I've learned from reading posts that the most effective per ££ material for noise suppression is S - C.
Primarily I want to suppress road noise....it sounds like most come from the rear tyres.....?????
So can someone tell me where to prioritise, - doing what areas gives the best reduction. I've seen mention of doing the doors....should that be done or only of benefit to audiophiles (I'm not one).
And what size(s) of sheet are best?
One question
What size and make of tyres are you running?
And an aside, aren`t those Scottish roads a bit rough unlike our magnificent Welsh roads s:lol: :lol: s:lol:
(http://www.focusst.org/forum/attachments/focus-st-electronics/120778d1453101266-nvh-removal-cabin-using-dynamat-filtreavibration-uk.jpg)
There is a little science behind it. You want to target stuff in front and behind each tyre. Wheelarch liners often have stuff on the back of them too.
I am sure there was someone else recently who did a similar exercise.
Standard FL sizes, Toyo Proxes.
Rough roads..... I'm sure they are..... s:evil: :evil: s:evil:
I recently did my car and popped a couple of pictures up I think
(http://i991.photobucket.com/albums/af36/skt_photos/20170329_145223.jpg) (http://s991.photobucket.com/user/skt_photos/media/20170329_145223.jpg.html)
(http://i991.photobucket.com/albums/af36/skt_photos/20170329_145201.jpg) (http://s991.photobucket.com/user/skt_photos/media/20170329_145201.jpg.html)
I also put about 3 stick on carpet tiles inside the doors on the rear bins.
I worked on the principle of putting a bit of silent coat in the centre of the panels that made most noise when you tap them. I didnt try to cover everything as you get most of the benefit by using a small piece and only slightly better result by using a large piece. I could probably have used less than I did. My sheets were something like 187 x 265 mm and I didnt use anything like a complete sheet anywhere.
I put a lot of it on the rear firewall to reduce the noise of the engine but less in other parts of the floor. I am very pleased with the result and am now bothered by the wind noise of my hood at speed rather than engine noise!
I guess it's important to be specific on what noise you're trying to kill
If its a vibrating panel or trim piece (the vibration being caused by tyre noise or engine noise, or the movement of a speaker) then Silent Coat type deadening will help.
But if its the actual noise from the tyres (or engine) it won't help much against those specific noises, you need an acoustic barrier. The most popular for automotive use is MLV (Mass Loaded Vinyl)
As hinted at above, a complete shell of this around the backs of the plastic wheel well shrouds will block tyre noise (as would a complete covering of the bulkhead against engine noise) BUT noise seems to be able to seek out the next shortest route to your ears! So you may spend a fair amount of time and money sealing the noise into the wheel well only for it to leak out the side and in through door gaps, Windows or (most likely) our floppy roofs!
If you use the MLV, it will need isolating from anything it can touch. It only blocks airborne sounds, not physical vibrations. So it needs at least one layer of CCF (Closed Cell Foam) between it and the panel its attached to, maybe another on the other side if sandwiched between trim panels or something
There is a site called "sound deadener showdown" with a bit more science and explanation, worth a read. There's a section on convertibles.
Also, while its true you see the most benefit from Silent Coat or similar with only 25% area covered, it should be in one piece as large as possible. If you had four pieces say 1"x1", they do not have the same effect as one piece that measures 2"x2".
Similar with MLV, it has to be one giant layer to work, or at least overlapped by quite a bit, as the sound just looks for an easy route through gaps or around edges.
Phew!
Thanks for the info folks, anyone else like to relate what they've done?
only have some door sound deadening , cant hear the the tyres unless going 70+ or pushing in the corners.
exhaust and roof are slightly louder than stock though.
swap your good roof for my crumbling one and it'll be fixed , probably s:P :P s:P
Found this really helpful, as purchased Silent Coat for the doors as a starter to see how much of a difference it will make, just need to the time to sort it - as with all the other jobs that need doing!
Excellent comments! Will be doing the same to the doors as well this summer - silent coat + closed cell foam. Has anyone put anything on the rear firewall/bulkhead? If yes, then which part exactly and how did you get to it?