For some strange reason my excavator has carpet like material with some type of foam backing on interior of cab, except for firewall (behind seat). I am assuming they didn't put anything there as it does warm up after 3-4hrs of steady work. I see they put foil backed insulation in engine compartment up against firewall. During this semi-annual tune up, I ripped out my floorboards and rubberized all edges where they mate with each other and filled all cracks with rubber. Now, things have stopped rattling, but the tin can is still loud (improvement though). I figure if I can find something to stick on the wall behind seat, I will stop sound from bouncing around. What sort of material do you think would work? It has to take a little heat from time to time and cannot be toxic if heated or frayed. Is there something NAPA would sell for cars? thx.
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Northern_Kevin
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I don't have any affiliation but I have used Dynamat before for building cars, stuff worked great and was decently priced off of eBay and the like. http://www.dynamat.com/
Ha...you must have ESP...Today, I just bought a carton (25sqft) of Auto-Chem soundproofing (Canadian manufacture)...very much like Dynamat. Just stumbled into Napa looking for nothing, and asked the parts guy if he had any...turns out a customer ordered a box of the stuff but never showed up. So, I look forward to installing it. It has a aluminum covering on one side. I had narrowed it down to this: http://www.amazon.com/Stinger-RKCP12-RoadKill-Carpet-Pad/dp/B001TH8OC4/ref=pd_sim_sbs_e_15 and http://www.amazon.com/Rattle-Trap-FatMat-Install-Included/dp/B003TUNRGM/ref=pd_sim_e_5 With shipping costs and whatnot, I put it on the back burner (23 pds for Fatmat). Got a dubious sound meter for phone...will measure before and after to see if there is any difference. The little bit I did with rubber tape for floor plates and HVAC box made a difference. Amazing how a little rattle adds white noise to the cab. Still looking for a closer source than the UK for that egg carton look foam...
Northern_Kevin
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I've tried the sound meter with my phone before, it worked decently, at least you can measure on the same scale with using the app for a before and after. But it sounds like you got some good stuff for the job.
I haven't installed the sound dampening stuff yet, but I got measurements. I have two different sound meters programs on my phone. Sound Meter V2.1 by Trajkovski and Siund Meter v1.4.7 by smart tools. I though the latter one would be the best, as the interface seemed slick, with meter and graph, but it seemed to stall at higher readings. The first one has a 'classic' meter, but it seemed more sensitive. Anyways, at 1min runtime in idle, I got 98/97dB (door open/door closed) and 86/86dB (second program). After 5 min, full throttle, door closed, I got 93dB/86dB and standing outside door, 81/79dB. After 10min, at idle, closed door, I got 91dB/86dB. Note the second program stayed at 86dB throughout (door closed). The first program ramped down from 98-91dB from 1min to 10min. Will see how these numbers change once I get my padded room finished...lol. Looking for some thick padding/foam....
Got a little busy and installed the sound dampening stuff...still need to remove the ducting system for heater/ac, but I got the floor pan, cover over ac/heater unit, behind seat (high), metal strip on ceiling, glovebox (behind seat). Was going to remove the OEM foam/carpet on ceiling and cab supports, but they glued those suckers on, so I'll just leave them (1" med weight foam with carpet like cover). I also need to find some heavy foam/carpet for behind seat. I got a reading as low as 82db after warmup on first program, which is a 9db drop. The second program actually registered a 81db at startup, but then stuck on 86db for all other readings...something not right with that program. I flirted with high 70's while playing with throttle...trying to remove resonance. As far as seat of the pants impression, it made a noticeable difference. Of course, not as much as I was hoping, but if I get behind seat with foam and plug leaks where hyd lines go to left joystick, I might get into the 70's. The higher frequencies were muted more than the lower. Makes sense, given the stuff I put on is made for reducing higher freq.
What I should have done is record the noise before and after, then use a freq analyzer to chart freq of both times...would see which freq I lost, and which I didn't. The db meters measure sound pressure, but not freq...it is those high freqs which get to me. After warmup I played around a bit regrading my parking area without earmuffs...been a long time since I've done that. One thing that was very noticeable, is before I would notice a big improvement by leaving door open, but now, there is no difference (tin can feeling is gone).Finished soundproofing Bobby. Pulled apart the right console (fun trick to recovering ignition switch - fishing line), HVAC, and laid down the Al faced butyl stuff, then put in 3/4" rubber foam that I found used for making standing pads (checkouts etc.). Did the same to left hand column, and behind seat. I didn't get down to the 70's, as I was hoping...not a big change from what I reported above (few dB less). Suspect the rubber foam isn't dense enough to do much good....thankfully, it was only $8. Overall, the whole process made a big difference, as it doesn't feel like I am in a tin can anymore. The dB meters suck. One seems to like 86dB no matter what, and the other seemed to work better, but now I am not so sure. The thin heavy weight butyl based stuff made the biggest improvement. I can talk in cab and hear myself clearly. I suspect if I addressed the top of engine compartment, where the noise comes from, I'd make better gains. I've been looking at newer models, and they really cover the engine compartment well with heavy foam (no gaps like mine). Since the top of engine compartment has nothing, anything should make a difference...just have to find fire rated stuff. Seen pads use for under hoods of cars...will try that. Think I have a spare somewhere when I bought my new car...a customer decided to play with the original and creased it...