSTALL – MEASUREMENT #3

  • Idle before = 49.7-db / after = 45.5-db (-4.2-db drop)
  • 30mph before = 59-db / after = 55.1-db (-3.9-db drop)
  • 60mph before = 72.7-db / after = 69.1-db (-3.6-db drop)

So with the Dynamat on most of the large vertical areas of metal in the cab area I cut down interior noise by 4.2-db at idle and an average of approximately 3.75-db when moving. Maybe one day I’ll tackle the roof for even more noise reduction, but 4.2-db quieter is definitely noticeable; I don’t have to turn the volume on the stereo up as much, and there’s less noise overall when driving. Speaking of the music, I started noticing the lack of clarity on the higher end, and at higher volumes I was lacking a lot of midbass punch. At this point I wanted more.