New carpet, soundproofing, and dynamat - any tips?

[Farrar]

I haven't done this yet but it's on my "to-do, eventually" list, so thanks to Mark Vanyo for all the excellent and informative photos!

Farrar

[john 05141]

I have done more or less the same, but you went into far more details behind the seats. Looks very good, well done.
btw; I loved the expression "overpriced" Dynamat, right on!

John

[DMC3165]

A friend of mine did my wife's (then girlfriend) Lexus with dynamat when we put a system in it a few years back. That stuff was dreadful. Once its in it never comes out. Plus its heavy messy and yeah on a hot day it had a tenancy to ooze a little. The dealer gave us such a hard time when the lease was up (i advised against using it in the first place, but like most women she just did it anyway). Don't know how it is now but i'll never use it again

[vwdmc16]

I purchased a huge roll of the off brand stuff from ebay for my z600 restoration and the remainder went in the front wells of the D, it isnt hugely quieter but i did notice less tire noise. im very pleased with how it went in the honda, however ive yet to drive it and find how good of a job its doing.

[TTait]

That was a fair amount of work, plus all the "while your in there" stuff I wanted to do at the same time.

One tip to file away - spray on interior adhesive has a way of getting on your hands. Before you start to use that or any other vaguely annoying adhesive, set a can of Pam out next to the kitchen sink.

Multiple times I had glue on my fingers and had to stop and clean up before things got out of (or stuck to?) hand. At first soap and water sucked. Finally with one particularly bad mess I sprayed with vegetable oil and rubbed vigorously, and the glue all dissolved. later it worked on super glue too (unrelated to the car). Oil up, then soap and water.

If anyone has any questions about the job - let me know.

Tom

[TTait]

And both road noise and engine noise are reduced. The stereo sounds better, but half of that is better speakers too...

[outatym2001]

Just wanted to add three more pictures to my post number 16 above regarding my sound insulation install I did a while back. The pictures speak for themselves.

[DeloreanJoshQ]

I will be doing this project after the first of the year.

I have a bunch of questions/comments, so please bear with me.....

1. This question was asked already, but never answered: Does adding sound deadener to the top of the center console area cause fitment issues?

2. Weren't the later built cars sprayed with undercoating on the fiberglass underneath the car? Wouldn't this act as a sound barrier as well and be beneficial if you carefully masked off any areas that the undercoating would cause future issues with?

3. Being lucky to work in business that has some options on sound-reducing material, I did some research looking at the below products side-by-side:

-http://www.jegs.com/i/JEGS+Performan...70500/10002/-1

JEGS 'Quiet Ride' Ultra Sound Deadening / Heat Barrier Kit.

- http://www.jegs.com/i/Dynamat/327/10455/10002/-1

Dynamat Xtreme Insulation

-http://www.jegs.com/i/Thermo+Tec/893/14720/10002/-1

Thermo-Tec Suppressor Acoustical & Heat Control Mats

All three measured very close in thickness with a micrometer and other than the foil design, looked nearly identical.

So it came down to price/area.

The Dynamat was way more expensive for less coverage. The Jegs actually came in second place. The Thermotech actually was the best bang-for-buck.

So I will be going with the Thermotech supersonic material to lay down first. Then I will put Hervey's kit on top of it. Am I supposed to glue all of the Hervey pieces on top of the first layer? Jim taled about a second and third layer to put on top of the dynomat/thermotech layer. On the areas other than what the Hervey pieces cover, what all would you recommend specifically(links/websites)?

Is there any benefit to putting any sound reducer under the headliner? I do not want to add any weight to the doors, so I understand that area is off limits.

I will be installing a new reproduction dash as well. i already plan on loading it with thermotech sound deadening material. Is there any other places on or under the dash that would benefit from the material to reduce front wheel/road noise?

Thanks for all of the help!

[Spittybug]

I'm no sound engineer so take these comments as those purely from a scientist and Delorean owner.

Being that the whole body tub has a degree of flex to it, it acts like a giant drum. Vibration from the road surface, wind and flex of the car makes the large surface areas of fiberglass vibrate and generate low frequencies. I have sound deadening material applied like many of us do, and while it certainly cuts down on road noise, engine noise and much exterior noise in general, the low frequency body tub noise is still present. I don't see how we can get rid of that short of stiffening the fiberglass. High frequencies are the most obvious and immediately annoying, so yes, getting rid of them is rewarding. The "drone" of the very low frequency tub vibrations are responsible for that tiring kind of noise that just wears you out over time....... Hard to fully put into words, but if you've driven a Delorean for any period of time I think you know what I mean.

That said, has anyone tried taking any other approaches to negating these low frequencies? Attaching stiffening braces on the fiberglass? Active sound cancellation (this screams for Bistsyncmaster's ingenuity to tackle)? Others? Stephen at DMCH and I were talking about this and he believes the new tubs they are making will be stiffer due to the improved materials and construction and should therefore be much less resonant. That would be nice indeed.

[outatym2001]

My unscientific answer to question 1.
No. I don’t believe adding sound deadener will cause any fitment issues. The eDead120 I used is about 1/8” (3mm) thick. So if you attach it to the fiberglass body under the center console you will raise the center console about 1/8”. Or just cut and remove the sound deadener around the threaded studs and this will allow the metal brackets under the console to lay against the fiberglass body like they were designed.

My unscientific answer to question 2.
I thought the later DeLoreans had a black undercoating on just the epoxy coated mild steel frame and not on the fiberglass tub.
The factory applied undercoating depending how thick and heavy it is I can’t imagine it does any sound insulating.

Answer to question 3.
My preference is on the material I mention in my posts 16 and 27.
As far as gluing down which layer first? I like the explanation given by
http://www.secondskinaudio.com/
1. Since vibrations can only be reduced when a damper is making full contact with the sheet metal, vibration damping will always be the first and most important part of any sound deadening project. (Example foil lined self adhesive sound deadener of your choice).
2. After treating the vibrations and structure borne noise with a sound deadener the next step is to block the airborne sound waves with a mass loaded noise barrier. (Example John Hervey’s neoprene noise barrier).
3. After the cars interior is properly treated with a vibration damper and a noise barrier, the last of the 3 steps is to treat the back side of your cars upholstery with one of our gasketing foams. (Example I personally used ¼” (7mm) white closed cell foam on the back of the carpeted pieces but first I ripped out the old cheap foam).

I don’t imagine there is much gain at all putting sound reducer under the headliner where it attaches to the fiberglass body. That portion has a hollow steel box glued on top of it which is hidden under the SS roof panel (T Panel).

First and foremost attach sound deadening inside the cabin on the surfaces where the four wheels are. They are the biggest noise makers. I put sound deadening all along under the carpets because the fiberglass sounds like a hollow drum when you smack it with you knuckle.
You only need sound deadening where the reverse side is outside of the car. Meaning you wouldn’t put it on the dash board because the underside is still inside the car. Put it where the outside noise is trying to get into the car ruining your driving experience.

It’s a lot of dead weight in a DeLorean with not much going for it unless you have an engine upgrade.