Outer Door Skin Worth Sound Deadening? Before and After Decibel Testing

[@K03sport]

first problem is you are going for 100% coverage of the metal area w/resonance deadener (50% is more than enough to kill resonance). second one is doubling the layer(s). Yes, you stated doubling was a much lower return of effort (essentially a waste). you need sound blockers (closed cell foam and mass loaded vinyl (which looks like it is in the works)

[@LimitLess-545]

Love the vid, aside from the statistical knowledge you throw our way, the humor is quite refreshing!😂

[@gradertfamilymakes]

I'd like to point out that the deadening is typically used for audio purposes. And not for soundproofing. That's a different product entirely. The butyl mats are to remove resonances heard typically when adding speakers that pack a punch. There is another product used to dampen back waves as well. In the audio world, this product is most often used to eliminate or reduce vibrations but also bosters or increase the measured spl by increasing the mass of the panels and therefore maintaining the pressure level. And also decreasing the volume to tune specific frequencies. All told, muscle cars guys should be using shoddy pads or Quite Barrier LD with pressure sensitive adhesive.

[@KforConstant]

The db might not have changed, but did the type of noise change? Usually the lower sound waves will come through, but the higher db are blocked. Pure db measurements won't catch this since the lower sound waves are less likely to change. REW with mic measurements would show this change

[@MatthewFinlay]

These are the unknowns… I wish we had a mic to see the frequencies it tackles better than others

[@KforConstant]

Has the sound changed? Usually the lower frequencies aren't changed much by the sound treatment. The upper more bothersome frequency is the one trying to be lowered. The db meter won't catch this. REW with a mic can show this. I compared my Mazda cx5 with a test driven Lexus rx350. They both had the same db, but Lexus sounded and felt much more isolated from the outside. This is due to the lowered high frequencies.

[@KforConstant]

Oops double posted

[@VicFroman]

Good job, stick with it. Good camera persona

[@MatthewFinlay]

Thanks buddy, we’ll slowly sound deaden every car on the fleet

[@rstar88105]

I know Mercedes will have a small amount of this matting directly behind the speakers. I remember 2000’s ML320 suvs had about a 1 square foot of matting installer right behind the door mid speakers.

[@alejandrobedolla2106]

Why not try closed cell foam to absorb sound?

[@MatthewFinlay]

That’s in my to-do list! I’m shooting video right now of it actually. I’ve only used foams to decouple mass loaded vinyl so we’ll put it to the test

[@clydeusa6596]

Don't forget heat transfer purpose.

[@MatthewFinlay]

Absolutely! Our roof sound deadening video blew my mind on how much nicer it was in the summer heat

[@Monster33336]

I'll only sound deaden the door panels and top but not the floor, instead use MLV on the floors. I can't believe it got worse, guess nothing is as simple as it seems.

[@MatthewFinlay]

Me either buddy! I’m assuming it’s just within margin of error though but damn - total waste. It’s funny you top - to you mean underside of the roof? I just did butyl and foam on the bottom side of our F150 and will be doing a video soon. While it is a difference with sound it’s nothing crazy but the heat insulation is INSANE!

[@07wrxtr1]

However - if you're doing larger/more powerful speakers - then - "arguably" the outer door skins being heavier with sound deadening behind where your new speakers will go - "should" have some benefit. - So something on the lower 3rd of the outer skin if you can get your hand in there where your speaker will go. I also think it depends obviously on how dense the metal is from the factory - thus - Older cars probably won't see a difference, but newer lighter cars utilizing aluminum might. Then add another factor - will the door speakers be running full range of frequencies vs. crossover/cutoff point so the bass goes to dedicated subs in the back? It would be interesting to see what a car stereo shop has to say on this topic.... even though it seems like few people invest thousands into stereos these days - and at best - the younger kids just "Throw" a bass box in the back to annoy people sleeping at 3am - "Dude BRO, muh bass bro!" - However - for older/mature/higher IQ individuals without unaddressed "anxiety bro" issues - some of us people like good quality sound across the entire spectrum - and therefor - will take more effort into attenuation of resonance depending upon the vehicle/situation. Most of the time it's the plastics in the door panels/clips/random things that will start to rattle.. Appreciate the video - it's one of those areas I think falls into the "it depends" - But on an older tank like that thing - not surprised there's close to zero difference. A modern Tin can on wheels vehicle would likely see a small but larger increase perhaps?

[@MatthewFinlay]

I can't thumbs this up enough! Well said buddy and I'll keep your comment up top! Sound deadening is one of those things that is extremely case by case. It's unfortunate that I completed the exterior skin second, but until others brought it up, I had not even considered it. If I had a speaker in it hands down it should be done IMO - that's a good rule of thumb regardless of perceivable noise reduction. I bet you're onto something with the thin tin can feeling - also this car just has a ton of space between things. When you cram an engine/trans and exhaust right up into the passenger compartment - I bet it'll dampen more from just proximity. The trunk test is next on my list to do and its going to be a more complicated testing. On a previous video I installed a simple Rockville powered subwoofer so we can do some testing with tones AND quieting the car. I'm going to do the first round of testing doing the trunk pan and quarter panels and then the back/underside of the trunk lid. My hypothesis is that is will be quieter but when playing test tones thru the subwoofer we will actually get a "louder" decibel reading from the speakers up front. That's my theory anyway - we'll see how it works out haha. And thank you buddy, glad you enjoyed the video!

[@07wrxtr1]

@@MatthewFinlay Yeah you should a subwoofer test with the engine idling - this way it's really about sound isolation/ambient noise. I wanted an aftermarket exhaust - albeit - a mature sounding one with an 18" resonator - for a balance of good exhausts sound but not the whole "straight pipe it bruh" obnoxiousness. First cold start with the new exhaust = "okay - the back trunk area is def getting some sound treatment!!!" - I did 1 layers of the cheap amazon wanna be dynomat and some 1 layer of "hush mat" along with some foam between the shock tower covers and rear wheel wells. Night/day difference in sound isolation and knocking down tones that interfere with the enjoyment of cruising in a high gear/lower rpm. What's funny - go drive any modern day Camry - those things are nearly silent if the bushings/shocks are not old/shot. Leather sofa on wheels - will put ya to sleep!! or any lexus model. I think from the factory they actually tune out certain resonant frequencies, then do sound dampening and isolation on top of it. Otherwise - for other situations - Tire choice can have a huge impact on road noise - then it becomes a compromise of performance tire traction noise vs. comfortable all seasons.... Rabbit hole!! This is why people that have endless income will just run out and lease a heavy expensive money pit like a MB product or Audi....lease for 36 months then RUN AWAY once the maint costs come for ya!!!

[@geronimomadmartin3499]

Have you ever tried lizard skin?

[@MatthewFinlay]

Yes! I haven’t used it in several years though. Look up making DIY lizard skin - it’s basically just paint with super small glass balls suspended in it. So small that it basically looks like a foggy clear dust. I’ve made some with buying the spheres off aliexpress and a cheap enamel paint, the actual product and another product they make called “sludge”. I’ve never been too impressed with it of my creation unfortunately - especially the sludge. We wanted to use sludge it in our shop as alternative to using seam sealer (interior only) when sealing cavities/trunk separation, etc - but it shrinks so much it couldn’t be applied except very thin or else it cracks and fails. I wasn’t impressed with paint hardness of the regular product either. It dries to a very nice looking velvet black - kinda an eggshell sheen but scratched super easy. Like think flat black cheap spray can level. Just all around wasn’t impressed

[@geronimomadmartin3499]

@@MatthewFinlay I wonder if elastomeric exterior grade paint would make a better base. It's used on stucco buildings because if the stucco cracks the paint stretches and isn't supposed to separate which conceals the crack and helps prevent water penetration.

[@MatthewFinlay]

You might just be on to something! We thought about mixing it with some of the DIY line-X/rhino line products. On the nice restorations I’ve done I’ve just switched to spraying a two part bedliner on the bottom of the entire body pan and inside floor/trunk. Game changing

[@vladyslavmorningstar]

Didn't know kilmat is russian, glad to hear it's no longer available

[@prebenjaeger]

Enjoying your shrinking country, ukro?

[@juqual78]

wink nod sure no longer available. Shell corporation cough. Skirting regulations not hard if you try 😂