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Briggiboy33

Windows down volume increase

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Sprint so I have a 06 tundra access cab with a fi x12 in I believe 2 cuft ported box tuned to around 32-34 maybe. But why do I notice such a big increase in "volume" of the sub when I put the windows down or open a door? This is probably a noob question but I'm just curious. Thanks. Btw it's running on a 400rms powerbass amp. It's where the back left seat would be. Standing up with the sub facing drivers seat and port facing the passengers side. Thanks

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Sprint so I have a 06 tundra access cab with a fi x12 in I believe 2 cuft ported box tuned to around 32-34 maybe. But why do I notice such a big increase in "volume" of the sub when I put the windows down or open a door? This is probably a noob question but I'm just curious. Thanks. Btw it's running on a 400rms powerbass amp. It's where the back left seat would be. Standing up with the sub facing drivers seat and port facing the passengers side. Thanks

thats supposed to say alright. not sprint...

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I dont know exactly why.. But it seems to happen to a lot of cars. If you open the passanger door or window it will sound louder. Just the way it is? :D

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The vehicle acts acts as an enclosure, when the window / door are open, it effects the characteristics of the "enclosure." Something like that. :shrug:

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Its like having a ported enclosure in a sealed enclosure, its harder for the sub to move air that just fills the cabin compared to the air being easier to move through an open area like a ported enclosure. Its all about the amount of air available to move and how easily the sub can move it.

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If you can see your subs...watch them. They probably move a lot more with the window down. More travel = more sound.

On a side note, I can change my frequency response completely just by rolling windows down. My box is tuned to 28hz and with the back windows all the way up I can play into teens (about 17hz) with no problems, but it's only good for rap music lol. When I want to listen to something more complicated or snappy (Like double drums in rock) I roll the back windows down and get a nice boost in the 40~60hz area. Just mess with it and see how it changes the sound and you might find something useful.

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If you can see your subs...watch them. They probably move a lot more with the window down. More travel = more sound.

On a side note, I can change my frequency response completely just by rolling windows down. My box is tuned to 28hz and with the back windows all the way up I can play into teens (about 17hz) with no problems, but it's only good for rap music lol. When I want to listen to something more complicated or snappy (Like double drums in rock) I roll the back windows down and get a nice boost in the 40~60hz area. Just mess with it and see how it changes the sound and you might find something useful.

I'm skeptical of that.

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I know my Explorer Sport sounds louder with the windows up, And my 94 limited I use to run was louder on the lows sealed up. But my Focus was louder all the way around with the windows down. Just up to the acoustics of the vehilce I guess.

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Its like having a ported enclosure in a sealed enclosure, its harder for the sub to move air that just fills the cabin compared to the air being easier to move through an open area like a ported enclosure. Its all about the amount of air available to move and how easily the sub can move it.

X2

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all cars are different .. and all seats will sound different..

in the driver seat you may notice a gain.. but in the passenger seat you may notice a drop in pressure.

in my car.. the driver seat with the doors closed and the two front windows down in loudest BUT. if you are in the passenger seat, doors closer driver window down and passenger window up is loudest.

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If you can see your subs...watch them. They probably move a lot more with the window down. More travel = more sound.

On a side note, I can change my frequency response completely just by rolling windows down. My box is tuned to 28hz and with the back windows all the way up I can play into teens (about 17hz) with no problems, but it's only good for rap music lol. When I want to listen to something more complicated or snappy (Like double drums in rock) I roll the back windows down and get a nice boost in the 40~60hz area. Just mess with it and see how it changes the sound and you might find something useful.

I'm skeptical of that.

Mine do. Considerably. Play your subs with the trunk/hatch open where there's less pressure and see. It may be harder to see at first with just the windows down but if you do it with the trunk or doors you'll see.

EDIT: Now that I think about it, just remove the area that the subs load off of and they'll move more. If you have a loading wall, for example, it wouldn't make a difference. My subs load off of my roof, so when I roll the windows down or open the hatch it gives the subs a bigger "car" to pressurize.

Edited by An-i-no

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all cars are different .. and all seats will sound different..

in the driver seat you may notice a gain.. but in the passenger seat you may notice a drop in pressure.

in my car.. the driver seat with the doors closed and the two front windows down in loudest BUT. if you are in the passenger seat, doors closer driver window down and passenger window up is loudest.

Thats how my SUV is, whenever I just cruise around with the windows down, my seat is louder, but when I demo'd my old 15s I had, I'd roll up the passenger window making that side of the truck "louder". It's always good to figure out our vehicles acoustics.

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Nope...particle velocity schmarticle velcoity. Your ears aren't being fooled, they're hearing more bass at and around a particular frequency--the frequency where the car is tuned with the open window.

The particle velocity is increased at the window when there's no window. Pressure is high at a boundary and velocity is low. Eliminate the boundary and the velocity is increased...no mystery. Since the open window becomes a radiator (port) you'll measure greater velocity at the window than in the center of the car.

When you put a box in a car, the domain, or the listening area, is also a sealed box. That's where cabin gain comes from. When you roll down the window, the sealed box in which you listen becomes a vented box. The pressure inside a vented box is quite a bit greater than in a sealed box of the same volume at the same frequency.

It's easy to measure if you have a high-resolution analyzer. Geez, you can even measure it with a 1/3rd octave RTA, but you'll have a more difficult time seeing it.

One thing Richard is right about is that the overall level isn't necessarily higher, but the level at the frequency where the open window tunes the box is louder.

I've had people ask me this question hundreds of times and i've heard hundreds of explanations.

The pressure increases in the car at Fb (now Fcar). Rolling down the window creates a port, which tunes the car to some frequency. That frequency is where the pressure increases (and at adjacent frequencies too).

If you have an RTA and a vented box, drill a little hole in it and insert your microphone. Measure the frequency response. Then, seal the box by screwing a piece of wood over the port and measure again...More pressure at Fb. You'll also notice, if you use a sine wave sweep, that the woofer's excursion at Fb is at a minimum.

-Andy Wehmeyer

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Like the others have said, your car acts as an enclosure. Almost like a bandpass. You will probably notice that its more the lower notes that get louder while the 45+ hz may not. (At least for me anyway)

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He lows hit way harder with the windows down. With the windows down it's just louder all around. But very much so with the windows down. But I want to say iv read something about he port size has something to do with it or thee box size.... Not sure

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Everything in the vehicle plays a roll.

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I notice in my vehicle with my enclosure in the truck that with my front wondows down it helps out the lows kills the high hz and does get louder. But if i put my back windows down my low lows get considerably louder, while i lose response 45 hz and up.

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The vehicle acts acts as an enclosure, when the window / door are open, it effects the characteristics of the "enclosure." Something like that. :shrug:

The vehicle acts like a 6th order bandpass.

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For me all windows down gets loud as hell and rolling up rear driver side with rest down makes the lows insane.

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In my Taurus, windows down made it sound twice as loud, but not in my escape windows/doors do nothing to change the sound.

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Also opening doors or windows Makes your car flex more.. Its funny how sometimes on youtube say "Look how much flex!!! And thats with all the windows/doors open!!"

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I use to notice this a lot in my smaller, 2-Door Olds Alero. Roll down the windows and wham, it'd get louder.

I'm not noticing it as much now in a larger, 4-Door Chev Impala ... it's probably still there though.

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The vehicle acts acts as an enclosure, when the window / door are open, it effects the characteristics of the "enclosure." Something like that. :shrug:

The vehicle acts like a 6th order bandpass.

exactly, Increasing port area can sometimes overcome that effect...

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I notice in my vehicle with my enclosure in the truck that with my front wondows down it helps out the lows kills the high hz and does get louder. But if i put my back windows down my low lows get considerably louder, while i lose response 45 hz and up.

Also keep in mind with higher tones that usually opening up a window or door up front will hurt your midbass drivers since they are IB, and you are kinda taking that away. that's why your upper bass frequencies, probably closer to 60 and up go down. lots of rap is around 40 hz,...

Also opening doors or windows Makes your car flex more.. Its funny how sometimes on youtube say "Look how much flex!!! And thats with all the windows/doors open!!"

It depends on the strength of the system, on huge systems that's definitely not true as big systems have the ability to push on anything in a car including the windshield to try and push the air inside the vehicle out.

On smaller systems that may be true because they simply aren't that loud to begin with, so need every bit of help just to make some noise and get something to "move" a little.

To the OP: Definitely depends on vehicle, like everyone is saying, but the reason has to do with how much air your system is capable of moving. for example, SPL driven vehicles built for a "burp" is usually at higher frequencies where the woofers aren't moving much so the better the vehicle is sealed the louder the db's as the woofers have tons of motor force to pressurize the cabin.

Whoever made the comment about woofers moving more, is also right, if you relieve pressure placed on an object that is moving, you are enabling that object to move more....that's just plain physics.

Trucks: OP, you have a truck, I do too, and when the enlosure is in the cabin, the woofers are loading inside the cabin, so when you open your windows or doors (more the better) then you are giving your system more air to move and enabling them to move further. In a truck it will a much more dramatic change as opposed to a trunk system or cargo area SUV system where the woofers are loading in the rear of the vehicle and pushing air to the front. It's simply wherever the air has to move... but every truck, I mean every truck will be louder with windows/doors open.

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