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<blockquote data-quote="Immacomputer" data-source="post: 4880557" data-attributes="member: 570419">100% agreed. My sunroof open allows no air in while driving no matter what speed unless another window is open (or if I have it cranked)It&#039;s doubtful that it acts like a ported enclosure; do the math and you will find that the tunings aren&#039;t very consistent with the theoretical calculation given the area and depth of the sunroof. I think when I did the math on my car, with the sunroof open it should be tuned to about 40hz or something high like that but I&#039;m getting resonance (high amounts of air movement) from 20-30hz. I think it acts more like a mass loaded transmission line does. The cabin of a vehicle is very much like a transmission line enclosure and mass loading the open end of a transmission line by obstructing its mouth with a small port will yield low resonance points and more consistent velocities of air around the two resonance points (line and air mass). I could be way off&nbsp; but it makes more logical sense to me than the ported idea.</blockquote>

[QUOTE="Immacomputer, post: 4880557, member: 570419"] 100% agreed. My sunroof open allows no air in while driving no matter what speed unless another window is open (or if I have it cranked) It's doubtful that it acts like a ported enclosure; do the math and you will find that the tunings aren't very consistent with the theoretical calculation given the area and depth of the sunroof. I think when I did the math on my car, with the sunroof open it should be tuned to about 40hz or something high like that but I'm getting resonance (high amounts of air movement) from 20-30hz. I think it acts more like a mass loaded transmission line does. The cabin of a vehicle is very much like a transmission line enclosure and mass loading the open end of a transmission line by obstructing its mouth with a small port will yield low resonance points and more consistent velocities of air around the two resonance points (line and air mass). I could be way off but it makes more logical sense to me than the ported idea. [/QUOTE]

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