I don't have experience with the Toyota Sienna in particular, but having driven many different cars, this type of vibration isn't unusual. Especially on less expensive cars, there is less care taken to test vibration from speakers and its effect on interior panels. There is some damping material you can buy, but with that, you have to remove the interior panels and wrap it around the speakers. You might also be able to pull those panels and just try to tighten the screws holding the speakers in place, but that's not a guaranteed fix. The higher end audio option might have alleviated this problem, just because there would have been more care taken in fitting the system to the car.
Hi,
I just purchased a 2009 Toyota Sienna minivan with factory-installed non-JBL audio system.
If I keep my hand on the door while the audio is playing (not in too high volume), I feel the door vibrate. As I said, this is not a high volume, high bass music. In fact, I changed the bass to '-3'.
Could you let me know if this is normal. If not, could it be a problem with the player, speakers and/or both? By the way, I find that the sound I hear is not that crisp either.
Thanks so much,

Chowhound
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