Post-dynamat quietening

[chylld]

Heyas

Last weekend I finished dynamatting my 06 civic (http://www.ozhonda.com/forum/showthread.php?t=44356) and i'm looking at moving forward with further silencing. the car still isn't as quiet as i'd like, on rough roads i would only call the noise level borderline acceptable.

$600 of dynamat has done a number of noticeable things:

reduced overall noise level slightly
sharp bumps at low speeds MUCH quieter
sharp bumps at medium-high speeds slightly quieter
reverberation from high gear acceleration greatly reduced


Observations:

Noise level increases proportional to road speed
noise level extremely dependent on the smoothness of the road surface
engine noise is a relatively insignificant factor atm
wind noise audible
cars passing by on the other side of the road very audible


Given the above, i've deduced the following plans of action:

(plan a) change to quiet tyres (Yokohama v550)
improve on door seals
replace factory fluff under carpet with acoustic foam/barrier
sound deaden the firewall


the problem is that all the options above are fairly expensive, except for #2. one thing that i found was that the door seals are extremely flimsy, and between the 2 seals on each door there is a sizeable gap which I think is a nice place to start tackling the noise problem. i've put 6mm thick foam tape on the door in these sections on the right-hand-side doors, will be interesting to see how much benefit they give - however i'm not expecting great results.

questions i'd like to ask you guys:

do you think the dynamatting was effective? (given that i used 3 boxes of the 'xtreme' stuff)
any hypotheses as to why my car is still so noisy, based on my observations above?
which plan of attack will be most effective?

[aaronng]

Dynamatting should be effective to cut down noise caused by vibration. But noise caused by resistance from air and the tyres won't be affected as much by dynamat. Try C.drives!

[chylld]

hmm just had a quick look, i like how yoki says "The critically acclaimed C.drive exhibits an asymmetrical tread design that not only benefits from the silent technology of the AVS dB decibel..." but if you look at their graph:

http://yokohama.com.au/img/matrix_passenger.gif

it's most probable that the v550's are quieter.

[CTR Coupe]

Sounds like tires and door seals are the biggest issues at the moment. Wind noise when passing cars is usually door seals and road noise sounds like tires.
Honda is known for not putting enough sound deadening in the car usually to try to keep the weight down to improve acceleration and handling. Was a complaint on the 06 civic euro hatch as well too much road and engine noise.

I wouldn’t worry about replacing tires till you have worn out your current set

[aaronng]

Wow, what's the difference between premium and economy though... price? C.drive is actually high performance street tyres. It replaces the old Yoko a539 that people like for the performance. So v550 would be quieter.

[Fizz]

get a set of ear plugs! :p did you try dynamatting the roof? i would think covering that area should reduce wind noise slightly. yes get the V550 tyres, i've heard they're pretty good in reducing road noise :thumbsup:

[aaronng]

I think most of the wind noise comes via the side windows and rubber seals.

[chylld]

dynatting the roof would be a good path to take, and i'd do it but i don't know how to take the roofliner down properly - it's dangerous because of the curtain airbags. i'm sure there'll be a noticeable benefit though, it's the biggest flat surface on my car and it vibrates like crazy! i'm thinking of starting a thread asking for anyone who works at a sydney honda dealership/service dept, and arrange for them to take the headliner down for me, i do my thing and then they put it back up...

i drove to work with the right doors 'sealed' with 6mm thick open-cell foam tape and i didn't notice any difference at all. the gap in parts i think is larger than 6mm... might try some of the thicker, black closed-cell foam stuff. road noise leaking in through the lower door seals would explain a lot of the noise i'm hearing.

[JasonGilholme]

Maybe you should do your windows!!!

You're always gonna get noise mate. Theres no way you're gonna remove all of it.

I just hope that you double check when you're changin lanes because by the sounds of it, you won't be able to hear anyone else on the road around you.

I'd prefer to be able to hear someone comin up next to me rather then drive in a padded up tin can.

[Zilli]

Dynamatting should be effective to cut down noise caused by vibration. But noise caused by resistance from air and the tyres won't be affected as much by dynamat. Try C.drives!


agreed, this is why high end audio buildups use products such as dynamat because it reduces sound corruption caused by reverberatory (i think i just made that word up) noise, ie vibrations in doors, tunks etc.

the noise created by tyres, road noise, and other general NVH (noise vibration harmonics) issues are flaws of the vehicle.

i'm sure with a lot of time and money you can get rid of this, but the money you might have to spend might be better put towards an IS200 or something of the like

[chylld]

JasonGilholme: i'm not really aiming for dead silent - i'm aiming for the same or slightly lower noise level as the accord euro. one justification for this project would be that i don't want to have to turn the volume up when i hit a coarse road! :)

dead silence isn't possible and i wouldn't want that either; i guess you could say i'm trying to achieve at least some of the sense of isolation you get when you close the door in a luxo car.

Zilli: buying a second hand IS200 was something i actually considered, but i find the civic's interior much more pleasing. the acoustics of a car are much easier to deal with than the visual design! :)

[Zilli]

hehehe

this is true mate

good luck and keep us posted

[BLKek]

What if you make it so quiet you can't hear emergency vehicles???

[chylld]

What if you make it so quiet you can't hear emergency vehicles???

that's a very valid question, there was an article about how emergency vehicles are hard to hear in modern luxury cars. i don't intend to get it to that level though - the sounds of cars passing by don't bother me anywhere near as much as plain old road noise.

time will tell of course :)

[Captiva_Blue]

Just a thought... A large proportion of the wind noise in any car is generated by the door mirrors. The mirrors on an 06 Civic are quite large and don't have an especially aerodynamic shape (they taper to a forward point but especially around the post area, the design is very large, blunt and messy).

http://www.honda.com.au/wps/wcm/resources/image/468e4940a48fa565/car_civicgalleryext07.jpg

It's an exy option, but consider switching to a smaller mirror or one with a cleaner post design, that will cut down a lot of wind noise... same goes for things like roof-racks, weather-sheilds and that, it all creates messy airflow around the car creating more noise...

[BLKek]

lol, I know some luxury cars use sand in body cavities, looks like you'll be heading to the beach soon....