| Soundproofing
Although the Defender is a hard backed commercial vehicle and essentially
should be pretty rough and ready inside, we are too used to normal
cars and also given that most of our defender driving is done in
town and on main roads we decided that we would try and make it
as comfortable inside as possible. The first step in this process
was to soundproof the car.
The process is quite simple: Any large flat panels of metal that
vibrate and create a booming noise should have a sheet of dense
rubber glued onto them to create solidity in the panel. The next
step is to attach a fibrous felt material to soak up any remaining
echo.
We picked up a full truck cab sound proofing kit from SRS at Billing.
This included all the relevant material to cover the front internal
bulkhead, the seat boxes, the tunnel top, the floor and the toe
boards. Also included was a full under bonnet sound proof kit and
inner door rubber sound proofing.
Although quite expensive at £150 GBP it was pretty convincing
as some sections were lead lined to cut out low frequency vibrations,
like on the tunnel top and bulkhead. It seemed to be well developed
and quite complete.
Once this was fitted the rear load bay still had to be soundproofed
and this was done as described above with rubber and felt. We were
lucky enough to find a factory in our local area which used to make
specifically car soundproofing material. Unfortunately it shut down
about a year ago. Never mind though, as I was able to make contact
with a previous employee who still has access to the materials.
The materials that they manufactured were used to make by car makers
like Opel and ford.
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| Bonnet before |
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Bonnet after |
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Footwell before |
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Seatbox before |
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| Seatboxes after |
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Toeboard S.Proof |
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Rubber Material |
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Rear Bulkhead after |
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| Loadbay before |
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Hard Back Rubber |
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Hard Back Flock |
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Rear Seatbox rubber |
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| Finished seatbox |
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Rubber material
The rubber sheets that we sourced were far better than anything
that we had previously used. Not only were the sheets massive, they
were also heat moldable. With the use of a heat gun we were able
to mold the sheet to the exact shape of the panel that it was being
attached to. Not only that, they were also pre-glued on the back
- So as they get heated and bent to shape, the glue melts and sticks
itself to the panel.
Felt/Flock material
The other material is the felt flock material. This is a reconstituted
cotton-felt material which is about 1 inch thick and very dense.
Not only that, it is impregnated with phenolic resin. Again it can
be heated and molded to almost any shape. This material cuts out
any echoes and in combination with the rubber makes the appreciably
quieter.
By the end of this process we had sound proofed the:
- Underbonnet
- Front inner bulkhead
- Tunnel top
- Front floor
- Seat boxes
- Inside the front doors
- Front and back of the rear bulkhead (behind the seats)
- Rear upper side panels
- Lower rear side panels
- Rear seat boxes (top surface and side upright)
With this done the inside of the car looked like there had been
a rubber explosion and it was very dark. However the elimination
of road noise and engine noise was extremely impressive. Yes you
can still hear the engine, but to a much lesser extent, and with
the TD5's music, I'm glad it's still audible. Road noise has been
cut dramatically as has the booming vibration that used to come
from the rear panels.
Next Step Carpeting..........
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