sound deadening question?

[Tiki Des]

i'm thinking about using sound deadening on the fibreglass body of my model A modified project. it's an open car, so will there be any benefits like quieting down panel drumming, road noise etc? if i go this route then i'll use Dynamat superlite as i've been offered 12 sheets (18" x 32") at cost. anyone got any thoughts, opinions or experience for my usage?

[Brizey]

I`ve no experience with Dynamat but if the offer is there for buying some, go for it Des.
My roadster has a rumble seat which isn't fitted for the most part (convenience of carrying stuff etc), but there is a noticeable difference in quietening body panel drumming when the seat/upholstery panels are fitted. Having said that, with the top down, the in car noise drops considerably anyway and if you are going to fit an exhaust system with any amount of `noise` this could cover any body/road noise!...

[rem]

Does fibreglass suffer from drumming? Most street bodies are pretty thick, and if it is a modified I suspect you'll get more wind noise than road noise?

[Happydaze]

When we had the 'glass '37 cabrio with the removable carson top (solid - made of 'glass) we didn't have much in the way of soundproofing. It was quite noisy with the lid on and really quiet with it off. Not sure what that tells us! Maybe the sound just passed by us? It seemingly wasn't wind noise, although there muct have been some with the lid on.

My 32 roadster, again 'glass, has Dynamat as a heat reducer. It made it quieter too I think. That might just because there's more stuff to shield the noise? do wish I had a cowl vent though. In very high temps the lack of air circulation in the footwell (in a roadster? - yes) can make it uncomfortable. Like Brizey says, this car is much quieted when the trunk is loaded.

Seems that aftermarket solutions have improved. The tar type stuff with foil prevents drumming and heat transfer, to which dense foam is added which adds the sound insulation. I'm guessing that's the Superlight that's been mentioned?

Chris

[Tiki Des]

Does fibreglass suffer from drumming? Most street bodies are pretty thick, and if it is a modified I suspect you'll get more wind noise than road noise?

almost any panel will resonate/drum, steel would be a higher tone, fibreglass lower. think of guitar strings, thicker the string the lower the tone. they're still resonating. for me it's a case of 'how much difference would it make'? as the body has no trunk and in it's place is a flat-ish panel, the doors are the same-ish but with more of a curve to it so i'd like to be happy that no panels will 'drum'. i'm not 100% sure but i have a feeling that i saw sound deadening mats glued on the inside a couple of panels of a Lotus? so many years ago and it was fleeting glimpse so i can't be sure???

this quote taken from Dynamat's website: As your vehicle drives down the road the sheet metal or fibreglass panels resonate, as you drive faster the panels create more noise......

they would say that though............ :rolleyes:

[Tiki Des]

thanks Brizey for your thoughts.

thanks Chris. i've now bought the Dynamat! too cheap to resist! the superlite is only 2mm thick so i shouldn't gain too much weight.

[pistolero]

The superlite is no way as quiet as the regular stuff...I know because I have it in my Forty. It was designed really for race cars. We sell the regular all day long and it works a treat.

[MisteR Tee]

When we had the 'glass '37 cabrio with the removable carson top (solid - made of 'glass) we didn't have much in the way of soundproofing. It was quite noisy with the lid on and really quiet with it off. Not sure what that tells us! Maybe the sound just passed by us? It seemingly wasn't wind noise, although there muct have been some with the lid on.

My 32 roadster, again 'glass, has Dynamat as a heat reducer. It made it quieter too I think. That might just because there's more stuff to shield the noise? do wish I had a cowl vent though. In very high temps the lack of air circulation in the footwell (in a roadster? - yes) can make it uncomfortable. Like Brizey says, this car is much quieted when the trunk is loaded.

Seems that aftermarket solutions have improved. The tar type stuff with foil prevents drumming and heat transfer, to which dense foam is added which adds the sound insulation. I'm guessing that's the Superlight that's been mentioned?

Chris
My old T-bucket was quieter with the top down but mostly due to the exhaust tips being about ear level! even putting turn-down tips on them didn't do much, but put the top up & the increase in noise was very noticeable. When I first got the coupe the exhaust resonance was incredible as the pipes were virtually straight under the car with no bends, so much so that I quickly had a complete new exhaust system made & fitted with lots of bends in it which did the job.

[randrhotrodimports]

Not got any in my 32 Coupe no excess noise at all to be fair, i guess the interior helps drown any down

My old T-bucket was quieter with the top down but mostly due to the exhaust tips being about ear level! even putting turn-down tips on them didn't do much, but put the top up & the increase in noise was very noticeable. When I first got the coupe the exhaust resonance was incredible as the pipes were virtually straight under the car with no bends, so much so that I quickly had a complete new exhaust system made & fitted with lots of bends in it which did the job.

[Tiki Des]

The superlite is no way as quiet as the regular stuff...I know because I have it in my Forty. It was designed really for race cars. We sell the regular all day long and it works a treat.

i paid just over a third of the RRP so i'm not gonna complain. it should meet my needs. isn't the Dynamat Xtreme dearer than the Superlite anyhow?

[yjohnb]

Used it in my GRP 34 and the difference before and after was noticeable.
Just have to make sure you roll it down well.
Cheers
John


Sent from my iPhone using NSRA mobile app (http://r.tapatalk.com/byo?rid=94507)

[Happydaze]

i paid just over a third of the RRP so i'm not gonna complain. it should meet my needs. isn't the Dynamat Xtreme dearer than the Superlite anyhow?

Speaking from total ignorance (never stopped me before! :) ), are you talking about comparable / interchangeable products, as you appear to be doing? Not sure but Xtreme is the bitumen-esque stuff (right?) but Superlite is ????? and not necessarily looking to do the same job???? Like I said, ignorance, and laziness - I could just go and look it up, but....... :). Enquiring minds with a job to do in the foreseeable need to know! :)

Chris

[Brian Eddison]

i didn't use it in the willys des, but our transit day van is full of the stuff, its not the dynamat version but does the job, every panel I could stick it on the inside of got it, does make for a quieter drive :thumbs_up_smiley:

[Tiki Des]

Not got any in my 32 Coupe no excess noise at all to be fair, i guess the interior helps drown any down

when i was built my i pop i drove it at first with no interior panels except the door cards, once i put in the rear seat and other trim i couldn't believe the difference! my pop had a bitumen type stuff painted on the inside of the rear quarters and doors from the factory.

[Tiki Des]

Speaking from total ignorance (never stopped me before! :) ), are you talking about comparable / interchangeable products, as you appear to be doing? Not sure but Xtreme is the bitumen-esque stuff (right?) but Superlite is ????? and not necessarily looking to do the same job???? Like I said, ignorance, and laziness - I could just go and look it up, but....... :). Enquiring minds with a job to do in the foreseeable need to know! :)

Chris

i'm using dynamate superlite which is 2mm thick, where as the dynamat xtreme is 4mm thick. both as far as i know is the same material, just a difference in weight and obviously a difference in performance. both are bitumen type stuff. there are other makes on the market, fat mat, silent coat, etc which are cheaper and probably just as good.

[Tiki Des]

Used it in my GRP 34 and the difference before and after was noticeable.
Just have to make sure you roll it down well.
Cheers
John

Sent from my iPhone using NSRA mobile app (http://r.tapatalk.com/byo?rid=94507)

cheers John, i'll be giving every panel a good clean before sticking it on.

[Whiff]

I thought you used Robin as sound deadener in all your cars Maurice!
Whiff.

[Brizey]

.... do wish I had a cowl vent though. In very high temps the lack of air circulation in the footwell (in a roadster? - yes) can make it uncomfortable.
A cowl vent is a god send in a roadster Chris, as you say, the footwell area can get pretty uncomfortable on hot days so every bit of ventilation helps!...