Sound Reduction Puzzle

In the process of perusing the seemingly endless Land Rover restoration sites we could see that (so-called) “soundproofing” was a common step in most projects.   The term is a bit optimistic, one can never eliminate sound in a vehicle, so “sound reduction” is a more appropriate term.

All vehicles have some degree of soundproofing, it is the stuff under the carpet on your floor and the trunk/boot.  The thick piece of silver lined foam under the hood/bonnet is also soundproofing.  Depending on the vehicle and/or the preferences of the owner there can be any number of products and combinations thereof used throughout, including in the doors and roof.  People who are restoring older vehicles, whether they are 50s roadsters, 60s muscle cars, or 90s Defenders, will at some point likely decide to reduce noise by installing additional soundproofing materials.   Land Rovers are no exception as the various threads in Land Rover Forums show.

Defenders and other Land Rovers of their era were built as big utility vehicles and because of this and the large areas of the aluminum body they are probably among the noisier vehicles on the road.  Ours is absolutely utilitarian, and has only bare metal on the floors and walls.  The doors do have small patches of  sound dampening materials on the inside of the door panels, this would have been part of the factory production process.  The roof has quite a good piece of hard plastic liner behind the interior roof fabric, but that is not going to do much against the vast areas of bare aluminum.

We decided it was worth looking at sound reduction, but had no idea of where to start.   I started scanning for what materials worked best and learned a lot about  the science of sound reduction.  Obviously there is a huge sound reduction industry, but I was surprised to learn how much of it is devoted to vehicles.  I learn that there are two separate steps involved in sound reduction: the first is referred to as “dampening” or “deadening”.  This addresses noise generated or amplified by the body panels themselves and involves the installation of some sort of very heavy rubber/butyl material, lead is sometimes used to add weight.  The dampener is added to directly to the metal surface and transforms the sound waves into heat.  Thus an integral part of a good sound dampener is a layer of metal foil that helps keep the heat from entering the vehicle.

The second key function is sound absorption, a barrier to collect the sound waves that are generated both inside and outside the vehicle.   This is what is done by the  baffles one sees on the ceilings of in orchestral halls.  Baffles are not terribly practical in your car, so this function is usually performed by a light, open cell foam.  This is applied on top of the dampener.  And that is about it.  That is most certainly an overly simplistic description of the basics of vehicle soundproofing, but it helps to set the stage for the story of our product scanning and  eventual selection of a product.  There is a great variety of products available, some which perform one or other of the functions, or perhaps combine them both.  All the sellers say more than one layer is better, which no doubt helps to sell sound proofing material.

The first supplier that we became aware of is the aptly named Noisekiller(NK) of Great Britain.   NK makes sound reduction materials for every imaginable application, including but certainly not limited to vehicles.  I became aware of them because they happen to produce custom “soundproofing” kits for Land Rovers.  The product is highly recommended by many others.  Thinking this might be the way to go last May I exchanged emails with Andy, my contact at Famous Four, who said he could get NK to send them a kit which they could send on to me as part of  my star-crossed third shipment (see separate “Customs Shock” post).

However, at this point I encountered the problem that would make getting sound proofing to Ghana a real challenge: the weight.  The stuff is  expensive enough to begin with, but it weights as much as 1 pound per square foot, which rather renders international shipping costs prohibitive.   The NK Defender kit costs 280 British Pounds, or about $450, to buy, but the weight of that kit is 50 kilos!   Andy said he could get a 5% price reduction from NK to cover the cost of getting it to Famous Four, but for them to send it on to Ghana would be an additional (gulp) 430 British Pounds, or almost seven hundred dollars just for shipping, for a total cost of more than $1,200.   That is very expensive quiet.  I told Andy thanks, but I would have to pass.

That began a long search thither and yon for a less expensive noise reduction option.  Some Land Rover forums have people talking about assorted construction materials that are usually readily available in North American or European hardware/building supply companies, for example the ashphalt paper that goes under roof shingling, but that sort of thing is not necessarily available in Ghana, and would be very difficult for me to locate.  My local search did lead me to Ghana Rubber Products, which I thought might produce some sort of heavy rubber that would work.  They produce sheets of rubber of varying sizes for shoe soles (ie. flip flops)  This led to a Saturday morning meeting with the owner at the GRP plant in Accra, who showed me what they had.  They identified a 3 mm thick but not very heavy rubber that I thought might at least serve as a sound barrier for 30 cedies  ($20 dollars) for a 4×6 sheet.  At that price we could do the whole Defender for about $100.   I went back a week later and spoke to his brother who, incredibly,  happens to own a Land Rover Defender and had actually purchased NoiseKiller.   He knew something about  sound reduction and recommended Noisekiller, he was not confident the product I had been looking at would do too much, but he identified a slightly lighter material.  I bought four sheets worth of his flip flop sole material thinking I could use it as sound absorber for some areas, but left knowing I was still in the market for sound reduction material.

Other options I found included Genesis of South Africa and Second Skin or Dynamat from the US.      I spent a lot of time looking at Genesis,  because it seemed to be a good product reasonably priced.  They also have a liquid paint on product that one can apply inside or outside the vehicle, which extends the area that one can apply it to.  However, when  I eventually measured and got a quote on the material and shipping it was only marginally less than the NoiseKiller from Great Britain.

In the course of surfing the web for more ideas and sources I stumbled upon a company called B-Quiet, which sold dampener, absorbers, and combinations thereof and billed themselves as  “the affordable sound deadening solution”.   One of the things I noticed was their website gave prices in US and CAN dollars and I assumed they were an American company selling into Canada.  The $C=US$ exchange rate they gave was rather  unfavourable to the Canadian dollar, which would make an American product more expensive to Canadians, so in a patriotic mood I sent them an email to say as much.  I received a prompt reply saying they in fact were a Canadian company located in Alberta and they thought their exchange rate was just fine thank you.  Of course, if they are producing in Canada and selling to the States the low exchange rate only makes them more competitive with American products like Dynamat.  Brilliant.

I looked at this product more carefully and judging from reviews their quality was good and the price gave credence to their website billing as the “affordable sound deadening solution”.   I looked at something called  B-Quiet Ultimate, a sound dampening material, and V-Comp, a combination sound dampening and absorbing material.   They also produce B-Quiet Hiliner, a thicker aluminum lined acoustic foam for under the bonnet.  Similar materials  are available from Genesis or from Noise Killer, but the Canadian company’s price was much more reasonable.   I was able to get a quote  of $500 for an coverage area larger than NK or Genesis, delivered to Ottawa.

The Ottawa delivery is where the real beauty of this Canadian- sourced option plays out.   I have an annual mailing allowance from Canada of one hundred pounds, which might not go far if you have a large family or get lots of magazines, but this year Laura and I have only used 25 lbs.  It is now October and we have more than 75 lbs of  shipping we have to use before the end of December.     As it turns out the weight of two 50 sq. ft rolls of B-Quiet Ultimate and two 15 sq. ft. rolls of V-Comp is about seventy pounds – the Hiliner only weighs another pound.   I could use more V-Comp but if we go over our weight it will just be held in Ottawa till next year.  I can order more then if I really need it.  I am planning to combine the B-Quiet Ultimate deadener with the V-Comp in the particularly vulnerable areas in the front of the cabin until the V-Comp runs out and  and then use pieces of the Ultimate  in combination with the flip-flop sole material from Ghana Rubber Products for less vulnerable areas.

B-Quiet products purchased: 30 sq. ft. of V-Comp barrier (1 of 2 rolls on the floor – 18 lbs); 100 sq. ft. Ultimate, (1 of two rolls on the table – 17lbs); and a 4×6 sheet of Hiliner for under the bonnet (silver on the right – 1 lb

It only took about two weeks to get here, and with this in hand I am ahead of the game because we can’t install it until after the painting is done, which won’t be for a couple of weeks yet.    With this material installed and covered by carpeting our  Defender will hopefully be elevated from clangy utility vehicle to relatively quiet cruiser.