bass hits harder with my trunk open! WHY???

[matt6288]

im having a hard time bringing myself spray foam anything in my new car this is my only family car so I will do m y best and yes I will be building a new box to cover up that whole front area around the seats to get the best seal I can without tearing into it. (we'll see I might just cant take it and do it anyway) The Five hundred is a great car REAL ROOMY that's for sure great with the family. when looking for one get one with the bigger motor I got a not so powerful motor. but all in all its a great looking car you can make them look really nice just got the windows tinted it comes with factory 18" wheels looking for some chrome 20"s tho. all black leather moon roof fully loaded, I would definitely recommend it. oh yeah and plenty of trunk space for speakers and other stuff

yea i agree with just building a new box that totally fills that space get you some expand foam and that second skin. and seal it up . it will be alot louder and cleaner sounding. btw, how is the five hundred? im thinking about getting one in the next month or so...

[iCool247]

My 8s hit harder when the passenger's door is open

[matt6288]

WONDER IF IT IS THE SAME THOERY IN EFFECT WITH YOU DOOR AS WITH MY TRUNK

My 8s hit harder when the passenger's door is open

[IH8PunkRok]

I forgot the exact theory. Might be the vortex theory. IH8PunkRok had 6 8's sealed off firing forward in his mustang and was like a db louder with his trunk open. It was crazy when one our teammates who has more been competing for a long time told us to try it. But it worked.

no way he was sealed then

its physics.

seal off your trunk op

i was sealed off but there was an airleak i was not aware of until later. ill explain why it gained in response to meades post

the reason it does that is because it is cancelling out (when your trunk is shut). Bass is firing forward, then some of it is leaking backward through your leaky rear deck and the openings around the box itself. It travels backwards, hits the back of the car and then comes forward again but now its playing bass 180deg out of phase..basically reverse (to make it easier to explain). When you play a sound, and the same sound exactly the opposite, you get cancellation and the bass is reduced. Sorta like hooking up two subwoofers up out of phase, you know what i'm talking about? Anyway, When you open the trunk, the leaky bass is going backwards, and out of the car instead of bouncing back into the cabin.

This is why a car with a box aimed backwards typically sounds better then aimed forward (non properly anyway). Because the bass rolls off of the woofer and goes directly into the cabin, you get no cancellation. For a forward firing box to work properly, it needs to be sealed off from the trunk so no bass goes backwards at all, giving it no chance to cancel out.

you are correct that the bass traveling backwards is the culprit but you are wrong about it cancelling out. it doesnt exactly work like that in the lower frequencies.

you see bass doesnt really act so much like a wave. its more pressure based rather than wave based.

the reason OP and my trunks got louder when the trunk was open was due to the vortex theory. to keep it simple there was more air available to be pressurized. since the boxes are not 100% sealed off the air in the back of the trunk was being pressurized but not really aiding in adding pressure. sort of like water sloshing around in a container. it moves back and forth but there are stagnant pressure zones where the air gets "caught" and swirls instead of moving in the direction it was intended

now when the trunk was opened the entire trunk became a low pressure zone. all the air outside is your high pressure zone. bass plays and the air comes rushing in. more air more pressure more loud

i could write pages and pages on this subject but i wont because no one will read it. but id just like to leave you with this thought. ever wonder why terry brocks (the loudest trunk car in the world) never has his subs at the front of the trunk and sealed off?

[Brandon15zzz]

^^^Winning.

[DubNDodge]

Really interesting....

Any links to Terry Brocks trunk build?

[meade916]

I forgot the exact theory. Might be the vortex theory. IH8PunkRok had 6 8's sealed off firing forward in his mustang and was like a db louder with his trunk open. It was crazy when one our teammates who has more been competing for a long time told us to try it. But it worked.

no way he was sealed then

its physics.

seal off your trunk op

i was sealed off but there was an airleak i was not aware of until later. ill explain why it gained in response to meades post

>the reason it does that is because it is cancelling out (when your trunk is shut). Bass is firing forward, then some of it is leaking backward through your leaky rear deck and the openings around the box itself. It travels backwards, hits the back of the car and then comes forward again but now its playing bass 180deg out of phase..basically reverse (to make it easier to explain). When you play a sound, and the same sound exactly the opposite, you get cancellation and the bass is reduced. Sorta like hooking up two subwoofers up out of phase, you know what i'm talking about? Anyway, When you open the trunk, the leaky bass is going backwards, and out of the car instead of bouncing back into the cabin.

This is why a car with a box aimed backwards typically sounds better then aimed forward (non properly anyway). Because the bass rolls off of the woofer and goes directly into the cabin, you get no cancellation. For a forward firing box to work properly, it needs to be sealed off from the trunk so no bass goes backwards at all, giving it no chance to cancel out.

you are correct that the bass traveling backwards is the culprit but you are wrong about it cancelling out. it doesnt exactly work like that in the lower frequencies.

you see bass doesnt really act so much like a wave. its more pressure based rather than wave based.

the reason OP and my trunks got louder when the trunk was open was due to the vortex theory. to keep it simple there was more air available to be pressurized. since the boxes are not 100% sealed off the air in the back of the trunk was being pressurized but not really aiding in adding pressure. sort of like water sloshing around in a container. it moves back and forth but there are stagnant pressure zones where the air gets "caught" and swirls instead of moving in the direction it was intended

now when the trunk was opened the entire trunk became a low pressure zone. all the air outside is your high pressure zone. bass plays and the air comes rushing in. more air more pressure more loud

i could write pages and pages on this subject but i wont because no one will read it. but id just like to leave you with this thought. ever wonder why terry brocks (the loudest trunk car in the world) never has his subs at the front of the trunk and sealed off?

ummmm, sorry bro, but i will stick with my answer.

[STEvil]

Nothing to do with vortex theory, its just wave propagation physics. Same reason a t-line or horn sounds best further away.

[Brandon15zzz]

....it was still louder though

[IH8PunkRok]

Nothing to do with vortex theory, its just wave propagation physics. Same reason a t-line or horn sounds best further away.

explain it. just out of my own curiousity