Soundproof fail- any advice?

I am trying to reduce the rear road noise in my truck. I own louder cars and trucks, but there is something about the pitch in my 2020 Tacoma TRD sport which literally triggers my migraines. I spend a lot of time on the road so anything over an hour sucks. I have read most of not all of the posts re spundproofing, dynamite, and noico on this forum.

So far I have gone to the quietest reviewed tire (yoko geolander), put 80 mil second skin on the inner and outer panels of the doors , and put it on the rear wall, put 2 layers of mlv on the rear wall, put second skin under the rear storage , put a few pieces of mlv under the rear seat.

I have a stretch of interstate I test this on and interior db has gone from 70 to maybe mid 60’s. My options are to go nuclear and put a lot more foam in the doors and back wall, like noicos 315 mil . Or I can have someone do the floor and headliner but that gets expensive- I really don’t have the ability to pull the seats and do a full floor install.

any advice appreciated- do any of the above extra options? sell the truck?

thanks in advance

 

Could be a certain frequency and not just general noise? I'd be tempted to get out a mic and a spectrum analyzer app and do some poking around, maybe you can target the offending noise more precisely.

 

60dbs is pretty quiet for a truck. Headliner does make a big difference when I did it, as well as the floor. I still need to do my driver's door now that you reminded me.
I'd suspect it's a specific frequently as stated above

 

Try Rockwool in the voids behind the interior panels.

 

When I did the complete sound proofing in my truck , I measured the sound with my decibel meter before and after .
75 decibels before sound proof at highway speed
60 decibels after soundproofing at highway speed
You dont get much bang for your buck . Thats about $1000 bucks in soundproofing material and at least 24 hours of my time to install
Stereo sounds fantastic mind you

 

A 3 decibel decrease cuts the sound in half. A decrease of 10 dB decreases the noise by a factor of 10. You dropped your noise level by 15 decibels, and that's huge!

Decibel Scale - measure the different levels of sound | SoundEar Int.

 

You may need to isolate the source that is making the sound pitch.

IE. Tires can produce a steady tone at speed. The tone will shift with speed.

What are your tires?

Another source is the exhaust. Have you replaced the exhaust or have OEM?

 

Definitely add the sound-deadening to the headliner. It's not that difficult to do yourself.

 

Get the truck undercoated.

 

You need Mass Loaded Vinyl (MLV), yes it would get quite expensive and lots of effort to install but it's the unfortunate reality.

 

The headliner was the biggest payoff for me. It also kept the truck wayyyy cooler in the summer.

 

Is it wind noise that is the culprit, or road noise? Naturally my mind thinks go down and do the floor, but how does the headliner improve the sound quality? Sorry for my ignorance on the subject, just trying to understand. I never really thought my truck was that loud inside.

 

The lower 60db range is luxury car quiet.

I would definitely do the headliner and floorboards. You get more noise from those two areas than you think. The wind noise from the roof and reflected road noise from the floor. I would also look into putting some foam weather striping in the vents at the back of the cab. I did that and there was a noticeable difference. I believe it was 1x1 foam. Just be careful not to push the rubber flappers out or you run the risk of getting water inside.

 

For me the noise was due to gear on the roof rack. But the stock headliner has NOTHING in-between the sheet metal carpet stuff.

Before I put the material in I could feel heat radiate from the roof. Not anymore.

I've sound-deadened and put NOICO foam on everything except for the floor....which I'll do at some point.

All and all it's cheap and easy. Do it yourself and make sure you buy the better quality roller, not the junk one.

Be warned though.....as you add insulation you do kill noise but you'll hear other noises "better".

 

Like ripping a fart when other people are riding with you?

 

With the butyl-backed stuff and the paint-on stuff you're are only dampening the vibrations. The vibrations are the source of noise, so you've basically only completed half the job. The MLV or the thicker layer is to insulate you from sounds originating from outside the cab; those not caused by immediate vibrations.

 

Hello sir,......I am going to look at this from 2 points of view.....Mechanically and Medically (sorry, its the Dr. in me).
Mechanically - I would follow through with the deadening on the roof but if that doesn't help, I am wondering if the sound that you are hearing is a frequency that might be either electronic in nature due to rev of the engine going through the electronics....or possibly the aspect of the small slight whine the engine might produce going through its revs. If that might be the case and you are used to extremely quiet (luxury) type vehicles, maybe sound deadening on the firewall and extra rubber seals on all of the doors to completely eliminate wind noise or road noise possibly through he door.

Medically - Migraines can be debilitating and triggered through fine mynute things. Something small such as a reflection frequency of light off of the hood or a the slightest adjustment in sound pitch. I have a number of follow up questions.
1) Do you have an Aura that is a precursor to your Migraines?
2) Have you ever tried, just for shits and giggles, driving your truck for a small stretch first with than without ear plugs to see if it makes a difference. If it makes a difference and it isn't triggered through any light aspect, the only way is to get the frequency spectrum analyzed.
3) whereabouts are the migraines localized? It can make a difference....

 

Thank you for all the replies. For some reason the response notices went to spam so I didn’t see them until now.
I have isolated the problem to the low frequency range, and it seems to be mostly from the bed of the truck. I have been using an audiometer app which is accurate to tell me that my other suv and trucks are actually louder at times but don’t trigger HA. The big difference e is they are louder at higher frequencies. My cars range from a 1984 4runner, 2015 Silverado (sold to get the Tacoma), my wife’s Merc suv. Of course the Merc is quiet but I’m not going for that. My 4Runner runs mid to high 70s db but it doesn’t bother me the way the Tacoma does. The road noise is definitely the source- and I even bought the quietest rated tires already. Also, I had put down 1” rubber in the bed a while back and forgot about it, however, I recently removed it and noticed a noticeable change in noise- jumped back to near 70 db.

I had an interesting side experiment. My son bought a nutribullet which is 117db! I made a plexiglass case which brought the noise down to 95 db. Interestingly I laid 80ml secondskin and 1# mlv on it with literally no change in noise. So, I think these materials work better when thicker . I plan to redo the rear wall and doors w thicker secondskin. I’m also going to lay rockwool where I can, starting w the bed under the liner. I don’t think I’m up for doing the headliner myself but will see if a local shop is willing to just do that for me.

#crashingiggles, I appreciate the input. I am on rizatryptan, and this relieves the sx. Obviously it is better to avoid triggers, hence my ongoing effort to quiet the sound.
When I figure out how to download the audiometer images from the app, I will post them. I have a feeling one of the above improvements will get this under control.
Again all ideas welcome and I will post when I know more.

 

Thanks!that’s what I was thinking- thank you for confirming. I’m goi g. Ack the doors and laying on mlv, maybe another layer of secondskin.

 

for me it is definitely road noise, likely tires but again, I’ve gone w the supposedly quietest in testing - yoko geolanders. Will the headliner help w road noise or just wind noise? I don’t think I have the time to do, but maybe a shop would do just that for me.