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Message: <blockquote data-quote="VWBobby" data-source="post: 7566227" data-attributes="member: 624844">Fi-brations, (cool name BTW //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif)My BMW is all stock.  Its an '02 330xi with every option from the factory.   It has the 12 speaker Harman-Kardon option that is basically a 3-way active stage, rear speakers LPF'd at about 3000hz, and back speakers LPF'd at about 100hz from what I can tell (sounds like subwoofers).   If you hit a button in the dash that looks like a speaker, it turns the rear speakers into full-range mode so the people in the back seat can hear better.  It also makes it sound like 5.1 channel surround but definitely kills the front stage presence. :-/If I was to rate it, I would say an 7 - 8 out of 10, for all the systems I've heard.  Definitely the best stock stereo I've ever heard.I did take the driver's door panel off to replace the lock mechanism and found a moderate amount of deadening behind the panel and in the door.  There are a few holes that could be sealed up, but nowhere near as many holes as most cars I've seen.To seal the holes, you can simply cover them with sound deadener up to about 4".   Large holes will need a blocking plate made out of plastic or plywood.  MDF will soak up water and turn to mold unless you fiberglass it in.  Seal the plate to the car with some screws and autobody sealant.  Otherwise you can use automotive adhesive, but it will be a pain trying to get the plate back off.By "too much deadener" I mean the people that have 2 layers of regular deadener, a layer of closed cell foam and finally a door panel.  When you stack up all that deadener, it turns your door panel from being a speaker baffle/box into a dead chamber.   Its like playing a speaker in a padded/muffled box compared to having some hard surfaces in the cabin.  Similar to how drummers stuff a pillow in their kickdrum to deaden and muffle/deepen the sound. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gifThe key to a properly deadened vehicle is stopping panel vibrations and adding mass to resonant panels.  If you have door panels rattling, that not only contributes to noise but creates a loss of energy since the speaker is vibrating in its baffle.   The panel needs to be stiff.  Some people say you want to "decouple" the panel from the door by isolating it from the door with deadener.  I don't agree.  In my testing, having a door panel made of wood and fiberglass rigidily mounted to the door sounds a hell of a lot better than the typical plastic and vinyl/cloth covered door panels found in OEM.  To me, its the equivalent of a very large solid enclosure and gives the speakers the best environment to perform.Deadening the floor, walls and roof is good for decreasing your cabin noise which gives the perception that your stereo is playing louder, since you don't have to crank it up to overcome the noise.If you simply seal up your doors and run 1 layer of deadener on all panels, maybe 2 layers on the floor and wheel wells since these make the most noise.....you will have one fine environment for whatever speakers you choose. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif  BMW designs and builds their cars to be quiet from the factory, so they don't need a lot of help.   They are notorious for "******* power" in subwoofer installations because the trunk and cabin is already heavily sound deadened.  You find a lot of owners having to run more power just to overcome the deadening. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif</blockquote>

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