Soundproofing
 

Looking to add some soundproofing to my MY01 wrx to reduce road/tyre noise on motorway.

This place supplies an interior and boot kit for 145 comprising the following
Noisekiller UK - Car Soundproofing - Vehicle, Industrial, and Marine Sound Proofing

Has anyone used their kit and does it work well to reduce road noise.

They sent me the fitting instructions to get an idea of what's supplied. How long do you recon it would take to fit - how easy is it to get the back seat out and back in correctly.

INTERIOR SECTION

13 Undo the carpet kick strips by the door and lift the carpet. Slide this pad under the carpet in the driver’s side foot well.
14 This pad fits along the side of the transmission tunnel on the driver’ side.
15 This pad fits under the carpet in the passenger side foot well.
16 This pad fits along the side of the transmission tunnel on the passenge side.
Undo the bolts holding down the rear seat and lift the rear foot well carpets
17 & 18 These pads slide under the carpet in the rear foot wells
19 This pad fits under the rear seat. You will have to cut out for the seat belts.

BOOT SECTION


20 * This item adheres to the boot floor under the spare wheel.
21 & 22 * Remove the covering of the rear wheel arches and adhere these items to the wheel arches See Pad Section below before refitting the covering
23 This pad fits above the spare wheel and under the boot carpet.

PADS

Adhere 5 pads around the sidewalls of the spare wheel and on the front section of the boot floor.
Adhere 3 pads to the outer wing behind the rear wheel arches
Fit one pad onto the outer skin of each door

I'd prefer to drive it in and let someone do it all in a oner myself.

Let us know how you get on.

The back seat was not hard, i was charged about an hours labour to fit a new fuel pump, which required the back seats out.

Had this done by Noisekiller to my 01

they took just over an hour

Class job

What was the cost and how was the results?

I was gonna ask that - and who fitted it ?

Glad I got some sensible replies, I was expecting 'the noise is part of driving a subaru' lol.

Noisekiller did it themselves and it was a few years ago so I don't recall the cost although I did get SIDC Discount :D

Did it make a big difference to road noise ?

I have all the parts for the rear cost me £75 all yours for £50.Bought it from noise killer for a customer then he changed his mind.

PCM

I have a kit I bout from Litchfield to fit to my Spec-C Type20, but I changed my mind and won't be putting it in (too heavy and I like the car noisy)

It cost me £150, but I'm selling it for £75 if you're interested?

Full rear sound insulation including thick mats and dynomat -= all custom cut to fit a newage Scoob

Made a big difference

I have a v5 type R, do those of you who have tried think that noisekiller will be a lot better than just using rubber carpet underlay? i like the noise of the car, but its just a bit too much on motorway.. is it worth paying for a noisekiler kit as opposed to effectively free underlay?

Rubber foam underlay (the corrugated stuff) doesn't actually absorb much noise compared to materials designed to absorb it. Tyre noise is high frequency and tends to come in through the doors and floor - try driving with a door card off and it sounds like the door is open !

I haven't seen their kit but it should be a big improvement.

Exhaust noise is low frequency and mostly comes in through the floor of the boot area, again their kit should help. Much harder to stop it effectively due to the high energies involved, so the absorbing material mainly concentrates on adding some mass.

Best to go step-by-step, since each time you get rid of some noise you'll notice another one...

Thanks riccardo, what you say makes sense. The other option is Teklite, which can be found on ebay. You can get 37.5 sq ft for £85.. i wonder if this wold be a better deal than noisekiller.. at least this way you can choose where to put it.

I haven't seen any comparison of the two (TekLite and Noisekiller), have you?

The Noisekiller pads use different materials in different places as far as I know. Although it is a general solution it looks like a well-planned approach.

All the materials have different characteristics, it depends if the strategy is to stop a panel vibrating or to absorb high-frequency noise. Some exhaust noise comes in because the sheer amount of energy vibrates the panels under the boot and in the boot-lid or tailgate, so adding Dynamat or similar helps to damp the panels and make transmission harder. One of the Noisekiller materials is a foam sandwiched with a thin lead foil which is probably very good at this. The panel damping is also a good idea to avoid buzzes from bass if ICE is your thing. Some exhaust booming also comes in through the fuel tank under the seat, on mine it gets noticeably louder just as the tank gets nearly empty.

On the other hand tyre noise needs to be absorbed, and using Teklite (or Ensolite) in the doors, around the rear wheel arches and wherever else you can stick it then soaks up much of the 'whooshing' and 'roaring' of tyres on our noisy road surfaces.

(Talking of noisy roads, there is a road near me where a section of about 10 metres was replaced due to subsidence. Now driving over that patch the normal road noise cuts off like a switch was thrown, then back on at the end of the section. As a pedestrian it is even more noticeable, a car coming down the road is making the usual road noise, then utter silence, then back to normal. Why oh why can't they use that stuff everywhere ?)

thanks ricardo, and what you are saying makes sense. About the teklite stuff, i see that the same company sell the sound deadening edead stuff, which is 45mils thick. I thought this meant that it was 45mm thick, but clearly i was wrong, and it is only a couple of mm thick, so it is more like flashing tape. I was imagining it was like thick rubber pads sandwidged between aluminium.. anyway. so i really can't see how something that thin can absorb / block the exhaust / road noise. I understand how it loads the panels so that it increases their natural resonant frequency, but will this realy block low down noisy exhaust noise? ..... maybe noisekiller boot stuff is different, i just can't see it working that well unless it is relativelly substantial.. do tell me if i completely have the wrong end of the stick!!!

Cheers again

The eDead material is very similar to Dynamat, it adds a visco-elastic damping layer and some mass to resonant panels. That's enough to damp buzzes in doors from speakers, but not massive enough to help much with exhaust noise transmission. Dynamat Xtreme is a thicker version, it costs a bit more but is several times better at damping IIRC.

There are different problems to solve here, depending on what noise is the most annoying.

If a panel goes 'dink' or rattles or rings when you rap your knuckles on it then some eDead or Dynamat is a very good idea, although you don't generally need to put it everywhere, just the bits that go 'dink'. Door skins and the boot area are generally where speaker-driver rattles and buzzes occur. You don't need to put it on areas that sound dead when you rap them. These products don't really stop much transmission, but they help damp out vibration that might otherwise cause rattles and buzzes.

The foams have a different effect, in that they absorb sound waves that arrive from either side, mostly higher-frequency ones. The foams also give a little bit of mass-loading to a panel. Foams on the door skin and inside the door card help to cut other higher-frequency speaker-induced resonances, and absorb tyre and road noise that come in through the sides of the car. Foams aren't very good at absorbing low-frequency transmitted sound though.

If there is high-energy sound or vibration (like from the exhaust) then something heavier works better, like the foam/lead sandwich stuff, but that's much more expensive. Matting is often too thick or unsightly to use except under existing carpets or under the rear seats.

There is also a situation where excessive use of sound deadening can actually transmit low-frequency sound by bridging two surfaces, like in the Forester tailgate if it was 'overstuffed' with deadening (been there, done that !)

In a different thread I also suggested experimenting with the air-vent that is in the boot area, it gets a lot of noise from just under the bumper next to the exhaust. There is one vent each side, and certainly on a Forester stuffing something into the cavity to block the exhaust-side one makes a huge difference to the exhaust drone in the cabin.

I'd start with the Noisekiller kit and then assess what else needed to be done. If you want to do it objectively then using a laptop to record a WAV file driving along a particular road at a particular speed can be useful, because then you can compare the before and after and even use some free sound analysis software to see the spectral distribution of the noise. (best to get someone else to operate the laptop though !) Note that the tyre noise can vary a lot with temperature.

Thanks again for your advice. Because i'm (at the moment) just trying to absorb the low frequency high power exhaust sound, it seems that i need something quite thick. I'm sure Noisekiller will do it, but I'm looking for a possible cheaper alternative. Do you think it's worth using something like this:?

UK manufacturer - car SOUND PROOF MATERIAL carpet underfelt soundproofing & felt sound proofing

I'm more interested in the high frequency noise from road/tyre noise as the scoobysport box noise is quite low in comparison. I'm starting off with noisekiller in the boot, spare wheel well and rear arches to see if that gives any noticable reduction. If it does then would the next step be under carpet in driver/passenger footwell or inside door skins ?

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