Investigating Sound Proofing

[tully]

i have a 2007 TCH. and a 97 es300 lexus. The lexus is quieter which was to be expected.

So far i have noticed that the Lexus has a fat rubber mat in the trunk below the regular mat. I have also taken a professional Sound Level Meter and poked around a bit.

Center console, I get 65 DBA at 80km. Rear Floor 65 DBA,
Reat Seats 65 DBA. Front Floor 67-75 DBA ??? .. hard to measure there.
But, on the vertical surface below the seat cushion the noise increases
to around 73 DBA. The other area is the whole area that is carved out
on the front doors for storage. There i noticed levels from 70-75 DBA.

The floor areas and the trunk i will try some commercial underlay. That
is a mouse fur covered very high density foam. Reasonably thin and
similar to the mat that Lexus uses..

For the doors probably Dynamat or something similiar...

Stay tuned...

[AML]

There was a member here that added sound deadening material (more for stereo acoustic performance) in his Camry using some interesting (although "regular" foam materials). Try to find that thread - it might give you some inspiration.

Depending on how long we keep this Camry I might do similar. I'm not looking to spend Dynamat money on it, but if I can use other cheaper materials that will quiet it down close enough I'll go for it.

[ukrkoz]

hey, while you driving around with decibel meter in your lap, maybe you'll figure out how to sound proof the windows? mine has super annoying hissing noise coming from both front windows.

otherwise, nothing will deafen noise due vibration caused by stiff rubber tires, over inflation, mediocre suspension, and poor road condition. it goes through the metal. good luck.

[tully]

Just finished with the passenger door, the results are impressive. Took about one hour.
Will post some pictures when I do the driver's side. Total cost per door around 40.00

[AML]

Please do, I'm very curious!

[tully]

i added some commercial underlay (3/8" thick), there is a sample in the bottom
of the picture, the DB meter indicated there was noise coming from that area

after

[tully]

Lastly i added some inexpensive sound deadening product. I got mine from Lordco
here in canada. They sell PF 350 which is made by Pro Form. This is a butyl based
rubber bonded to thick aluminum and is self adhesive. I did not do the WHOLE door
panel, only about 75% of it. The front doors now have that thud quality....
I did one door first and took it on a test drive before doing the 2nd door. Total
sound reduction is around 2-5 DB depending on the type of road noise. If the road
is lightly worn it works very well, very coarse pavement not much of a change. I have
only done the 2 front doors.. and now i can hear the rear doors..... I used 5 square feet. Total cost per door 35.00 including tax.


You can see that not 100% of the door is covered. Time per door about
an hour.. The rear doors will probably take 30 minutes.....

Next project.... rear doors... stay tuned

[tully]

Did the passenger rear door. Easier to to then then the front doors and less
material needed (about 25.00). Also added some more underlay to the door panel where toyota did not have any, especially around the edges. Initial findings?
I HAVE to do the other rear door. One can now hear a very noticeable low pitched hiss that was masked by all the other road noise.

Some Summary info:
what i have found is that the insulation/sheeting filters is effective
as follows on a scale of 1 to 5 (five being kills all sound, 1 did not help much )

high pitch hiss, whistle 5
medium hiss 4
medium low 3 (same frequency as the heating fan...)
low 2
very low 1.5
subwoofer rumble 1

Found some recyled rubber matts at a building supply for 5.00. They are meant
for gyms or for fatigue matts... May buy some and put them UNDER the carpet on the floor to dappen that low rumble on coarse pavement....

another good local link...
sound proofing Camry to Lexus conversion.

[AML]

Looks interesting and pretty reasonable cost. I was going to ask whether or not you were planning on tackling the floorboard next as well. I wonder...has anybody ever thought of adding anything to the roof?

Based on the reports of the effectiveness of Dynamat, how would you say your method compares?

[tully]

yes, i will be doing something about the floor next, the roof never... more noise comes through the glass then the roof....
Dynamat is a fine product. It is exactly the same product as what I am using only its
thicker. It may work better but i am not convinced. The theory on how these products work is that they convert noise into heat. Does that mean thicker is better? The other consideration is weight.. I added about 8 lbs of weight to the car.

[tully]

Added 3/8 rubber matting underneath the carpet. I only did the easy parts... left the 2 front seats installed and did not do the area underneath the front seats. It made enough
of a difference to make it worthwhile. Now I hear road-noise directly behind me. I am
pretty sure its either coming from the Hybrid Battery Vent or the read deck. Will get someone to drive the car while I poke around with a meter.

[assailantsky]

Keep up the good work tully. Really good information you are providing here. Do you use a service manual to strip the car? Could you post a copy here so I can follow in your foot steps?

[Frodo65]

Originally Posted by tully

Added 3/8 rubber matting underneath the carpet. I only did the easy parts... left the 2 front seats installed and did not do the area underneath the front seats. It made enough
of a difference to make it worthwhile. Now I hear road-noise directly behind me. I am
pretty sure its either coming from the Hybrid Battery Vent or the read deck. Will get someone to drive the car while I poke around with a meter.

If you ever have a water leak or a significant spill, a non-permeable rubber mat will be a rust magnet as it guarantees that the metal panel will stay moist for the duration. In high-humidity weather conditions, it may present condensation problems as well.