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  • juniormarbles ·
    .... continued:

    The wedge-shaped open space (looking at it from the side of the car), starting behind the driver and ending at its smallest volume at the rear bumper, generates standing waves and a very low frequency resonance, with the wedge's orientation (largest open space closest to driver) boosting low frequency volume at the ear position of the driver (megaphone effect). I could duplicate the low frequency thump by knocking against the rear window with my fist. The moment I open the rear lid, even by just a few inches, it disappears (because the space's dimensions are thus altered).

    Your approach of mitigating the muffler drone at its source makes therefore much sense. This will unfortunately not help the road noise/tire drone.

    Best,
    JM
    juniormarbles ·
    I would be extremely grateful if you could give me a hint (or point me to a thread) about how to remove the Cayman trunk carpet (rear end of trunk area) so that I can install Dynamat panels in the lower thin-metal trough.

    I truly enjoyed your extensive thread on exhaust drone. I am an acoustician by profession and can add this much to the discussion: the low frequency (below 100 Hz) road drone I get from transmission via drive train into the cab will most likely remain:

    (continued on second PM, due to character limitations to 1000)
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