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Discussion Starter · #1 ·
I've got a 2021 Tesla Model Y, and it has a serious "body boom" road noise rumble problem. Here is a brief video showing my decibel meter set to dBC (in order to accurately capture the low frequency noise level) while I drive just 20 MPH on a somewhat bumpy neighborhood road. The meter averages in the high 90's and goes as high as 105dB at one point! Yikes!


The boomy bass-y road noise is super-low frequency, centering between 35Hz and 40Hz. And it's loud and irritating, and making me nuts. It's like I'm driving inside a sub woofer! The whole car just resonates with this loud rumble on anything but the smoothest of road surfaces.

At this point I'm trying to decide if it's worth trying to tackle the problem with sound deadening treatment since the car basically has zero soundproofing from the factory, or if it is a huge waste of time. This seemed to be a great place to ask! If I could achieve even 6dB or 9dB of improvement I think it'd be worthwhile, but I don't know that it's possible.

Do folks think that a meaningful improvement could be achieved with the standard methods of dampening the metal (dynamat, damplifier, etc), then closed-cell foam, then sheets of MLV? Or is this a huge waste of time since the problem frequencies are so low and just can't be tamed?

Thanks for any thoughts!!
 

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I was going to write to identify the SPL meter, so you are doing well so far by measuring it.

iPads do not have great bass response, so it is hard to tell.

  • Does it sound loud?
  • Or is that meter bouncing around?
  • Was it dB(A) or dB(C)?
 

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Oooof, that's a hard one to address with a DIY solution. First you would need to identify the panel(s) or structure which are vibrating at the 30-40 hz. Then apply a CLD product. However, you might get unlucky and find that the resonant panel is a window or glass roof.

Alternatively, you could figure out the source or signal path and address that way. This isn't something anyone could reasonably DIY. Shame the NVH guys are Tesla would let a car ship with this issue.

edit: you wouldn't happen to be running non stock tires? Could be the tread pass frequency if you swapped to something a little more aggressive...
 

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I remember this one guy added a bunch of deadener to his car and shifted a panel resonance to a frequency that was excited while driving at particular speeds. Basically undid the work of NVH test and simulation team at the OEM. Kinda funny but super unlucky.
 

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I would start off with treating the wheel wells with mlv since I know that they’re always a trouble spots , if that doesn’t help then you’ll have to drive around while someone is listening for the trouble spots which will be kinda hard because surface panels would rattle and squeak while big flat panels like the roof, floor or doors would produce those frequencies
 

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Have you talked to Tesla? I see it a '21 so you must have recently bought it. Any road noise in the 90s should be deemed unsellable. It could be considered borderline illegal, subjecting you to over 85dB excessively (even tho it's the low end, you can still argue it to them). Get Tesla's opinion on the noise. Maybe it's something they screwed up in manufacturing. Test drive another Tesla and take your sound meter, if you have to.
 

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Discussion Starter · #7 ·
Thank you to everyone for your thoughts! To answer a few questions:

This car is 100% stock, and I intentionally chose the smaller regular wheels in the hopes of reducing road noise. They come with “ContiSilent” tires that supposedly reduce road noise by 9dB! (Hah! Yeah right)

Good observation that the dB meter is just sitting in the cup holder without any bracing. However I’ve redone the experiment with the dB meter wrapped in a microfiber cloth to decouple it from the vehicle, as well as just holding it, and the numbers are the same.

I agree that NVH really screwed up royally here. But apparently they aren’t unique. I don’t have personal experience with other vehicles, but thru my investigation of the issue I’ve been told that the Audi e-tron and Mercedes EQC suffer from the same “body boom” bass rumble road noise issues. I’ve test driven a mustang Mach e and it is similar but much less. So potentially there is something fundamental about AWD EVs in an SUV configuration that leads to this. For comparison apparently the sedan-style Tesla model 3 does not suffer from this.

I just took the car in for service to repair all the defects from factory and shipping (Tesla is notorious for shoddy build quality needing repair after delivery) and to inform them of the rumble issue. A mechanic did a 15-minute ride along with me and my trusty SPL meter where it frequently hit 100 dBC and he said basically “that’s how these cars are, this is no different from any other”.

So I’m on my own here to address this. It seems like the odds of improvement aren’t great, huh?
 

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I just want to state that a gas lawn mower is near 90 dB so I have a hard time believing driving down a normal road (with all windows closed) is as loud as a lawn mower inside. Here is a CDC hearing loss table that shows if that truly is the case, then you’d have some hearing loss in a matter of hours.


I’d really suggest getting a SPL calibrator and using your computer with a microphone to determine the loudness and frequency. I know you said near 40 Hz but how are you identifying that? And I’m assuming you’re using C-weighting as that focuses more on low frequencies while A-weighting focuses more on the middle frequencies. A-weighting is what OSHA uses to identify harmful noise levels for workers. So it would be interesting to see results for both weighting with similar conditions.

I’m not saying I don’t believe you but I’m having a hard time believing it is at the levels you mention. And at least for me, it is hard to move on to the remediation stage if we’re working with levels this high. Because even if you do a great job, you’re only looking at 4, maybe 6 dB of improvement, which still has the sound level firmly in the long-term hearing loss range.

EDIT - And I’m jealous of you as I want to get a Model 3 or Y Performance but still holding on to my car a little longer as my kids graduate high school this year. But your results definitely have me leaning towards the 3 and I was already leaning that way. Only reason for the Y would be hatchback (better bass) and seat height (ease of entry/exit).
 

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I just want to state that a gas lawn mower is near 90 dB so I have a hard time believing driving down a normal road (with all windows closed) is as loud as a lawn mower inside. Here is a CDC hearing loss table that shows if that truly is the case, then you’d have some hearing loss in a matter of hours.


I’d really suggest getting a SPL calibrator and using your computer with a microphone to determine the loudness and frequency. I know you said near 40 Hz but how are you identifying that? And I’m assuming you’re using C-weighting as that focuses more on low frequencies while A-weighting focuses more on the middle frequencies. A-weighting is what OSHA uses to identify harmful noise levels for workers. So it would be interesting to see results for both weighting with similar conditions.

I’m not saying I don’t believe you but I’m having a hard time believing it is at the levels you mention. And at least for me, it is hard to move on to the remediation stage if we’re working with levels this high. Because even if you do a great job, you’re only looking at 4, maybe 6 dB of improvement, which still has the sound level firmly in the long-term hearing loss range.

EDIT - And I’m jealous of you as I want to get a Model 3 or Y Performance but still holding on to my car a little longer as my kids graduate high school this year. But your results definitely have me leaning towards the 3 and I was already leaning that way. Only reason for the Y would be hatchback (better bass) and seat height (ease of entry/exit).
His measurements may not be 100% accurate but if he's describing booming than I wouldn't be surprised if that 90+ dB (thanks cabin gain). He would have to remeasure with the dBA setting on the meter but since this is mostly a low frequency noise issue the overall level will be reduced significantly. For example, A weighting at 40hz would reduce the level about 30 dB vs dBC.

If OP had this issue at highway speed that would be a huge issue but he will likely just have to deal with it at the specific speeds this occurs.
 

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Discussion Starter · #11 ·
Indeed these are accurate dBC measurements, not dBA. As indicated by the previous poster, the numbers are dramatically lower on the dBA scale. The same meter measuring the same events in dBA shows numbers in the mid-to-high 60's.

This is very much a low-frequency problem, as indicated by an FFT analysis of the noise. It centers between 35Hz and 40Hz. It's so low that it is more "felt" than "heard," although it is most certainly audible! It's because the noise is so heavily biased towards the low end of the frequency spectrum that there is such a dramatic difference between the dBA numbers and dBC numbers. It really feels like riding inside a bass drum.

To the commenter mentioning posting in a Tesla forum regarding this concern, there were 18 pages of comments on this issue before I came along (including several people suffering ear aches, tinnitus, and ultimately getting rid of the car because of it):

Ear pain/Pressure help

Wish I had found this before bothering to buy the car!! On my brief test drive I was so wowed by the new high-tech EV experience and trying to figure out one-pedal driving that I didn't pay too much attention to the rumble, although I did notice it.

In any event, here it is. Now I still need to decide if it's worth any effort to try to tackle it, or if I should just sell the car as several others have done before me.
 

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Well my leaf blower says 89dB, and in the small print it says at 50 feet.

My truck is in that range, but dB(C) is a bit different than dB(A)...
 

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You could always drive down the road with your UMIK microphone and REW and measure the actual response. That would be pretty accurate, lol.
 

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You could always drive down the road with your UMIK microphone and REW and measure the actual response. That would be pretty accurate, lol.
It still needs a SPL calibrator as you‘ll know the frequency but not necessarily an accurate SPL scale.

As a matter of fact OP, PM me and I’ll let you borrow an SPL calibrator since I have an extra one as I’d really like to see an accurate set of measurements on this issue. And thanks for the link to the Tesla forum. This may have saved me a lot of money from making a similar mistake.
 

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I got my Model 3 Performance just over a month ago (stupid fast, just like you think it is!) but already a decent amount of deadener to go in. Like someone else noted above, the wheel wells seem to be where the most of the noise comes in the cabin and the place to start first. My '21 even has some pieces of deadener peeking out from under the wheel well liners, letting me know that Tesla is at least following the lead of some of the aftermarket/end users trying to quiet down a "noisy" car. FWIW, I haven't gotten out my UMIK to see where the sounds land in my car but will probably do a before and after once it comes time to deaden the car.
 

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Discussion Starter · #16 ·
I got an SPL calibrator to check my dB meter and it was hot by 0.7dB, so pretty darn good. Basically my numbers are pretty much accurate. It really is a boomy vehicle.

So does anyone think that this is a resolvable problem? Or is this just too big of a mountain to climb?
 

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I mean you could gut the car, apply deadener, and get lucky.. No good way for a DIYer to really diagnosis this issue.

If you haven't already, maybe someone on a forum somewhere has already deadened the crap out of their model Y and they could share their results with you..
 

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I got an SPL calibrator to check my dB meter and it was hot by 0.7dB, so pretty darn good. Basically my numbers are pretty much accurate. It really is a boomy vehicle.

So does anyone think that this is a resolvable problem? Or is this just too big of a mountain to climb?
The short answer is this can’t be fixed, not to an appreciable degree.

I’d still like to see numbers with A-weighting as more of a level set but that is secondary to the deep bass issue at hand.

But you’re really saying the Model Y is a drum that you’re inside of. This isn’t external noise you’re trying to block. This isn’t panel vibration on a small scale that you can address.

The steps to address would be to pull the interior out, put down some CLD, which is really more for panel vibration attenuation, then put down a sound barrier such as MLV, and then isolate with CCF. But I doubt that would do much for the frequencies and loudness you’re describing. You could probably make a good first pass on the doors and wheel wells but for the boominess, there really isn’t anything we could prescribe for that as we‘re not sure of the source.

And that really sucks!
 

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it is cheaper to try to solve that with deadening/sound barieres than selling the car and buying new one,....which will still need to be sound treated. This low freq noise is hard to block, but there will definitelly be some more positive outcome.
 
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