Sound deadening a hardtop ideas

Dynamat. Done.

Easy to apply. Forms to curves. Deadens sound without covering the entire piece.

Ted

There is a Dynamat SuperLite version available too

Good call Ted. Dynamat. Get the lightest version, because David WILL be taking this on and off. Then apply some spray glue, I recommend 3M 90, not the 77. If you can get it, get some Alcantara from a trim shop if you can find it. Light, great wear, and good looking. But I don't think cheap.

 

http://www.alcantara.com/en/automotive/9/index.do

Thanks, Lads. I have the Alacantara here now. I'll look for dynamat and 3M90  locally tomorrow. Got the Alacantara from a dealer way down in the Southeast, USA. Good price and easy shipping to Canada. 

 

It's sometimes frustrating getting US products shipped to Canada. Le PIP came thru for me with my new Weber 32/36 a while back. Thanks, Danny.

 

I love shipping stuff whenever the chance happens to help people. Six months ago I shipped three crates to Paris, France...one Huosai radial engine, one prop to match and one SS exhaust system. Total weight was about 1,200 lbs...shipping cost was about $2,400, CAD Montreal to Paris. Montreal smoked meat is about the best and the ...ladies....right outa sight...!    or, completely in range if you play the price is right at the right place...........  ;-)

Agree on the Dynamat type products. Adding carpet pad over top of dynamat might help with some high frequency absorbsion but the density is really too low to be used by itself for damping the lower frequencies and panel vibration unless you use multiple layers which isn't practical on the roof.

Sounds like a good plan David! Can't wait to see it in person.

David.  I do have an IM padded hard top which I use in the winter.  Some sound deadening is needed.  But, I find that most of the noise with the hard top on comes from the inside of the car and the hard top acts to amplify the sound.  Fuel pump and tranny are most noticeable.  Don't know if you are doing a ground up restore but I would say the best way to keep the car quiet with the hard top on is to sound proof the passenger compartment.  Cheers.

I realize Dynamat is the peferred automotive sound deadener but can someone talk about why inch-thick foil-backed fiberglass wouldn't do? Pretty sure that stuff is easy to get (It's pipe wrap) super flexible, gluable and waaaaaay cheaper and lighter than Dynamat. Should absorb sound pretty good and insulate the top pretty well--both from sun-heat-in and heater-heat-out.

 

Or am I stupid?

 

(Don't be shy about telling me so!)

Nothing stupid in any idea, Ed...but 1 inch thick might have various disadvantages. Loss of headroom would be an obvious one but fitting a nice headliner over and around it might be a real pain considering you've got fasteners and a rear window to contend with.

 

Thanks for the other ideas, Lads. Phil...the interior is now done as far as it will be done. New carpet set and sound deadening under the floor pieces. If the worst I'll hear are the fuel pump and tranny, I'll be ok with that. The last and most feared sound would be ...........PHUCK...there goes the hardtop !

 

Mine is a low bucks older and rebuilt IM Speedster replica. I treat it as such and hopefully it will be looked upon in the same manner.

Fiberglass itself is a thermal insulator so it won't conduct heat. Spun as insulation, it slows air movement so it can't circulate and transfer heat. Makes it a good thermal barrier but it's too light for mass damping and not very good at stopping lower frequency noise because of low density and open-cell nature.

A rubber type product's main purpose is it's dense enough to add mass to the panel so the panel vibrates at a much lower frequency. And it's flexibility also absorbs sound vibrations internally.

Fiberglass is fine thermal insulation if you have a lot of thickness available, but a closed-cell foam rubber or bead-filled paint (lizardskin, etc) can be as effective as a heat barrier and much thinner too which makes them better for automotive use.

Given the ethos of David, I'd recommend killing two birds with one stone. Just get some glue-on headliner material and be done with it. It's got a foam backing, is cheap, and with some care can be installed to look reasonably good. Trimming the edges to not look raggedy is the trick, but I think somebody as resourceful as David could probably pull it off. I'm sure it'd cost less than $300 for everything.

Ya know, if bedliner roll-on stuff is available in the right color, that could be a one application ticket. Maybe?

 

Check out all these colors: http://www.monstaliner.com/for...nstaliner_colors.htm

 

David, what do you think about Jeep Spice?

I actually like that idea quite a bit. If I ever did another speedster, I'd use bedliner in LOTS of places.

Dynamat is probably the best sound deadener on the market. Their Super-lite is about half the weight/thickness of of any other product on the market with the same quality of sound deadening as regular Dynamat/Dynamat Xtreme. Suggested retail is $100 for a 12 sq ft kit. By shopping around you can find it often for much less from various vendors.

 

I did my entire '56 F-100 cab, including doors, floors and headliner 2 years ago with the Super Lite. I used 4 kits and still had a little left over. I obtained the Dynamat material from Rusty's Rods in TX for about $325 for 4 kits including shipping, the best price I could find at the time, it was on sale then. I used a DEI acoustic thermal barrier on the firewall I got from Eastwood at about 1/2 the cost of anywhere else.

 

Regular Dynamat, Fat Mat and similar products are thicker and heavier thus will add weight and since you will be removing the hardtop from time to time you'd want something light weight

 

Those are some pretty interesting products. I've decided to keep it simple and just install the Alacantara  foam backing vinyl that I have on hand now. The trick, like Stan mentioned, will be to fit up a nice edge around the perimeter.

Sound suppression is, ultimately, just physics, and justinh has the basics down correctly, IMHO.  Adding mass to the surface so it does not respond well to higher frequency input.  Lead sheet would be ideal, as it has weight and is "dead", which is to say compliant and has a high sound transmission loss factor -- almost zero rigidity.  High stiffness materials transmit sound very well with little loss -- think about folks putting their ear to a rail to tell if a train is coming.  Lead on the other hand transmits sound almost not at all.  When you really need it deadened, folks use lead -- in buildings for example.  Obviously, in this case, this would be outrageously expnsive, and add too much weight.  Bed liner (should I say tar?) likewise transmits sound almost not at all (has high transmission loss) and is fairly dense.  So soft and dense is the best, and while I have yet to examine Dynamat in person, i believe it incorporates these two qualities, and so it works.  Just aDDING A HEAD LINER, OR SOME LITTLE BIT OF FOAM AND A HEADLINER probably are not going tone the sound very much.