Mass loaded vinyl is one of the best for stopping low frequency sound (road roar). It is a very heavy and dense material. If you use it, you must overlap any joins otherwise all the effort installing will be wasted with noise coming through the gaps. It works well, but you must add a thin decoupling layer between the surface to be soundproofed and the MLV. Foam sheet is fine.

I have it in the boot and under the rear seats of my Subaru. It stopped enough noise for me to be satisfied, so I didn't go the whole hog and remove the front seats and carpet to cover the entire floorpan.

Tyres make a difference too. My Vredestein Quadracs were terrible for noise when they got older (the more aggressive tread pattern maybe contributing), the Goodyear Efficient Grips that replaced them are superb.

Edited by corax on 07/08/2018 at 14:10

Yes it does work.

If you have a small to medium FWD car the chances are that putting soundproofing over the rear wheelarches and over the boot floor and under the rear seating will reduce road noise considerably.

One you've got rid of the bulk of the noise, you'll hear where the rest of it is coming through and can deal with sections at a time, doors and rear quarter panels let the sound in too.

I've soundproofed several small family hatches now, as Corax notes the main passenger floor rarely needs anything doing, nor the front firewall/bulkead, though often sound can be coming in via the front wheelarches which like the rear ones on mainstream makes may well have no insulation whatsoever between the arches and the thin plastic trim covering them.

Its simplicity itself to trial and costs nothing, gather an armful of duvets and blankets and cover the rear arches, the boot floor and the rear seat area, then go for a drive see what you think, you'll know instantly if it's worth pursuing further.

No need for gluing felt any more, have a look at ebay item 263257476842, this is the type of product i used (but bought elsewhere), remove the trim where necessary, look in disappointment at there being nothing other than painted steel bodyshell, cut to shape stick the stuff and put the trim back, job done.

Edited by gordonbennet on 07/08/2018 at 16:12

Bit of holy thread ressurection batman stuff here - new post on 07-08-2018 has a product to promote.

Some interesting replies though, particularly that from GB.

Edited by Bromptonaut on 07/08/2018 at 18:29

Really, really not spam.

and on your Focus

Is this comment aimed at the OP?. If so, seeing as it was Apr 2008, i think that boat has well and truly sailed.