How nice can a Miata be inside? (hardtop, dynamat, etc)
 

I've always pulled the interior out of my Miatas.

Curious how much of a difference it makes to add a hardtop and sound deaden everything, is there a big change in wind noise? Does it feel as cramped as it usually does with the convertible top up? Still feel like a tiny tin box because it is?

a ton.

Does anyone have any proven results doing this? I'm curious about DB readings before and after, or just a well placed mic located in the same place while driving down the same road before and after.

My hardtop is a million times quieter than the soft top.







But my soft top leaks like a sieve so it might not be the best example.

I am 6'4" so I don't like the top up if I can help it but I don't find the soft or hard-top much different sound wise. The soft top frame can make noise if it's not lubed and dampened. I don't find either hard or soft top super quiet compared to my daily but when driving in another tin can such as a civic they aren't really far off IMO.

Hardtop is more quiet but not by a lot.

I will have a very solid before and after when I get my car running. I've gone the full monty on sound deadening...everything. Considering how loud the car was before, anything better, is totally worth it.

Do it right though.

Vibration deadening
closed cell foam
These two alone should be a big change

if ballah Mass Loaded Vinyl

Also check out the condition of your undercoating, it couldn't hurt to spritz on some new 3m rubber sound deadening in the wheel wells.

You have video of the before? Audio? dB readings? Need before after data!

I got a hardtop just because I now have frequent 4 hour drives to visit my parents. I got the hardtop on from a member in the middle of one of those drives and the different was very noticeable, but that's just from feel.

However, whenever I'm passenger in my roommates M3 my car feels like a dumptruck right after haha

I know 18psi did all this stuff to his "heavy pig" build, but I'm not sure he has measurable results. He can probably chime in.

The hardtop doesn't seem to create a noticeable difference when you put it on.

It's when you take it back off and use the soft top that you realize "holy CRAP, I can't hear shit because this damned soft top is soo loud."

That's real life.

the hardtop makes a world of difference with stock interior. Too lazy to find a better quality video but here is an example on the NC miata

Yup, that's what I'm worried about. Really want another comfortable car, but I don't want to get a third car, so this is an option I'm considering.

Can't imagine what it'd be like driving with the top up all the time. It's like a little coffin in there the couple times I've had to do it in the last year.

On my NA, the difference between the hardtop and soft top regarding interior noise was night and day difference. The car was much quieter and more livable and I was convinced the hard top really made the car livable on the highway.

Which was true, until I bought a nice NB. Honestly the difference between the tops on that car wasn't nearly as noticeable. For me, it's more of a toss up, the hard top is slightly better, but not enough for me to warrant keeping it on the car all the time. I mean, I own a convertible for a reason.

Just my experience though, but the differences between the two really are dependent on the car itself, IMO.

With a full interior, a factory hardtop is way quieter than the soft top. It's like the difference between a cheap little convertible and a cheap little car that's not a convertible. At least it can be if everything fits tightly.

I feel cramped under a ST, but (with a foamectomy) I feel comfortable under a HT. Again, if everything fits tightly and seals well, then it feels a little more like car that's not a convertible.

I've been slowly piecing together a '94 to be fun but comfortable.
I put sound deadening(peel 'n seal) on the doors, trunk, and floor; and there was a noticeable difference in the overall quietness of the car.

Now I'm working on hunting down every little rattle and squeak in the interior.

I think I did pretty much every single thing discussed here.
The improvement was quite significant, very big difference between my white car and the other NB's I've driven, but I don't have any data or numbers or whatever.

Its still no lexus, but it sure is nice.

There are some really good interior threads on clubroadster, about the only reason I visit there. We should have an interior section so I want have to go there anymore.

I am planning on coating as much of the interior panels with this stuff as I can before I reinstall carpet. Will try to get as much coverage on the interior of the doors and trunk as well.

https://www.parts-express.com/sonic-...-x-40--268-035

Yep, that stuff everywhere for sound reduction, and some dynamat in strategic locations to prevent vibration/tin can sound, and a hard top would probably be the 3 most effective things.

As soon as I get a chance to rip the interior out, I'm doing the tub with this stuff: Under Carpet - Sound Deadening Layer | Design Engineering, Inc.

I've got a dynamat type product on the rear shelf and vertical behind the seats. It wasn't any sort of miracle but it did reduce road noise quite a bit.

I'm not sure how many spots you'll be able to stuff 3/8" of that stuff behind/under. But if you somehow pull it off, I'd expect it to be deathly quiet and awesome.

I plan on pulling out all the factory padding. For whatever reason it all smells like ass so its not a hardship to replace it ;)

I replaced the vapor barrier on my doors with this stuff. Made the speakers sound a whole bunch better.

How much material does it general take to get maximum coverage in the miata? I am talking about everywhere including the trunk.

I ended up using just over 50sq/ft of dynamat, and I covered just about every inch of the inside and doors. everything except the trunk. Same goes for the foam stuff. Didn't see a point in doing the trunck since I completely blocked it off from the cabin, just seemed like a waste

There's loads of info out there on sound deadening, and it can be done for fairly cheap if you don't mind it being a little 'ghetto'. The best way to do dynamat is to only put on as much as you need since it only stops things from vibrating. The real quietness comes from the closed cell foam or mass loaded vinyl, which you want everywhere you can stuff it.

I know it's frowned upon to do things cheaply here, but I've seen people do roof flashing and yoga mats and the results were better then you'd expect.

We do cheap shit all the time. There is a difference between being cheap and being stupid.

I think something that would make the hard top more effective is adding some kind of layer between it and the car. I don't feel like the seals that come with it are sufficient enough. :2cents:

Nothing wrong with doing things on the cheap.

I happen to think that $50 for 50sq/ft of dynamat is reasonable.
Same for closed cell foam.

$100 bux and a relaxing day of straightforward work later, and you have yourself a much quieter and "plush" miata :)

I think for my car the main issue is squeaks/rattles, not the overall noise levels. I'm going to be extra careful when going back in with my new dash to make sure nothing can rattle, then maybe add some dynamat strategically to help the chassis. One of my main annoyances is actually due to the hardtop and my non-HT harddog bar, it loves to rub on the hardtop where the two corners are on the bar. I was thinking a proper foam or something, and then bolt the hardtop on SM style. Not sure on that yet, though.

A huge amount of the noise in my car with the top up is generated by the wind coming underneath the seem on top of the windshield. If I pull the top down really tight by hand while going highway speeds the noise cuts down significantly. I am not sure if beefing up the seals or tightening the soft top latches is the best way to fix this.

Hey, this is the place where we buy knockoffs of knockoffs of Honda IMs and weld them to the runners of the stock IMs rather than pay for a custom one. Just because we don't recommend AFPRs and other bandaids doesn't mean we're not cheap.

The seals collapse and/or lose some resiliency over time. There's a trick on M.net where you stuff some of that foam caulk backer rod into the hole. This makes it seal much more tightly, eliminating leaks and wind noise.

For me, the hard top on my NB reduces wind noise, but seems to make the engine noise more intrusive. That may just be that I can now hear the engine more with the reduction in wind noise :) I run the hard top in winter mostly for better rear visibility with the huge rear window. In summer unless it is raining the top is down so I have great rear visibility, but I hate driving with the soft top up.

Keith

I have to agree with this. I don't seem to get much noise from the trunk. The big magnaflow is extremely quiet and muffles sounds very well. The noise I'm encountering now comes from the engine bay. Anyone wants to chime on where to place some insulation to quite down the engine bay from the cabin?

I'm gonna pick "firewall for 500" alex

Well yeah, I guess what I would like to ask is if anyone has experimented on that particular area.

Firewall and trans tunnel as far back as your wallet will provide material to cover. I'll be using this: Floor & Tunnel Shield II - Heat & Sound Insulation 050501 | Design Engineering, Inc.

Kinda like what the 949Racing guys did with Crusher, but more:

https://www.miataturbo.net/attachmen...ine=1377575825

We have a thread about this actually: https://www.miataturbo.net/diy-turbo...t-cabin-74625/

Exactly as E02k said. I lined the transmission tunnel and also the drivers side I lined with koolmat, dynamat, closed cell foam, and MLV. I put real padding on the back of the carpet as well.

Should be damn quiet and hopefully no heat will be able to soak through it.

The hardtop makes a world of difference.

You don't need to add expensive dynamat all over a vehicle. Dynamat only reduces resonant noise in smooth panels. Using it for weight is silly.

Welcome to Sound Deadener Showdown | Sound Deadener Showdown

This guy used to have a breakdown of who made the best materials (which used to be SecondSkinAudio down here in Tucson) but now he sells his own product and his "less is more" philosophy. It makes sense, and would be 10x cheaper than dynamatting a full interior.

I would have loved to buy products from him in the past when I was doing my sound deadening, but after 5 emails and no response I got sick of waiting for him.

I had some leftover roofing matt material I'm applying to the floors & rear vertical. I've sprayed my fuel tank cover sheet metal in rockerguard and will be stuffing some Roxul under that cover and in the tunnel voids on either side of the tank. I completely coated my rear wheel wells with Herculiner on one side and rocker guard on the other (for rust proofing) so sound deadening should be a side effect of that.

I heard of people using the foil/bubble wrap product as well - has anyone here tried that?

Hardtop makes a huge difference on long highway drives and stereo noise is much better with it on. I also dyna matted the rear shelf and did not notice too much of a difference in noise reduction.