# The Definitive Cheap Dynamat.



## Pensive666 (Jun 18, 2011)

OK there are millions of hits of people using bitumen tape in their car for sound damping. It works - but you have to put at least 2 layers on because its so light and flimsy. I bought some to have a look - I shall be taking it back because of the horrible smell it emanates. Luckily I hadnt applied any before I noticed the tarry aroma.

So I resolved to buy some proper stuff today - I've used Dynamat before on my previous car and it was excellent. Decided to get some......

Halfords were selling overpriced vibe crap (its probably very good, but not for that price!!!), so thought I'd try the ICE shop - but Techne in Basingstoke appear to have closed so I popped into B+Q on the off chance they had something esle on the shelf.

And I found this!!!! its Butyl Flashing Tape for conservatories! (as you well know I hope, bitumen = oil based = plastic melting - hence the need for the butyl alternative.)

I've done the maths. Its basically 95% identical to dynamat extreme (with slightly thinner foil), same thickness, but half the price. Or a quarter if anyone is feeling bold and wants to order a load from shandhigson!!! Check it out in the table - its half the price AGAIN of what I bought in B+Q, but I can't guarantee the weighting of it I'm afraid.

Pictures tell more - and I even did you all a table here:









And some more pics - this is the particular tape and its weight.

















And this is what it looks like in my boot. That is one full reel - 2.5Kg worth @ £25.82. And it does just as good a job as Dynamat. Still need ot do the sidewalls and move into the cabin with it but I'm happy with what ~I've put in so far. I used the "tap test" to work out where to stick it all (in areas where I wasn't providing total coverage.)


















I estimate I'll need to put in around 3 to 4 rolls worth to cover the sides, beneath the rear seats, rear sides, and driver / passenger door - which is £100 the lot. Bargain in anyones book.

Also I weighed the spare - its 16Kg with tooling - if I remove that I should cancel out all but around 2 kg of my subwoofer and sound damping install.

DO NOT USE BITUMEN FLASHING TAPE. IT bl$£%y stinks and its messy - this stuff is exactly the same as dynamat and I did the entire boot in about an hour.

Easy now Rude Boyz and Girls...


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## Pensive666 (Jun 18, 2011)

Addendum: weighed my sub and amp, 16kg. So a full install will be about 26kg, including damping. It's only really a third of the weight of a passenger so not the end of the world.


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## kazinak (Mar 23, 2010)

Flashing tape are shit comparing to dynamat, you will need at least tree layers to get similar result as dynamat, and it will cost more in the end anyway


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## Pensive666 (Jun 18, 2011)

kazinak said:


> Flashing tape are shit comparing to dynamat, you will need at least tree layers to get similar result as dynamat, and it will cost more in the end anyway


Did you read the post? With respect to bitumen flashing, you'd be right.

But in this case, that isnt true. It is simple physics. All of these things are simple physics.

http://www.sounddeadenershowdown.com

Resonance damping is entirely dependant on the weight of the resonant panel.

Dynamat Extreme = Butyl and aluminium.
Corotherm Butyl Flashing = Butyl and Aluminium.

Look at the weight per cm2 (in grams) column in the spreadhseet. The Butyl flashing I used is exactly the same weight per cm2 as Dynamat Extreme (30g / cm2). I did however incorrectly label the column as m2 by accident).

Ergo - One coat of Dynamat Extreme will perform exactly the same as one coat of this flashing, only its twice the price for dynamat.

They are made of EXACTLY the same materials. They do not have Magic Dynamat Butyl which performs twice as well per gram as Flashing Butyl. It's Butyl. Its weight, attached to a resonant panel. How much it weighs DIRECTLY corrolates to its resonance damping performance.

What you are talking about there, sir, is Marketing Magic. There is no such thing as magic!

________________

Incidentally > I've been looking into it.

To summarise SDS website - for most cost effective and minimal weight sound damping:

1) Cover 25% of the metal panels with Dynamat (or my chosen alternative) - (Resonance damping)
2) Cover EVERYTHING with a Mass Loaded Barrier which is just a less dense, higher volume material than dynamat like Vinyl. (kills 15hz to 4000hz)
3) Cover all of the vinyl with a thin layer of closed cell foam. - (High Frequency filtering).

For number 2) You want around twice the volume, at half the weight, so Mass Loaded barrier would be 4 times less dense than dynamat by volume. It doesn't matter what the product is really as long as it is within those limits.

Compared to two coats of dynamat on everything, it would weigh less than half as much!

Double Dynamat :
2 coats of Dynamat on everything would be at least 25 Reels (approx EG: 57.5 Kg)

SDS Design
The SDS arrangment would probably weight around 21 KG, if that (Dynamat @ 25% single coat, 7.2Kg CCF @ 7 Kg, MLB @ 7.2Kg)

The problem is that Because Dynamat is so dense, you end up putting LOADS on to try and damp down frequencies which are better damped by a less dense material. Thats not what its designed for.


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## kazinak (Mar 23, 2010)

i've used flashing tape in the past,and it was alright, until i've tried dynamat xtreme,
sometimes expensive = better qaulity :wink: 
some as with the head unit, good ones cost £300-400 ,rubish - £50-100 ,


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## Spandex (Feb 20, 2009)

kazinak said:


> i've used flashing tape in the past,and it was alright, until i've tried dynamat xtreme,
> sometimes expensive = better qaulity :wink:
> some as with the head unit, good ones cost £300-400 ,rubish - £50-100 ,


In that case, I heard on the grape vine that Pensive666 is selling this new sound deadening stuff called Supermat Xtreme to the Power of MaXXXX"... It's twice the price of Dynamat Xtreme, so you can only imagine the quality.

PM him for details.


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## Pensive666 (Jun 18, 2011)

Spandex said:


> Pensive666 is selling this new sound deadening stuff called Supermat Xtreme to the Power of MaXXXX"... It's twice the price of Dynamat Xtreme, so you can only imagine the quality.


Haha lol don't tempt me! I put dynamat on my last car - The only difference between them (that i can see) is the thickness of the ally. Dynamat is a bit thicker, which would make it slightly better. The perfect thickness would be the same thickness as the panel you are damping.

But seriously, in the face of the facts, would you really pay DOUBLE on the off chance theres truth in the rumour, or go for something which will clearly do a near-as-dammit-identical job?

It's not for everyone, but it's most definitely for me!!!!


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## Pensive666 (Jun 18, 2011)

Update: Added a bit more damping under the seat during the install as per below:









Will probably add some more next weekend though - at 2.5Kg per roll its worth it. I'm also looking at possibly deleting the tow ring, and I understand there is some handling ballast somewhere which could also go - assuming its sprung weight at the back, should be perfectly safe. There's also the spare, but i'd rather lose the useless bits first, if possible.

Following Wak's OEM Radio install guide to get RCA's out of the stock HU (with the exception of resorting to careful use of pliers to extract the crimped RCA leads from the autoleads adapter. Paperclips, safety pins, staples - none of that worked at all! I trashed one rca lead before giving up and resorting to the Jaws of Death.)

Got my sub installed - everything worked first time - and here we have a little piccy for you my lovelies. Guess the thread should be renamed now.

And yes - it's all mutant.

And no - it doesnt sound noticeably worse than all the fosgate stuff some filthy tealeaf whipped from my old car.

The dynamat has a much greater effect on the sound than an expensive sub! True Dat. :mrgreen:

As for the positioning - I decided to put it smack inthe middle to preserve balance - despite driving the car on my own most of the time to work - I don't want to try and get clever diagonally balancing the sub against the driver - it will probably not have the effect I expect =D










Next stop - Door panels gonna get the butyl treatment. Waiting for now - might want to upgrade the BOSE speakers while I am in there - not really sure.


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## jamman (May 6, 2002)

I so want to go buy a skateboard now but I'd break it


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## Pensive666 (Jun 18, 2011)

jamman said:


> I so want to go buy a skateboard now but I'd break it


+5bhp if it's Canadian Maple!


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## robokn (Feb 21, 2006)

So you have filled your car with sound deadening and then you put that sub in, not exactly the best around for the effort you 
have done :? :roll:


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## Pensive666 (Jun 18, 2011)

Already had it all in the garage, so it was free! I have a plan to replace the spare with a fosgate slimline, so it's a temporary fix for now. Alternatively I could upgrade sub & amp at any time in about 20 minutes, so it's not like I'm stuck with anything!


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## Pensive666 (Jun 18, 2011)

SO - I've done the doors 

A couple of pointers:
1) I got confused by Waks instructions - leave the rearward rubber seal attached to the door CARD, not the door panel.

2) one roll of this stuff is plenty - I did a single coat, then a tap test and doubled up in the areas where there was still a boingy noise. I had enough left over to triple up in the centre.

3) Don't worry if there are bits you can't reach - just add "another coat" to the accesible central area and the resonance damping will still work just the same. This stuff is not to block audio frequencies, but to prevent the amplification of them by the door skin.

It works AWESOME! the door sounds like my old beemer now. happy Jon.


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## New2AudiTT (May 7, 2011)

Pensive666 said:


> OK there are millions of hits of people using bitumen tape in their car for sound damping. It works - but you have to put at least 2 layers on because its so light and flimsy. I bought some to have a look - I shall be taking it back because of the horrible smell it emanates. Luckily I hadnt applied any before I noticed the tarry aroma.
> 
> So I resolved to buy some proper stuff today - I've used Dynamat before on my previous car and it was excellent. Decided to get some......
> 
> ...


This is a great post mate. Really helpful. Just wondering if you've done the Bonet as well with Butyl Flashing Tape considering the heat?

Am thinking of getting these: http://www.cbsonline.co.uk/product/Soundmat_Pads_SOUND

any advice? good/bad


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## RudeBadger (May 15, 2010)

I just brought a pair of these.... pop them on when you get in the car, no noise.... job done !


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## kazinak (Mar 23, 2010)

New2AudiTT said:


> This is a great post mate. Really helpful. Just wondering if you've done the Bonet as well with Butyl Flashing Tape considering the heat?
> 
> Am thinking of getting these: http://www.cbsonline.co.uk/product/Soundmat_Pads_SOUND
> 
> any advice? good/bad


why you want to do the bonnet :lol: :lol: :lol:


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## New2AudiTT (May 7, 2011)

why you want to do the bonnet :lol: :lol: :lol:

Have a look at this http://www.noisekillergb.com/product_de ... ?ItemID=75

Apparently to reduce engine noise. Dynamat also mentions this.

Any advice much appreciated


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## Pensive666 (Jun 18, 2011)

New2AudiTT said:


> This is a great post mate. Really helpful. Just wondering if you've done the Bonet as well with Butyl Flashing Tape considering the heat?
> 
> Am thinking of getting these: http://www.cbsonline.co.uk/product/Soundmat_Pads_SOUND
> 
> any advice? good/bad


Nope - I haven't done the bonnet - You'll need special stuff to survivie the heat there.

Once I'd done the Wakbox I realised I'd totally undone all the work I'd done with the sound damping =D

But the subwoofer sounds better, which was my primary goal.

Those soundmats will do fine, but you get a slight benefit with dynamat in that its easy to cover an entire panel. This has a very slight noise damping effect for certain frequencies, but resonance damping performance will be pretty much the same.


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## Garth (Feb 7, 2012)

Pensive666 said:


> Nope - I haven't done the bonnet - You'll need special stuff to survivie the heat there.


Not true actually. Dynamat or equivalent is more than up to the job. I have done this on my last 5 cars and never had any problems. Here's my mk5 GTI done:









I would also recommend checking out ebay for sound deadening. I got my last roll from there and it was way cheaper than the B&Q Butyl Flashing mentioned on this thread. I bought a huge roll identical to Dynamat extreme for £50 which was enough to do almost 2 FULL cars. I forget how much I got as it was over a year ago, but it was in excess of 20kg. As always, it pays to shop around. There are no rewards for customer loyalty in these days of recession! :wink:


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## New2AudiTT (May 7, 2011)

Garth said:


> I would also recommend checking out ebay for sound deadening. I got my last roll from there and it was way cheaper than the B&Q Butyl Flashing mentioned on this thread. I bought a huge roll identical to Dynamat extreme for £50 which was enough to do almost 2 FULL cars. I forget how much I got as it was over a year ago, but it was in excess of 20kg.


Thanks Garth. Do you know what it's called mate? or which one would you recommend from e-bay. Would like to get Dynamat equivalent. Otherwise, will get Dynamat Extreme from Amazon but a bit expensive at £139 [smiley=bigcry.gif]

Cheers


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## dubberdean (Dec 22, 2011)

Pensive666 said:


> kazinak said:
> 
> 
> > Flashing tape are shit comparing to dynamat, you will need at least tree layers to get similar result as dynamat, and it will cost more in the end anyway
> ...


You are correct it is simple physics, but just adding mass to a panel does not insulate in the same way as a material that added both mass and had other noise insulating properties.

I've been advocating the use of flashing tape particularly in VW campervans for the past 5 years, but you do have to be completely open with the science behind the suggestions so that people can make their opinion on what is the best value for them.


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## Gone (May 5, 2009)

I used some ebay stuff called edead. It was essentially butyl flashing backed onto ally foil. I was a bit circumspect doing it on the cheap but as the man says when you look at the materials of construction , density and price it's hard to see what dynamat offers that builder's materials don't.

The only thing better might be that Spectrum sludge that wizbit or whatever he was called used in his sound deadening build thread, but I'm not sure if I could be arsed with all that effort.


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## Garth (Feb 7, 2012)

New2AudiTT said:


> Garth said:
> 
> 
> > I would also recommend checking out ebay for sound deadening. I got my last roll from there and it was way cheaper than the B&Q Butyl Flashing mentioned on this thread. I bought a huge roll identical to Dynamat extreme for £50 which was enough to do almost 2 FULL cars. I forget how much I got as it was over a year ago, but it was in excess of 20kg.
> ...


just do a search for sound deadening and you'll find loads. something like item number 180766114387 would be fine. Take another look though as there may be cheaper (mine was). I didn't do more than a 30 sec search just now.


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## Pensive666 (Jun 18, 2011)

dubberdean said:


> Pensive666 said:
> 
> 
> > kazinak said:
> ...


Yeah, it's just from experience - I've installed stereos in all my cars from Peugeot, Alfa, seat, vauxhall, up to BMW 7er and a Saab 9000.

By far the best insulated were the BMW and Saab, both sounded incredible, the Saab best of all. I couldn't add any dynamat - they had already soundproofed the entire car beyond my wildest intentions.

Having added dynamat to lesser cars, it doesn't do much to stop noise. None of them managed to get halfway close to the Saab.

If you want quiet, Dynamat alone is NOT the way. I prefer not to imply that 2 coats of dynamat is going to silence your car because it wont.

Saab used what I can only describe as the densest expanding foam over "dynamat" style weight sheets.

It was just dead.


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## Garth (Feb 7, 2012)

Pensive666 said:


> Having added dynamat to lesser cars, it doesn't do much to stop noise. None of them managed to get halfway close to the Saab.
> 
> If you want quiet, Dynamat alone is NOT the way. I prefer not to imply that 2 coats of dynamat is going to silence your car because it wont.


Depends on the reason for sound proofing, i.e. the kind of sound that you are trying to eliminate. Dynamat (or equivalent) is great at stopping resonance and vibration noises, which is the reason I have used it. It's great for getting rid of exhaust drone or rattles from speaker bass and not bad for general road noise. BUT it's only half the story... if you use dynamat as well as sound proofing foam, it really does make a big difference.


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