thaxton Posted April 28, 2011 Report Share Posted April 28, 2011 Hey everyone, I just had a question about windows up/down. I have a 2001 grand marquis with 2 15's sub/port to the rear. When in the front seat, the bass is loudest with the windows down. I generally understand that the window acts like a port, and I can feel the "pressure zone" when I put my head by the window. The other day when I let my buddy drive, I was sitting in the back, I noticed that when all the windows are up, the backseat gets much more violent. It is half as loud in the front sealed up and twice as loud in the back. Why does this make the back seat so much louder. Also, the box is about 10 cubes (outside dimensions) so it takes up nearly the whole trunk. Don't know if this could be a variable or not. Anyone with some expertise in this area want to chime in? I was just wondering what the "techical" explanation of this would be. Quote Link to comment Share on other sites More sharing options...
corey0928 Posted April 28, 2011 Report Share Posted April 28, 2011 Its closer to the subs Quote Link to comment Share on other sites More sharing options...
thaxton Posted April 28, 2011 Author Report Share Posted April 28, 2011 Possibly, but with windows down, the front seat is louder than the back. Quote Link to comment Share on other sites More sharing options...
bdubii Posted April 28, 2011 Report Share Posted April 28, 2011 It sounds like your experiencing some noise cancellation in the sound waves. When your in the back seat I'm guessing that the location of your ears are in a better spot where the sound waves actually constructively interfere with each other causing a louder and more violent bass. In the front seat the difference in location can be causing the waves to be destructive interfering where they might be close to 180 degrees out of phase. And when the windows are down that can change the wavelength tremendously. Just my idea Quote My build, four 15's walled: http://www.stevemeadedesigns.com/board/topic/106855-07-tacoma-walled-off-with-4-15s/page__p__1487297#entry1487297 Link to comment Share on other sites More sharing options...
thaxton Posted April 28, 2011 Author Report Share Posted April 28, 2011 It sounds like your experiencing some noise cancellation in the sound waves. When your in the back seat I'm guessing that the location of your ears are in a better spot where the sound waves actually constructively interfere with each other causing a louder and more violent bass. In the front seat the difference in location can be causing the waves to be destructive interfering where they might be close to 180 degrees out of phase. And when the windows are down that can change the wavelength tremendously. Just my idea That actually makes a lot of sense, i didn't think about cancellation. The waves could be bouncing back and creating a "dead spot" up front when the windows are up. It is extra noticable on the lows. Also, the car itself has some funky acoustics I think (weird trunk design and pass thru to the cabin. Higher bass seems to come in the cabin along the roof, low bass seems to come up from the floor). My gf has a camry with 2 12's and it sounds about the same everywhere in the car windows up or down. Quote Link to comment Share on other sites More sharing options...
bdubii Posted April 28, 2011 Report Share Posted April 28, 2011 That would be my guess. You said the box fills up the whole trunk so I guess there is no way to play with the position of the subs and see if it makes a difference then? Quote My build, four 15's walled: http://www.stevemeadedesigns.com/board/topic/106855-07-tacoma-walled-off-with-4-15s/page__p__1487297#entry1487297 Link to comment Share on other sites More sharing options...
RLB910 Posted April 28, 2011 Report Share Posted April 28, 2011 Agreed that you are experiencing cancellation. A suggestion would be to completely seal off the trunk from the interior. When you lay the back seat down you will see the face of the box and the speakers. Have the port enter the interior through the rear deck. That way the sound will be originating from almost the same plane. Here is a little article about it. ( http://www.mobileinformationlabs.com/HowTo-1WooferBox-bass_cancel_1.htm ) Hope this helps Quote Link to comment Share on other sites More sharing options...
bdubii Posted April 28, 2011 Report Share Posted April 28, 2011 That would probably make a difference. It will be almost impossible to seal off the trunk though. There are so many small holes and passage ways in any car between the cabin and the trunk for sound to travel through. Especially lower frequency sound that can get through just about anything Quote My build, four 15's walled: http://www.stevemeadedesigns.com/board/topic/106855-07-tacoma-walled-off-with-4-15s/page__p__1487297#entry1487297 Link to comment Share on other sites More sharing options...
thaxton Posted April 28, 2011 Author Report Share Posted April 28, 2011 Sealing off the trunk would be very difficult in this car, especially with 15s. You would have to do some sort of bandpas or something. I don't know if you guys have seen a crown vic/grand marquis trunk, but there is a huge gas tank hump. the pass thru to the cabin is only like 10 inches tall, and the seats don't fold down, so I don't think firing forward is an option. It sounds decent the way it is. Cancellation seems like it makes sense for what I am experiencing. Quote Link to comment Share on other sites More sharing options...
BassJunkie Posted April 28, 2011 Report Share Posted April 28, 2011 Have you tried different sub positioning? If you can get that "violent zone" up on that dash it'll be good on the meter Quote 1986 C20 Suburban 9 American Bass XFL 15's B2 M1MKII 14v XS Power Batteries Maxwell Caps Acoustical energy is free. Electrical energy is not you havent lived until you've hit a screw with a router. Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.