[zach no sauce]

The resonance is with the windows closed.
Here’s a video - hope that the encoding doesn’t lose the low frequency range, hope you have good earbuds or stereo to hear it.

if not, the iCloud link is below...

resonating at 40MPH

 

[zach no sauce]

Agreed my phone is probably mismeasuring. Nonetheless, it’s not at all quiet. It’s loud. I get that I can go to DIY sound-deadening work, and perhaps I will eventually.

But focusing on the very low frequency resonance/reverberation, that one may just drive me mad. Nobody else is experiencing this sound pressure near the inaudible point in the spectrum?

 

[zach no sauce]

Starting to wonder if you guys just don’t hear low frequencies!
The dealer service manager said “yeah, it’s a thing, no fix."
Went to another dealer today, sat in another one and it has the same resonance characteristics sitting still. the uppper half of this thing is extremely prone to vibration, at least Limiteds or higher with the large moonroof are. “Normal."

I have the standard Yokohama Avid 17”s on it. I saw someone else complaining that these were hard tires. They were also on our 2017 Pac gas, seemed fine there…. yes, new better tires may help with keeping the resonating characteristic from happening as often, but clearly the frame should not resonate like it does. It’s not underpanels guys. I thought it was at first. It’s not. Its also been on a rack and cleared of anything suspect going on underneath.

 

[zach no sauce]

Factory tires are crap.

Okay. In what way have you found them crappy. What tires have you landed on being awesome?

 

[zach no sauce]

I don't hear anything resembling a loose panel like you describe in the video. I'm not trying to be mean, but the truth is that you talking the whole time makes it hard to discern much of anything. The loud sound I do hear doesn't correspond with what I see in the picture of your phone's spectrum analyzer at all. The loudest frequencies I'm hearing are far lower. The spectrum analyzer on my computer shows a large spike at around 38Hz at various places in the video, but is most prominent around the 10-14 second mark. I agree with your assessment that a loose baffle or panel isn't going to cause this. Sound recordings in cars tend to sound artificially boomy anyways, but even considering that yours seems louder than normal. What's also not helping is that the resonant frequency of the cabin is probably somewhere around 35Hz-40Hz which will make that sound seem louder than it really is.

The active noise cancelling might be malfunctioning. You can try pulling the fuse for the stereo amp (F08) and going for a drive to see if the sound persists with ANC disabled. If the boomy sounds go away then there's clearly an issue with the active noise cancelling. If not, then you may be dealing with road noise for which there is no solution just like the service manager stated. You could install sound deadening, but I don't think it would do much to dampen frequencies that low.

Thanks for your notes here. Yeah as I think about it, it can’t be as high as the analyzer shows it to be. More like 50hz if I was to guess just hearing it. So 30-45 makes sense and lines up with why it’s not audible on phones or most computers.
i can and should try the ANC disable but I’m guessing it won’t be different because just closing the drivers door a boom sound is heard that sounds similar for a much longer period then I would expect. We did reproduce it with another Pacifica with a sunroof yesterday. But I drove a voyager and it had much less boom on door close and much less driving as well. Perhaps it is consequence of the moonroof