Cheap sound insulation

[Burdekin]

I've been doing quite a bit of research into what is the best sound insulation for my Amazon. Of course there is expensive stuff like dynamat but I reckon I can get as good if not better results and a lot cheaper. Big claim I know and maybe wishful thinking but I'll explain what I've learnt and a big thanks to Darren and the noise vibration guys at Tata. The first thing you want to do is add mass to large panels to stop them resonating, Volvo already did this on the floor but for improved results add it to all large flat areas like the doors etc and as a general rule you only need to cover 25% of the surface, the goal is not to block the noise with this, it's only there to add mass so the panel resonates at a much lower frequency. The sound deadening pads here http://www.automobiletrim.com/sound-proofing.htmlt cost £65 for 10 but if you already have the original sound deadening on the floor you won't need that much maybe only half but it's easy to work out, just measure and divide by 4 and that's all you need.

The next layer is an absorbent layer, absorbing sound in your car really isn't effective as you can't get the thickness required but this layer is very important to isolate the top layer. There are two materials I have found that will work well here depending on where you are putting it. There is the sound proofing felt here http://www.automobiletrim.com/sound-proofing.html that will work well on the floor and will be easy to lay and then there is Closed Cell Foam that will also work really well as the middle layer and would probably be better for areas like the doors but will work fine on the floor as well but will probably be a bit harder to lay. The foam doesn't need to be too thick as it's main purpose is to isolate the final layer, I would say 3 to 6mm will be plenty. I have found this cheap option and I think would be ideal: http://www.needlesports.com/Catalogu...ength-BEA-TULM

The final layer is the sound blocking layer and the best material I have found is Mass Loaded Vinyl but the original rubber matting probably will work okay as well here. When using closed cell foam as the middle layer I would bond it to the Mass Vinyl Layer. You also want to cover as much area as possible with the middle and top layers and you don't want gaps where you join the final barrier so overlap the seams and glue them together. I haven't found many places selling Mass Loaded Vinyl but I have found this website selling it at a very reasonable price http://www.domesticsoundproofing.co....barriermat.htm

So that's it. There's also things like blocking all holes in the bulkhead and the wheel arch protectors would probably help reduce road noise transmitted from the wheels.