I can't hear myself thinking while I drive. Help!

January 5, 2010 8:59 PM

How can I quiet the interior of my car on the cheap?

Long story short, I bought a Honda Civic awhile back and the level of interior noise has been bugging me for some time now. It is to the point where I have to turn up the volume on my stereo to louder than I'd like while driving down the highway just to listen to talk radio.

I'm a student so I don't have a ton of cash to spare. I've heard good things about Dynamat, but I really don't have the resources for that. I also came across this, but I don't know about the quality.

Oh, as a side question, there's also a small hole in the firewall that has been letting in cold air. I'm not entirely sure how I should go about patching that up. I would imagine that getting that repaired might also reduce some of the noise.

So, auto-savvy MeFites, what's the best *cheap* way to insulate my vehicle's interior from outside noise?

posted by sciencemandan to travel & transportation (9 answers total)

I used the foil backed insulation to which you linked in my GEO Metro with good results. Only drawback is you have to completely remove the entire interior of your car & snugly cover every possible surface in order for it to be effective. And yes, patch that hole.
posted by torquemaniac at 10:12 PM on January 5, 2010

Patching the hole is your main priority; depending on the size, a rubber grommet or heat-tolerant rubber sealant might be all you need.

Beyond that, what kind of noise is bothering you? If it's engine noise, underhood soundproofing might help. If it's tire noise, do some research at The Tire Rack or similar to see if that tire is known for being noisy¹ and consider replacing them if so. If it's road noise, it's going to take a lot of soundproofing and thus a lot of expense, which is why the manufacturer left it out in the first place. If it's wind noise, there's not much you can do.

¹I switched the wheels and tired on my 1993 protege from the ancient OEMs to performance Kumhos that I had laying around, and the amount of noise coming off those tires was staggering; I switched 'em back before I sold it, and it was such a quiet car again, I considered not selling it.
posted by davejay at 10:29 PM on January 5, 2010

Peel & seal is a roof-repair compound that's designed for home/mobile home repair, but it can be used as a cheap Dynamat substitute. Put it on the floor under your carpet, and maybe on the insides of the doors if you're feeling ambitious.
If the hole in the firewall isn't too big, (say, under 1" in diameter) you can use aluminum tape to repair it.
Also - how's the muffler? Since it's a Honda, a previous owner may have put a "performance" muffler on it that does little to improve performance but makes the car sound like a hive full of angry bees. Does the tailpipe look big enough to launch a grapefruit? You might want to think about a new muffler rather than sound insulation.
posted by zombiedance at 10:30 PM on January 5, 2010

DIY sound proofing paint: One gallon latex paint, one quart fine clean quartz sand, one quart ground up rubber (ask at a recap tire shop) you can substitute ground up latex foam rubber. Mix well (maybe get a blender at a thriftshop) and apply with a paint roller, you need a solid coating but not a too thick a layer, it works by converting sound to heat, the quartz absorbs high frequencies and rubber absorbs lower sound vibrations. Take off the door panels carpets and headliner and give every thing a coat. Let dry and reinstall interior.
posted by hortense at 10:54 PM on January 5, 2010

Yeah, you really do need to first determine what is causing the noise. There are countless sources: tires, wheel bearings, engine, wind (e.g. window not rolled up all the way or rotted weather stripping), exhaust, loose interior trim (rattling). Once you've determined which one of these is the major source of noise you can do something about it. I would definitely look into the tires as davejay said because there is tremendous variation there -- tire design is all about trading off one something in one category (noise, lifetime, grip, wet performance) for another.
posted by Rhomboid at 10:57 PM on January 5, 2010

Ear plugs will be the absolute cheapest, most effective way to cut down on the noise.
posted by 6550 at 11:50 PM on January 5, 2010

Earplugs are a horrible idea. Wearing them means that you can't hear other people honking to warn you of danger, or hear sirens from approaching emergency vehicles. Don't ever wear earplugs (or earphones) while driving a car.
posted by chrisamiller at 11:59 PM on January 5, 2010

If you find that you're getting wind and road noise from the windows (and you probably are) spray a light coat of silicone lubricant onto your window channels. The windows will more securely close, cutting down on wind noise.

Also, check your exhaust (mufflers and forward) for holes. You can get a lot of noise from there.
posted by zippy at 2:42 AM on January 6, 2010

Most of the noise is generated by wind and tires. Visit Tire Rack.com or Discount tire direct.com and search for tires that match your model Civic and pick the ones that get the best noise rating.

As far as patching that hole in the firewall, get some of that metal tape and slap a few pieces of that over the hole.
posted by Jon-o at 4:19 AM on January 6, 2010