noise insulation

[Gabrielem]

2 hours ago, digifish said:

 

La función de las esteras de butilo no es desacoplar. Es húmedo, por lo que debe adherirse a las superficies metálicas. Es el mismo principio que poner la mano sobre la piel de un tambor y golpearlo en lugar de golpearlo sin la mano. 

 

Thok vs Booooommmmmmmmmmmmmmmmmmmmmmmmmmmmm

 

 

How's the car going after everything you did to it?

[Steviedakota]

On 04/06/2021 at 11:32, lukk said:

Hi Guys, 

 

I am starting to look into sound deadening my Superb and I hoped you'd help me with a few questions

 

• what works best or is a good enough solution for sealing the doors? I can see people using butyl matts over the outer skin to close off the interior of the doors. I also saw examples of people using VML. Is there much difference in the result? How is VML held in place with its high mass - tape, glue?
• when covering the car floor with VML - can I just lay it on top of the decoupler foam and tape the VML pieces together to avoid any gaps, or do I need to stick the VML it to the decoupler?
• do I really need the decoupler on top of the butyl tiles on the floor at all? I am looking to reduce road noise rather than getting a perfect result for music listening. I was thinking of using foam carpet underlay as the decoupler. It's 5mm thick and was branded as an "acoustic" product when I bought it
• finally - I live in Ireland and struggle to source VML. After Brexit the UK suppliers just stopped shipping here. Anyone knows where I could get it?

thanks!

 

My advice would be to buy quiet tyres first. This will improve things far more than just adding sound deadening.

 

Then if you want to further I found the biggest gains are found in this order:

 

B pillar

Boot floor

Under rear seat

Wheel arches

 

I've also done the following but not convinced I got any benefit:

Under bonnet

Inside rear hatch (then had to remove some as it was too heavy)

 

Doors are also tricky to dismantle and gains are questionable.

 

Good luck, it's an enjoyable process, but really, tyres first. 

 

 

 

 

 

[Gabrielem]

5 minutes ago, Steviedakota said:

 

Mi consejo sería comprar primero neumáticos silenciosos. Esto mejorará las cosas mucho más que simplemente agregar amortiguación de sonido.

 

Luego, si desea avanzar, descubrí que las mayores ganancias se encuentran en este orden:

 

Pilar B

Piso del maletero

Debajo del asiento trasero

Pasos de rueda

 

También hice lo siguiente, pero no estoy convencido de obtener ningún beneficio:

Bajo el capó

Escotilla trasera interior (luego tuve que quitar algunas porque era demasiado pesada)

 

Las puertas también son difíciles de desmontar y las ganancias son cuestionables.

 

Buena suerte, es un proceso agradable, pero en realidad, primero se cansa. 

 

 

 

 

 

Thanks for comment. I'm also going to do what you say.

The B-pillar with high-density foam seats, right? it can be done with Kaiflex. Noico butymeno or similar?

[Warkman]

To reduce NVH you would need to add bitumastic type acoustic pads to the floor, inner wheel arches, transmission tunnel and front bulkhead.

Then add thicker carpet to the cabin. 
that will reduce the noise transfer. 
does the L&K have more sound deadening? What about Audi? Could you cannibalise their padding?

[digifish]

2 hours ago, Gabrielem said:

The B-pillar with high-density foam seats, right? it can be done with Kaiflex. Noico butymeno or similar?

 

Just go to the local foam shop and buy a slab of high density closed cell foam - 5 cm x 50 cm x 50 cm would be more than enough. 

 

The stuff they would use for a seat on a bus.

 

Most shops have lots of offcuts they will probably sell you by the bagful. 

[Steviedakota]

2 hours ago, Gabrielem said:

Thanks for comment. I'm also going to do what you say.

The B-pillar with high-density foam seats, right? it can be done with Kaiflex. Noico butymeno or similar?

 

This is what I did with mine.

[Steviedakota]

Really important to fill the voids where the B pillar meets the cill with closed cell foam. We have two Superbs in the family and my wife's has the noticeably more noise at ear level than mine after sound proofing.

[Gabrielem]

I have found this that I think insulates more than the foam of the couches ...

 

https://www.leroymerlin.es/fp/81905360/aislante-acustico-copopren-12-db-40-mm-2000x1200x40#fichaTecnica

 

It is also fire retardant ...

 

Could it be worth it?

[lukk]

12 hours ago, Steviedakota said:

 

My advice would be to buy quiet tyres first. This will improve things far more than just adding sound deadening.

 

Then if you want to further I found the biggest gains are found in this order:

 

B pillar

Boot floor

Under rear seat

Wheel arches

 

I've also done the following but not convinced I got any benefit:

Under bonnet

Inside rear hatch (then had to remove some as it was too heavy)

 

Doors are also tricky to dismantle and gains are questionable.

 

Good luck, it's an enjoyable process, but really, tyres first. 

 

 

 

 

 

Thanks Stevie. Unfortunately my tyres are pretty fresh so I am stuck with them for at least a year after which I will try to swap my alloys for a smaller diameter.

 

I already did the boot, the B pillars and the two front doors over the weekend. I put Noico on the resonant panels and in the cavities I stuffed rolled carpet underlay with bags of rolled mineral cotton. The B Pillars are very easy and a very low hanging fruit.  For the boot I uncovered the trim up to the rear wheel arches so it was a fair amount of work learning how to take everything out, a lot of surface to cover with butyl and to put it all back. There is really a lot to cover behind the trim, many flat thin metal panels.

 

The doors are on the harder side for a first timer with all the clips and connector.

 

After all this work I do hear a difference, the car isn't annoyingly loud anymore and I can much less hear the noise from the side, like the passing cars. Also conversation is now much easier. 

On a coarse stretch of an Irish Motorway I register around 73-74 decibel when driving 120km / h. Still too much for my liking.

 

It's also clear that now nearly all the noise is coming from the floor and the wheel arches. Hopefully tomorrow I will have all materials to do the rear wheel arches from the outside and once this is done will be able to report on the improvement in decibels. I also managed to order the MLV and it should be with me in a week or two.

[lukk]

16 hours ago, digifish said:

 

The function of the butyl mats is not to decouple. Its to damp, and so needs to be bonded to the metal surfaces. It's the same principle as putting your hand on a drum skin and hitting it vs hitting it with no hand. 

 

Thok vs Booooommmmmmmmmmmmmmmmmmmmmmmmmmmmm

 

 

Hi Digifish, my question was not in regard to butyl, I know that it's role is to eliminate the vibrations. My question is why people put a decoupler, usually closed cell foam, over the butyl and under the MLV. Why is this layer there and does it need to be stuck to either one, butyl or MLV. Or can I just put it on top and cover with MLV hoping that it's high mass together with the carpet and matts will keep stuff in place.

[Steviedakota]

What wheel size do you have and what tyres are on them?

[lukk]

8 minutes ago, Steviedakota said:

What wheel size do you have and what tyres are on them?

 

Goodyear Eagle F1 Asymmetric 5 235/45 R18 98Y XL, MFS - whisper quiet on smooth surface (e.g. motorways in France) but extremely noisy on Irish roads which are made of coarse asphalt ofted with bits of stones. I think going down to size 17 and perhaps a bit narrower tyre would help

[lukk]

1 minute ago, lukk said:

 

Goodyear Eagle F1 Asymmetric 5 235/45 R18 98Y XL, MFS - whisper quiet on smooth surface (e.g. motorways in France) but extremely noisy on Irish roads which are made of coarse asphalt ofted with bits of stones. I think going down to size 17 and perhaps a bit narrower tyre would help

I just realised you are in Ireland too. I am based in North County Dublin btw

[Steviedakota]

10 minutes ago, lukk said:

I just realised you are in Ireland too. I am based in North County Dublin btw

 

Yup, north Wicklow.  I have 17 s with 68 decibel tyres, 215 55 R17, car is very quiet on nearly all surfaces. Will be interesting to see if your exterior wheel arch insulation helps.

Edited 7 June, 2021 by Steviedakota

[digifish]

4 hours ago, lukk said:

Hi Digifish, my question was not in regard to butyl, I know that it's role is to eliminate the vibrations. My question is why people put a decoupler, usually closed cell foam, over the butyl and under the MLV. Why is this layer there and does it need to be stuck to either one, butyl or MLV. Or can I just put it on top and cover with MLV hoping that it's high mass together with the carpet and matts will keep stuff in place.

 

It's a high frequency absorber. Would drop the noise levels a dB or so. The more layers you can add the better the result I suppose.

[digifish]

10 hours ago, Gabrielem said:

I have found this that I think insulates more than the foam of the couches ...

 

https://www.leroymerlin.es/fp/81905360/aislante-acustico-copopren-12-db-40-mm-2000x1200x40#fichaTecnica

 

Could it be worth it?

 

Given you would only need one slab sure. It looks to be even higher density full of glue and a mix of chopped up foams

[lukk]

6 hours ago, digifish said:

 

It's a high frequency absorber. Would drop the noise levels a dB or so. The more layers you can add the better the result I suppose.

do I need to stick it though to either the tiles or the MLV or can I just place one on top of each other?

[lukk]

Could any of you guys provide me with some noise readings from your cars at 120km/h with a note whether it's on a smooth or coarse bit, what tires you have was done on your car?

 

I know this will depend a lot on the tires etc but it would still be interesting to know. 

 

I am getting 73-74db on a coarse stretch and have done the fool boot with Noico (also behind the panels on the side), front doors and B pillars.

I am using a free iphone app called Niosh SLM created by National Institute for Occupational Safety and Health. It was found to be the most accurate of app in a test I found on the internet. It has no adds and offers a function to record stretches of noise. I can fully recommend it after using two other rubbish apps so if you could use the same stuff to measure it it would be great.

 

Also has anyone filled the cavity in the pillars C right under the tail gait? It seems entirely empty, at least on top,  is very resonant and there are small rubber plugs covering an entry to it.

Do I risk much by spraying self expanding foam into it? Would anyone know how the rear lights cabling is laid? I'd think it would be at the same level as the lights. 

 

Pic of  hole leading to it below

[Steviedakota]

Is that App on Android, I don't see it in the Play store?

[lukk]

3 minutes ago, Steviedakota said:

Is that App on Android, I don't see it in the Play store?

Just checked and no it isnt. This government agency stated that due to variety of android devices (different microphones etc) they are not able to create a reliable enough app. which is good as it shows they take their stuff seriously, but also bad for those without an iphone. Perhaps you have an ipad? 

[Gabrielem]

it would be nice to be able to use the same app all over the world ...

[lukk]

I can investigate what android app is suitable, there is some way to calibrate them but will need to look into it later

[Steviedakota]

So many variables I doubt you'll get a meaningful result unfortunately. I just tried 2 Android apps at ambient room sound and there was a 10 decibel difference between them!

[lukk]

4 minutes ago, Steviedakota said:

So many variables I doubt you'll get a meaningful result unfortunately. I just tried 2 Android apps at ambient room sound and there was a 10 decibel difference between them!

what are the apps names? yeah there are many rubbish ones out there so its disappointing that Niosh app is only on iOS

[Steviedakota]

I was tempted to inject expanding foam into the sills to stop sound travelling along them. I was concerned though that I might be interfering with cables or water drainage. 

 

If you are thinking of using it, I would inject it into a plastic bag placed in the area. This means it won't actually stick to the car and you have a chance of removing it if required. I would say it would make a very effective sound killer.

 

Another consideration, though very unlikely, is if the car ever needed body work in the affected area the expanding foam could make the repair more difficult.