Looking at installing Sound deadener under my carpet and behind rear seat.
anyone used some of the cheap matting or is Dynamat the way to go?

Dynamat or other adhesive sheets are easy to install and work pretty good, especially inside the doors.
They are a pain to remove later and on a mini I would be worried about rust secretly breeding underneath.
I would look at the underfelt type mats and just sit it under the carpet, and maybe tape it to rear seat panel.

I am curious as to why you consider rust breeding under dynamat to be more of an issue with a mini than with any other car?

I have used the Jaycar version of Dynamat. It was fairly effective in deadening the sound. By no means does it sound proof the car as some people claim. It simply dulls the noise.

I only used it in the front footwells. I really should do up the wheel arches and in the back.

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Ryan Filippi
Minis In The Gong
[email protected]
www.minisinthegong.com.au

I have (so far) installed Dynamat inside the front doors (sliding window) of my van and it definitely reduced a lot of the noise.
I have installed underfelt in my sedan everywhere and am now considering ripping it out and replacing it with the Dynamat as it works so well.
The only problem with it is the cost as it's certainly not cheap.

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Your imagination is only limited by the size of your wallet
"61 850 original and crusty (Mavis)
"64 Smooth Roof Van (Colin)
"67 Deluxe resto project (Monty)

Yep used dynamat on my fire wall seemed to help. My install tip is keep the dynamat sheets in the freezer whilst progressing with the install, it give you the chance to cut,stick, remove and modify, when it gets to ambient tempature it sticks like you know what to a blanket

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SPO41 Mk2 Cooper S very original
1993 R32 Nissan Skyline GTR

Anybody tried some products from hardware stores. bunnings they have a Aluminium foil coated with bituminous adhesive weatherproof flashing tape. I have heard this gives same results but cheaper than Dynamat.
would be interest if it works.

I used a cheap Dynamat knock off from eBay on my car. Did the roof, firewall, doors, floor, behind the rear seats, most of the car to be honest except the bonnet and boot. Don't think that Dynamat will sound proof your car, that's not what it is for. It increases the density of the panels to prevent them from vibrating (reverberating?? Is that a word?). Basically if you shut a door without Dynamat, it sounds tinny, if you shut it with Dynamat, it sounds solid.

Also, you don't need to cover the entire panel in the matting. For example, on the roof, I only have a cross of matting, so a strip down the middle of the roof front to back, and a strip through the middle left to right. This is all you need to do to each panel, any more will not give you any more benefit, it will just cost more and weigh more. That's the other thing, this stuff is HEAVY. I think mine was a total of 50-80Kg, maybe more, maybe less, I can't remember now, but I remember going to pick up the box and nearly doing myself a mischief.

Cheers,
Keels.

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-Wasabi
1972 Clubman - Daily Driver
1962 850 - EW1 Powered

Installed correctly dynamite has very good sound attenuation properties. The problem with sound proofing is you need to cover the surface absolutely, positively, completely edge to edge or else it is not very effective. Easy on a flat shape like a speaker enclosure, hard on a pressed metal panel. The felt material works well cas it is easier to conform to shaped surfaces.

Earplugs are cheaper and weigh a lot less.

Reverberation is a word and you used it correctly

I used the usual automotive felt underlay. The biggest improvement was the piece that goes in the engine bay behind the carbs.

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"Beware the lollipop of mediocrity: lick it once and you'll suck forever" Brian Wilson