Sound proofing thread

alexthecheese

alexthecheese

alexthecheese

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I've always had a bit of an obsession with noise levels in cars and sound proofing them. I had a special bus converted to a camper and spent weeks sound proofing that, same with cars.

Anybody else have experience in this area? I've always used dynamat extreme, but it's ridiculously expensive and I don't have any money these days.

As you can see from my other thread we've just purchased a Honda Civic. Unfortunately due it's low gearing, 70mph in 5th is 3500rpm. Not ideal motorway cruising ratios. When it comes back from having a new clutch fitted I'll be pulling out the interior and sound proofing it.

What alternatives are there to pricey products such as dynamat? I've read about flashing tape and closed cell foam. Flashing tape to simulate the dynamat, stopping panels from resonating, and the closed cell foam to absorb and block the sound. The flashing tape is about the order of ten times cheaper than dynamat, and closed cell foam can be bought in a range of sizes and thickness to suit your need.

All of that seems to markedly improve the acoustics of your car, which is why it's popular in the ice world, but I'm after Bentley levels of sound deadening on the cheap. :p

Let me know if anyone else has experience in this.
 
i have used flashing tape on the bare metal inside doors and to line the door cars too of various cars

if you give the panel a knock with your knuckle you may or may not hear a resonance. the flsahing tape adds enough damping to reduce that resonance, it just makes everything a bit quieter
 
buy the paint on stuff, you can get into all the nooks and cracks, and layer it up as thick as you need
 
Surely you'd need to start off with a car that is already reasonably quiet? It'll cost a fortune otherwise...
 
I did most of my first car (Corolla) with flashing tape. It did make a difference but it also added a lot of weight.

The benefit of Dynamat Extreme over flashing tape is how light it is.

If you want Bentley levels of sound deadening don't buy a Civic. :p
 
Try using silent coat, I'm told it's just as good as dynamat but a lot cheaper. I used some silent coat extra on my doors and it's made quite a big difference.
 
Silent coat here too.
I did both doors, the floor and the boot of my S2000. Mainly for acoustic reasons but it did make a huge difference to the road noise.
Also, my doors make a satisfying thud when closed.
 
I Dynamatted my last daily which was a 2000 Yaris, did make a big difference - also wedging packing foam in some of the gaps helped stop a lot of the cheap plastic rattling quite so bad. Before I did it I was worried it would affect my economy however I didn't really find it made any difference - far less than just driving with a lighter foot!

Will see if I can find some pics later!
 
I suggest buying one pack of dynamat and doing the worst panels with that, then use cheaper stuff on the other areas.

Having used dynamat myself in the past I know it does make quite a difference,

I would dynamat the doors outer skin and the roof (if enough left over the boot lid to)

Then something like flashing tape everywhere else should help door inner skins etc. Maybe even apply an extra layer over the top of what has already been dynamatted for extra sound proofing :)
 
I don't have time for your first world problems. Lol, only joking. I wanted to soundproof my Rover 25 but decided I'd probably spend more than the car is worth on materials for it.

I saw some roofing sheets that were a bit cheaper than dynamat, there is also some cheaper stuff on ebay. I also have a bit of a fetish for soundproofing things. I'll wait until I have a quieter car first though.
 
Dynamat tbh seems like a scam. Butyl backed aluminium that appears to be identical to flashing tape but supposedly offers markedly better sound insulation sounds like a load of codswallop. I'll be going down the cheap alternative route, but if that silent coat is cheap enough I might give that a go.

I don't think you need to start with anything premium, though you'd obviously never bother sound proofing a Rolls Royce.
 
The cheapest way of doing this is to go to Wickes and get an 8m roll of the bitumen roofing material (it used to be £25, so probably nearer £40 now). I don't mean the gravel coated stuff btw!

It's about 3mm thick, fairly soft and technically much the same* thing as some deadening materials, just way cheaper.
IIRC it is self adhesive, but you can get a cold bitumen compound for gluing additional layers if you need to.

There is a carpet felt material which should perform like a poor acoustic foam, but with the advantage of being really cheap.


*not the same as viscoelastic materials like dynamat,
they have a special compliant layer
 
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This thread has just reminded Me. A friend bought a mk4 golf recently. He came round and we had a chat in the car and I noticed his seemed echoy. We both sat in mine and noticed the same difference but couldn't figure out way. Could only be due to the sound deadening in mine
 
EliotG said:
Surely you'd need to start off with a car that is already reasonably quiet? It'll cost a fortune otherwise...
Click to expand...

Incorrect.

I have a Peugeot 206 that I spent £80 fully deadening.

The difference is incredible. "Thuds" like a more expensive car and on the motorway, it's actually very quiet.

Arches, quarter panels and floor pan were best done followed by doors and boot lid. Didn't bother with the roof.
 
I have used flashing, closed cell neoprene and off the shelf 'audiophile' stuff in the past.
Flashing was OK, but was a bit fiddly to install in some areas. The closed cell self adhesive neoprene was a joy to use being very easy to shape around the the lumps and bumps.
 
Finally dug the pics out!

Interior had to come out!

sound1.jpg


Just carpets and some trim left, the front carpets I didn't bother taking out - just lifted as required to save effort!

sound2.jpg


Sticky stuff that! Also ran any cables I needed while I was there!

sound4.jpg



Shame someone drove into the side of it bout 12 months later really :(
 
Used to use Marley Sealant Tape from B&Q (flashing tape). It only achieves mass loading resonance reduction rather than having any acoustic properties as such. To be honest it's always a pig of a job and it obviously won't make your car sound like a Bentley, whether you use Dynamat or not, since road noise doesn't just come through the doors and floor. People forget that most rattles aren't actually touched by applying tape to the door cards etc.

For example the bulkhead is a prime source of noise, and good luck Dynamatting that. Then all the cheap plastics will still rattle unless you go on a rubber washer / screw tightening session.

On a hot summer's day, the flashing tape stuff becomes very liquid and sticky and can fall off and jam up your electric windows if you don't get it on extremely robustly.

It might have made a slight difference to my old Fiesta, but I wouldn't say it was worth the effort personally.
 
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