14 replies to this topic

[Pavel]

A couple of days ago I received a PM from a member on here asking about how I deadened my mini for a modest cost with amazing results. I figured it might be beneficial to a lot of people so will post this here. Mods if you feel this should go in another section, please feel free to move it. Also, if you disagree with any of this, voice your opinions, if you have any of your own suggestions, feel free to put them in here so that others can benefit from it.

I would at this point like to point out that I have personally done this and speak from experience. I have also been in a whole variety of cars that I worked on from minis to micras to skylines to merc S600 (the w140 tank version), so have some sort of comparison.

I enjoy having a high quality sound system in my car. I would not class myself as an audiophile as I do not install multi-thousand pound setups and worry about setting them up to perfection; in fact I don't think I would be able to hear the difference. Nonetheless, I have a certain standard of audio that I like to enjoy.

In order to get the most of it and to make the mini more comfortable I thought I would ensure that I sound-deadened it prior to refitting the interior and fitting the audio system. Being on a budget lead to improvisation, and this is what I did:

I bought two big rolls of aluminium flashing tape. I don't know if it's the same in england (i did this in Cyprus) but it's basically bitumen-like tape with a silver foil on one side, overall thickness about 2.5mm. You stick it bitumen side down. The idea is that it is not fancy like dynamat, but forms a bit of a sound insulation barrier, and, perhaps more importantly moves the resonance frequency of tinny panels further down the frequency range, making them "quieter".

I laid a layer one the entire cabin floor, in some places doubling up. This was done on a 1990 Mini City, which had some sort of rubberised sound deadening in place (as in almost "painted" onto the floor, rather than something you can lift up etc. you'd have to chisel it off). I realise that older minis may not have this factory insulation and so you might have to increase the thickness of your own sound deadening.
in the boot, I put one layer on the boot floor, and a layer on the sides, the rear bulkhead, and the underside of the parcel shelf (this failed, but more about that later). I also laid it up on the cabin side of the rear bulkhead, on the inside of the rear quarter panels, the inside of the doors, the inside of the front firewall, and on the inner front wheel arches. In total, I think I must have spent about 60 Cyprus pounds (about 70 pounds sterling). I also laid my own carpet inside, for which I used a thicker carpet (bought from an automotive upholstery shop).

The results? AMAZING to say the least. That was quite a brief summary, but if I describe in a bit more detail there is room for improvement. The flashing completely eliminated panel rattles from all the bodywork. At first I got some resonance from the bootlid, but after putting a layer on it that disappeared. In terms of road noise, I reckon it eliminated a great deal of it. Unfortunately it does nothing to eliminate aerodynamic wind noise so on the motorway the air rushing past still made the same amount of noise, but the engine and road surface were significantly dampened. The doors closed much more solidly, and in general when sitting in the car you didn't feel like being in a tin can.

Now the bad points. The first thing that was obvious from installing this is that... there are a lot of things in a mini that rattle that cannot be cured with sound deadening (no matter what the cost of it.. even dynamat). You wouldn't necessarily notice these at first, but to give you an idea, here are some things that rattle/make noise due to engine vibrations or sound systems: Speedo (the biggest problem in my case), dashboard, window winders/handles, indicator stalks, wires (yes, wires can rattle against panels), the heater, door cards and pockets. For me the main problem was the speedo, and occasionally the dashboard and door cards. These need padding more than sound deadening, to stop them vibrating.

Next.. if I was doing it properly.. would I still use aluminium flashing tape? Absolutely... for the majority of the car... PLEASE READ THIS: aluminium flashing works very well for a budget solution, but NOT on vertical surfaces. I realise that Cyprus gets significantly hotter than most of the UK but I'd imagine that even on a cold UK summer's day, it would still fail. The reason is that the bitumen sticky side stops being sticky whenever it gets even semi warm. It unpeels itself from teh panel leaving a sticky black mess. Not recommended. I have had zero problems with it on the boot floor and cabin floor. However, it got completely unstuck on the boot-side of the rear bulkhead, as well as on the boot sides and parcel shelf, and the firewall. More importantly, as it got unstuck, not only did it leave a mess but it also was noticeable in terms of noise. Some things required it more than others.
The parcel shelf should be sound deadened from the top, no need for applying any of it from the boot side (I didn't do this as I had a rather securely installed MDF panel on top). The rear quarter panels don't actually need sound deadening in terms of vibration, but it does make a difference to rear passenger road noise. The front doors should be sound deadened, and you can just about get away with using flashing on the inside of the interior skin, as it will be prevented from peeling by the door card (make sure all your door card mounting clips are in good order as that is a major source of rattles). However, the majority of door noise is eliminated by applying sound deadening to the inside of the outer skin. This is fiddly and not as easy, and you shouldn't use flashing for this, but rather dynamat or ebay equivalent (even a little bit will do). Definitely worth it as I tried it and it does make a difference. While I don't have door mounted speakers the improvement in the feel and quality of door closing was worth it. If you have door mounted speakers, the effects are even better.
The fuel tank and strap definitely need deadining, and I just about got away with using flashing on the vertical surfaces by clamping it with the strap, so it was secure. However, I would still advise using dynamat. The rear bulkhead is surprisingly rattle-free in my experience, and will be okay with just a small application of dynamat or flashing on the cabin side of it. I had my subwoofer box bolted thorugh it (firing through a hole into the rear seat) so it added quite a bit of structure to the bulkhead, but even before that I didn't notice too much noise from it;
The front firewall needs a thick layer of sound deadening/insulation. I am not convinced that it needs dynamat, I think this is one of those cases where it needs quantity over quality. But make sure you get something that sticks well. What I did was I stuffed the entire cavity between my dash and the firewall with fibrous insulation stuff (not messy, it comes in sheets which look like random fibres pressed into one long fabric, with a polythene backing on one side, bought from DIY shop) to try and maximise deadening. This worked OKAY, but doing it next time I'd apply at least 3 layers to the firewall. A LOT of engine noise comes through this way. Dynamat would be preferable, but bloody hell, it would be expensive.
The bootlid needs insulation, and I can't fault flashing in this case, except that it once again got a bit unstuck!

So to summarise again, flashing works amazing on horizontal surfaces (works wonders on the floor.. double up on the exhaust tunnel), and works fine on inclined or vertical surfaces if there is some method of preventing it from coming unstuck. I have highlighted where I would recommend using a dedicated automotive sound deadening solution such as dynamat. If I was doing it myself, I would buy the ebay equivalent. Make sure to find the one that is the biggest thickness.. as 1mm of anything won't give you much insulation. I have tried dynamat on doors and it does work, but **** me, it is not THAT much better to justify that price. I think ebay sound deadening is relatively reasonably priced (i think I found some for 60 quid for a roll the other day).

Finally, I did NOT deaden my roof for one simple reason: I never saw the need to. I had a factory sun roof so don't know if that had any effect or not, but my roof never did cause any noise issues so I didn't bother taking off the headliner to deaden it. IF you decide to deaden the roof (and I would if I had a bare shell of a car), then whatever you do, please do not use flashing. Use some sort of proper sound deadening, and first CHECK THAT IT CAN SURVIVE UPSIDE DOWN IN HEAT, as it will ruin your day if it get's unstuck and drops onto your headliner.

Sound deadening does not need to be expensive, and more importantly, I think it's important to highlight that it is probably of greater benefit to the every day daily driver rather than to those looking to install a sound system. There will ALWAYS be noises in minis that are difficult (and expensive) to eliminate in terms of ICE sound quality. However, the increase in comfort from reduced road noise, simply from fitting flashing on the footwells and floor and boot floor cannot be exagerated. Sound deaden the doors and align your door slam plates and you will honestly smile each time your door closes with an almost German reassuring clunk.

I am not saying that my solution is appropriate to high level ICE installations (for reference mine was 5.25" Morel components up front in fibreglass underdash pods, a Pioneer 12" sub in a custom made sealed enclosure firing through the rear seat, head unit Pioneer DEH-P77MP, and a 4 channel Helix amp running the speakers and sub). Also, if you've got unlimited money, then dynamat throughout will probably do a better job, but it won't be worth the money you spend on it. However, for ANYBODY else doing a rebuild or refitting their carpets, spending 50 quid on a budget sound deadening will improve your car immensely.

Pavel

[Teapot]

Thanks for the tips on soundproofing on a budget - pointing out the pitfalls is very useful and there's no substitute for personal experience.

Edited by Teapot, 18 October 2009 - 11:52 AM.

[AndrewJ530]

Mods, i think this should be pinned in the FAQ.

Edit: In the technical (interior) FAQ not in the forum FAQ.

Edited by AndrewJ530, 17 October 2009 - 08:26 PM.

[captainjack15]

That's an essay!!!!

LOL

FAQ!!!

[mike.]

I actually need this info and was going to ask about it soon!

I'll be having a sub in my boot and speakers on the rear shelf. All i'm really bothered about is rattles and vibrations. My logic being, other noise i will drown out with more volume.

When doing the sound proofing for example on the bootlid, do you think a few smaller strips or patches of it would do to eliminate the majority of the vibrations?

Thing is you can get a resonable sized roll of dynamat for about £25 for a 32" by 18" roll. I was hoping i'd be able to do most of the rear area of the car with this by economising and just using strips and patches of the stuff. Because at the end of the day, it'll still prevent the vibrations travelling as far.

What do people think?

[Hekmat]

I have used e-dead on mine has made a great difference. I even used it on the roof and doubled on the bulkhead. One thing to bare in mind make sure you use a wall paper roller to realy push it down (what ever you are using) and make sure it is sticks. I had one strip of edead from the roof fall down since I did not use the roller and it got to hot, also I did not have the roof lining in place to hold it up.

2 Rolls of the suff (about £65) is more than enough to cover the whole car, have a look at my project page for pics.

[Pavel]

Hekmat, I think you've got the right idea, and thanks for highlighting the need to make sure it is properly stuck down and pushed down as hard as possible! I think the stuff you're talking about is what I would have used for the majority of the car, but in Cyprus it is impossible to get any sort of cheap sound deadening, only flashing or dynamat at silly costs.

Unfortunately it seems that emat also suffers from unsticking when it's hot... I imagine it is nowhere near as bad as flashing, but still appears to be a problem. When it unsticks, does it leave a black-ish mess, or can you just stick it back on? Also, keep in mind that the roof is the only place where you need to stick deadening on completely upside down.
The only thing I'd have to say about your post is that the headlining offers no support for any sound deadening on the roof, so whether you had headlining or not, it would have still fallen off and as soon as it unsticks, it stops being effective.

How thick is this emat? If it's relatively thin (1mm), then I'd still recommend using flashing on the boot and cabin floor, as it is thicker and offers more resonance deadening and sound insulation. Also, I assume you bought this emat from ebay... I would like to give it a try in my Micra as it is just as tinny as a mini is. Have you had any trouble with it coming unstuck on vertical surfaces like the bulkhead or side panels?


minimadmike, before you start doing anyhting, please rethink your setup. Will your sub in the boot be firing into the boot, or through the bulkhead and rear seat into the cabin? If you're firing it into the boot, PLEASE don't install speakers on the shelf. It won't sound very good, but more importantly, it will destroy your speakers very quickly as the subwoofer will be moving all that air while the speakers are trying to do the same. Trust me, the sub will win.

Secondly, if you're on a budget, I'd recommend using something like Hekmat sugested - emat. If you can afford to get one roll of dynamat, I'd put it on the sides of the boot and definitely on the fuel tank. The boot floor, and boot lid need quantity over quality I reckon to stop them from resonating, and for those two I'd suggest using a cheaper alternative so that you can get more of it on. I highly doubt you will be able to deaden the rear of the car with one small roll of dynamat.
However, if you insist on using that, then I suggest you don't cut it into strips but instead cut a square to stick on the side of the fuel tank, then two squares to stick on the sides of the boot (i.e. on the sides of the rear quarter panels just behind the lights), and then use the rest to put the rest onto the bootlid.
That way, when you want to buy more, then just stick some on the bulkhead, the TOP of the rear parcel shelf, and all over the boot floor:)

If you want are insistent on having rear speakers, AND a sub, I personally will suggest you fit some 6" coaxials under the rear seat. Run these off your head unit, and run your front speakers and sub off an amp. That way when you're alone, you can just set the fader to swtich off the rear speakers (they won't be improving sound quality to say the least!), and when you got mates in the back, then just turn them up from the head unit to get some rear fill.

Finally, anybody doing a boot build or even putting in boot liners, keep in mind that if you sound deaden the mini's panels and then install a whole bunch of flimsy mdf/plywood panels, unless these are properly secured and deadened too, they will make even more problematic resonance than your bare boot By the end I removed the MDF fake boot floor from my mini as it was causing too much resonance. The sides were made from 25mm MDF as extensions of my subwoofer box, so they were solid as anything and didn't cause problems. If you want it to look neater but aren't concerned about MDF boot suppoort panels, then I suggest you just get carpet and lay it, as that doesn't cause sound issues. If you DO want MDF boot panels, then use at least 18mm thickness, as it won't resonate.

Cheers

Pavs

[liirge]

Yer this would be good in the FAQ section!
Nice tips in there, Good work!

[mike.]

Well my speakers won't be in the rear shelf, they'll be on it, i.e. won't be sharing the same airspace as the sub. Also i'm going to fit some ports to the parcel shelf so the air has somewhere to go.

I've had speakers on the shelf before and they sounded fine, even if they were behind me, so i'm hoping adding a sub into the mix will just give me the extra bass i need. I've sat in a mini with speaker pods before and to be honest didn't really like how much room they took up. It'd be ok with 10cm speakers but the ones i'm using are 17cm, so would require pretty bulky housings.

I've got an amp to run the sub and speakers off. If i find i need more sound up front, i'll run some 10cm coax's off the HU.

Is this the sort of ebay stuff your talking about: Link

[Hekmat]

Hekmat, I think you've got the right idea, and thanks for highlighting the need to make sure it is properly stuck down and pushed down as hard as possible! I think the stuff you're talking about is what I would have used for the majority of the car, but in Cyprus it is impossible to get any sort of cheap sound deadening, only flashing or dynamat at silly costs.

Unfortunately it seems that emat also suffers from unsticking when it's hot... I imagine it is nowhere near as bad as flashing, but still appears to be a problem. When it unsticks, does it leave a black-ish mess, or can you just stick it back on? Also, keep in mind that the roof is the only place where you need to stick deadening on completely upside down.
The only thing I'd have to say about your post is that the headlining offers no support for any sound deadening on the roof, so whether you had headlining or not, it would have still fallen off and as soon as it unsticks, it stops being effective.

How thick is this emat? If it's relatively thin (1mm), then I'd still recommend using flashing on the boot and cabin floor, as it is thicker and offers more resonance deadening and sound insulation. Also, I assume you bought this emat from ebay... I would like to give it a try in my Micra as it is just as tinny as a mini is. Have you had any trouble with it coming unstuck on vertical surfaces like the bulkhead or side panels?
....


Pavs

Well, I had 3 strips on the roof and only one came off, basically looks like I was lazy and did not push it hard enough. The headlining rods should provide enough support so if one part comes off it does not allow the rest to fall off.

The eDead stuff is around 3 mm thick and once removed does not leave anything majorly behind, it leaves the glue behind on the edges and areas that have been cut. You can restick back on without a problem.

I have used in the boot (back of passenger seat) and side quarter panels and sticks and stays nicely.

I got them from here. They also have a new version called eDead Eliminator which is more expensive. 60sqft is more than enough for the mini.

Basically the areas that are covered are: Entire front (from bulkhead down to the center support), rear floor, roof, back of passenger seat, side wings and inside the doors. I did not bother with the boot floor or lid, since I am going to have a fixed MDF boot liner. If the noise from the boot gets too much then I will do the boot as well.

[richardsoniscool]

if this stuff stick and leaves a messy black residue, what about rust? you will neveer know if you have it? and then your sound insulation is insulating rust? or should you not have rust on the inside??? i have a small amount of surface rust which i will rub down and paint, but it will be back im sure.
thanks

[Nick Warwick]

I used eDead on my floor and read quarters and rear seat bulkhead it made a big difference, i want to do the front bulkhead now to reduce engine noise then the doors to have a nice thud noise.

I used 30 sq Ft of eDead and doubled up in some places

[Dog]

Carpet underlay did the job for me!

[Hekmat]

I think you find layering stuff is the best way, since different material will obsorb different types of sounds. I changed from carpet and the original butone stuff to, edead + underlay and carpet and it has made a huge difference.

[Nick Warwick]

if anyone wants to reduce engine noise get the felt that covers the bulkhead, it makes an amazing difference, good for if you like your music but still like the noise of the engine, i give the stuff a