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View Full Version : Alot louder with door open, not enough port area?



JoshC
06-26-2012, 10:08 PM
So ive noticed a that when i open either my door or the passengers(single cab truck) my sub is audibly louder to any music, especially at high volumes. Im currently running 2 3in aeros at 33Hz, should i switch over to some 4in aeros? How can i make my sub sound that much louder with doors shut

Its an OA 12 in 2.2cu^ft net @ 33Hz

Falcons
06-26-2012, 10:12 PM
You have roughly 44 square inches of port unless my iPhones calculator is being dumb again and I'm wrong lol. But in a single cab truck whenever you put a system in it the cabin is so small it can become a box in itself.

JoshC
06-26-2012, 10:15 PM
You have roughly 44 square inches of port unless my iPhones calculator is being dumb again and I'm wrong lol. But in a single cab truck whenever you put a system in it the cabin is so small it can become a box in itself.

lol ok but that didnt answer my question, i have atleaste a +3db gain with door open. What do i need to do to my box to gain that without doors open

CAT MAN
06-26-2012, 10:16 PM
lol ok but that didnt answer my question, i have atleaste a +3db gain with door open. What do i need to do to my box to gain that without doors open

max out the box with testing. after sealing my wall im still louder trunk open :/

RangerDangerV2
06-26-2012, 10:16 PM
same thing with the danger ranger.... no matter what there really just isnt enough volume in the cabin. when you open the door that make the sub see a larger volume in front of the cone. this makes it so the sub isnt fighting itself, when the truck is sealed up the front wave has too much pressure in front of it to move enough, so the rear and front waves fight eachother... try a larger enclosure with more port. that may work.

JoshC
06-26-2012, 10:21 PM
max out the box with testing. after sealing my wall im still louder trunk open :/


same thing with the danger ranger.... no matter what there really just isnt enough volume in the cabin. when you open the door that make the sub see a larger volume in front of the cone. this makes it so the sub isnt fighting itself, when the truck is sealed up the front wave has too much pressure in front of it to move enough, so the rear and front waves fight eachother... try a larger enclosure with more port. that may work.

hmmm ok, well ive talked to box man a bit about it. He thinks we can rebuild and do better but im not positive about anything yet lol. But i did get my windows tinted lol

wilson
06-26-2012, 10:22 PM
You have roughly 44 square inches of port unless my iPhones calculator is being dumb again and I'm wrong lol. But in a single cab truck whenever you put a system in it the cabin is so small it can become a box in itself.

2 3in aeros is ~14 sq inches, unless I'm wrong.

RangerDangerV2
06-26-2012, 10:26 PM
try a slot port design as well, aeros are good for keeping pressure up, but you need exactly the opposite.

hispls
06-26-2012, 10:30 PM
So ive noticed a that when i open either my door or the passengers(single cab truck) my sub is audibly louder to any music, especially at high volumes. Im currently running 2 3in aeros at 33Hz, should i switch over to some 4in aeros? How can i make my sub sound that much louder with doors shut

Its an OA 12 in 2.2cu^ft net @ 33Hz

Pretty common for that type of vehicle. Possibly more port area will help, but I wouldn't expect miracles.

---------- Post added at 10:30 PM ---------- Previous post was at 10:30 PM ----------


So ive noticed a that when i open either my door or the passengers(single cab truck) my sub is audibly louder to any music, especially at high volumes. Im currently running 2 3in aeros at 33Hz, should i switch over to some 4in aeros? How can i make my sub sound that much louder with doors shut

Its an OA 12 in 2.2cu^ft net @ 33Hz

Pretty common for that type of vehicle. Possibly more port area will help, but I wouldn't expect miracles.

Falcons
06-26-2012, 10:46 PM
2 3in aeros is ~14 sq inches, unless I'm wrong.

your probably right man, like i said my iphone calculator ***** because i cant use parenthesis.

Kangaroux
06-26-2012, 10:49 PM
Has to do with cancellation and phasing issues. Nearly every vehicle I've seen is louder with a door open. I've had 5 different setups for my pathfinder and all of them were loudest with one of the windows down

RangerDangerV2
06-26-2012, 10:51 PM
Has to do with cancellation and phasing issues. Nearly every vehicle I've seen is louder with a door open. I've had 5 different setups for my pathfinder and all of them were loudest with one of the windows down

I gain almost 10dbeez with my driver door open.

Phoenix Risen
06-26-2012, 10:56 PM
i gain 4-6 depending on the system im running, port area is part of it, but it also has a lot to do with the vehicle,

a tahoe that i meter looses a good 4db by when something is open. it just how things work,

and you are a good bit short on port area, i would say at the least add another 3", but it would probably be better to go with a pair of 4" or a single 6"... how much power?

cyn
06-26-2012, 11:01 PM
my car out of trunk seats up with any window or sunroof open is "Louder" ear wise by a good 20-30% ... so its not just trucks etc..

BrownVanMan
06-26-2012, 11:33 PM
My 94 olds was much louder with the widows/doors open.

However my single cab Toyota pickup with a center consoul box, to the ear, gets quieter by a whole lot if both windows and rear sliding window is open. But with it opened up the windows and rear view move a lot more but to my ear get much quieter? All cars/trucks are different.

travicles
06-26-2012, 11:33 PM
Haha get used to it. I also have a regular cab truck, and the bass is so much louder with both windows open. It is unfortunate, I know.

T3mpest
06-26-2012, 11:40 PM
Opening doors and windows allows the windows to function as ports.. The car itself adds ALOT to the bass.. Remember, most setups that do 150's in walls wouldn't do more than a 125 or 130 if you measured it in a empty field from the same distance away.. 30db's of gain, which is common due to cabin gain, is like adding 10,000 watts of power to speaker.. Really for a daily driver you can't do much to fix this phenomenon, just realize that it's all part of a much larger gain structure that is already working in your favor.
ss

Phoenix Risen
06-26-2012, 11:41 PM
its just acoustics, if you really work with the vehicle you can find the way around it though.

Mitch86
06-27-2012, 12:24 AM
My truck ***** sealed up to the point that its barely audible, but roll down a window and it rattles your eyes. (Depending on the set up) Not sure that you can really do anything about it either. I have had all kinds of set ups and all of them were the same way.

mylows10
06-27-2012, 12:40 AM
it has to do with what the resonant frequency is of your truck the closer to that frequency the louder you'll be with the windows up,the farther from that frequency the lower you db's will be sealed.

JoshC
06-27-2012, 12:51 AM
i gain 4-6 depending on the system im running, port area is part of it, but it also has a lot to do with the vehicle,

a tahoe that i meter looses a good 4db by when something is open. it just how things work,

and you are a good bit short on port area, i would say at the least add another 3", but it would probably be better to go with a pair of 4" or a single 6"... how much power?

Im considering going to 2 4in ports, it would be a pain to redo my box to a large slot port but maybe my dudes up to it. I have 1.2K on tap but my OA dosnt want more then 800 or so in that box. Both SPL audio and the guys at OA said the box was rather large. But my builder wanted a very low resident Fq for the box since i want my lows as loud as possible lol so it just dosnt take as much powa


Haha get used to it. I also have a regular cab truck, and the bass is so much louder with both windows open. It is unfortunate, I know.

No its opposite for me. My bass gets a bit better/deeper with windows down, but you open a door and it gains 3-5db(maybe more). Deff a good audible change, very noticeable to anyone in the car.

So after reading everything looks like it time to redo the box for more port and possibly take some space out. Thinking ill make the box 1.9-2cu^ft @ 30Hz with 2 4in aeros or a slot port. May just end up doing a whole new box, but if i decide to go that route ill probably switch to 2 10s

Lots of responses and good info, thanks guys. Ill be sure to post up a log of whatever i end up doing

EDIT: also considering going to a bigger 12, 1-1.5Krms area

RangerDangerV2
06-27-2012, 01:24 AM
Im considering going to 2 4in ports, it would be a pain to redo my box to a large slot port but maybe my dudes up to it. I have 1.2K on tap but my OA dosnt want more then 800 or so in that box. Both SPL audio and the guys at OA said the box was rather large. But my builder wanted a very low resident Fq for the box since i want my lows as loud as possible lol so it just dosnt take as much powa


No its opposite for me. My bass gets a bit better/deeper with windows down, but you open a door and it gains 3-5db(maybe more). Deff a good audible change, very noticeable to anyone in the car.

So after reading everything looks like it time to redo the box for more port and possibly take some space out. Thinking ill make the box 1.9-2cu^ft @ 30Hz with 2 4in aeros or a slot port. May just end up doing a whole new box, but if i decide to go that route ill probably switch to 2 10s

Lots of responses and good info, thanks guys. Ill be sure to post up a log of whatever i end up doing

EDIT: also considering going to a bigger 12, 1-1.5Krms area

go with a slot port, you want to try to keep the cabin pressure down...

supermaxx123
06-27-2012, 01:36 AM
I've never actually tried playing my system with the doors open and me inside. Reg cab truck so the space is tiny but so is my box!. For 2.2 cubes 2 3" port ports won't cut it imo. I'm running 12"^2 of port in .7cu/ft. I get no port noise and tuned to 37hz my bottom end bottoms out at 28hz

The_Grimy_One
06-27-2012, 01:57 AM
your probably right man, like i said my iphone calculator ***** because i cant use parenthesis.

WHAT iPhone do you have???

Blue Fury
06-27-2012, 01:59 AM
go with a slot port, you want to try to keep the cabin pressure down...

What? How would a slot port help keep the pressure down vs an aero port? And isn't his goal about increasing the SPL with the doors shut.. not decreasing it?




Don't just switch out your ports for something you think will work. Who designed your box? Depending on the flare that the port has, you've got a very small window of what will work for what you want it tuned to. 14sqin for 2.2cft is on the low side. If you increase the area, you have to increase the length to maintain the tuning. If you increase the length but don't increase the box size, you decrease the net volume consequently requiring less port area. Then you have to iterate a few times to find the right area/length/volume combo. It's less headache to make a new box.
You say you want 2 4" aeros at 30hz from 2 3" aeros at 33hz. You're going to have a significantly bigger box even after the 0.3cft reduction. And if you're lowering the tuning, the probability is very high that you wont get the loudness you're looking for with the door shut since you're likely tuning away from your cabin gain freq. If you tuned upward, you'd get that loudness but skimp the <30 hz's. You'll definitely get lower and shake your balls a little more on the low notes if you went for 30 hz tuning, but you might be disappointed with this decision if you want to be louder with the doors shut compared to your current situation.

RangerDangerV2
06-27-2012, 02:17 AM
What? How would a slot port help keep the pressure down vs an aero port? And isn't his goal about increasing the SPL with the doors shut.. not decreasing it?




Don't just switch out your ports for something you think will work. Who designed your box? Depending on the flare that the port has, you've got a very small window of what will work for what you want it tuned to. 14sqin for 2.2cft is on the low side. If you increase the area, you have to increase the length to maintain the tuning. If you increase the length but don't increase the box size, you decrease the net volume consequently requiring less port area. Then you have to iterate a few times to find the right area/length/volume combo. It's less headache to make a new box.
You say you want 2 4" aeros at 30hz from 2 3" aeros at 33hz. You're going to have a significantly bigger box even after the 0.3cft reduction. And if you're lowering the tuning, the probability is very high that you wont get the loudness you're looking for with the door shut since you're likely tuning away from your cabin gain freq. If you tuned upward, you'd get that loudness but skimp the <30 hz's. You'll definitely get lower and shake your balls a little more on the low notes if you went for 30 hz tuning, but you might be disappointed with this decision if you want to be louder with the doors shut compared to your current situation.

what I have been told is that aeros are really good for keeping cabin pressure up... in this case, the op doesnt want more cabin pressure because that is more pressure against the front wave of the cone... if he has less cabin pressure (open door) the subwoofer doesnt have to "work" as hard as it does sealed.. but I could be wrong.

Blue Fury
06-27-2012, 02:31 AM
You're on the right track but in a nutshell it's like this. You open the door, the door is the new 'port' where the cabin is the enclosure. It was mentioned already. It's like increasing the order of the enclosure if you count the cabin as an enclosure in itself.

Idk who told you that about aeros, he might have been stoned. Aeros are for reducing turbulence with a byproduct of reducing actual port length by a minimal amount. Aeros, from reducing turbulence, have an effect of essentially increasing the port area by a minimal amount. That's why you see boxes with aero's with a smaller port area than those with non-aero.

JoshC
06-27-2012, 03:45 AM
What? How would a slot port help keep the pressure down vs an aero port? And isn't his goal about increasing the SPL with the doors shut.. not decreasing it?




Don't just switch out your ports for something you think will work. Who designed your box? Depending on the flare that the port has, you've got a very small window of what will work for what you want it tuned to. 14sqin for 2.2cft is on the low side. If you increase the area, you have to increase the length to maintain the tuning. If you increase the length but don't increase the box size, you decrease the net volume consequently requiring less port area. Then you have to iterate a few times to find the right area/length/volume combo. It's less headache to make a new box.
You say you want 2 4" aeros at 30hz from 2 3" aeros at 33hz. You're going to have a significantly bigger box even after the 0.3cft reduction. And if you're lowering the tuning, the probability is very high that you wont get the loudness you're looking for with the door shut since you're likely tuning away from your cabin gain freq. If you tuned upward, you'd get that loudness but skimp the <30 hz's. You'll definitely get lower and shake your balls a little more on the low notes if you went for 30 hz tuning, but you might be disappointed with this decision if you want to be louder with the doors shut compared to your current situation.

Well i can open the box up to accommodate for larger ports but switching to slot would be a pain and not likely worth it. Honestly the options that wouldnt be to difficult to do is go 1in bigger on the ports. If thats not really a good option i might as well do 2 10s(get 500-600wrms a pop), or do you think i could do just as well with a 1-1.5k 12? I could just get a bigger 12 then do a new box or vice versa

audiobaun
06-27-2012, 03:57 AM
I have found out as today, that my new box with the slot ports verses the aero ports seem to give me better sound,and fantastic pressure levels,and much better with the windows down at halfway, just on a pair atm,,its insane,and ive done seperate chambers this time, and to me sounds so much better..1 pair of 10s,tomorrow the other 2 will be up and running..Ive been concerned about the airbags in the dash, and the steering wheel already,hoping they do not release.My tens sound great, but i am in an xcab..I did do 4 svc tens in a single cab before,all in sealed boxes,and sounded fantastic,,were Kicker Stillwater,on a Hifonics VII Boltar,in a 87 Toyota truck

Falcons
06-27-2012, 08:04 AM
WHAT iPhone do you have???

iPhone 4 lol. When I type in a=pi*r^2 it squares the whole thing. So if I had done it properly I would have had to square the radius then multiply by pi. It's not that complicated just annoying lol

Blue Fury
06-27-2012, 01:29 PM
Well i can open the box up to accommodate for larger ports but switching to slot would be a pain and not likely worth it. Honestly the options that wouldnt be to difficult to do is go 1in bigger on the ports. If thats not really a good option i might as well do 2 10s(get 500-600wrms a pop), or do you think i could do just as well with a 1-1.5k 12? I could just get a bigger 12 then do a new box or vice versa

I think you'll be chasing a dragon until you make a complete change in your setup.

The_Grimy_One
06-27-2012, 03:14 PM
Theres no parentheses when u turn it side ways???

RangerDangerV2
06-27-2012, 03:21 PM
hmm.. this thread is very interesting and hopefully will help me get that 150 sealed in my ext cab... on music.

bhsdriller
06-27-2012, 03:29 PM
you can try a new box, but I dont think it would help much...that's how single cabs are

my ext. cab is like that too. Probably loose 3-5 dbs sealed up

RangerDangerV2
06-27-2012, 03:36 PM
you can try a new box, but I dont think it would help much...that's how single cabs are

my ext. cab is like that too. Probably loose 3-5 dbs sealed up

same here... I think a 150 sealed is possible in my ranger though... I have a decent amount of cone area, decent power, and plenty of port...

bhsdriller
06-27-2012, 03:41 PM
I compete in meca....doing a 52. And I might be able to do a 50 sealed up on a tone, maybe. Music probably wouldn't be close lol

RangerDangerV2
06-27-2012, 03:45 PM
I compete in meca....doing a 52. And I might be able to do a 50 sealed up on a tone, maybe. Music probably wouldn't be close lol

ill "try" for it but nobody that ive heard of puts up big numbers sealed in ext cabs except Bojangles.. lol Ill def have a 50 outlaw though... Its a demo truck anyway so sealed score really isnt a big deal...

RangerDangerV2
06-27-2012, 03:45 PM
I compete in meca....doing a 52. And I might be able to do a 50 sealed up on a tone, maybe. Music probably wouldn't be close lol

ill "try" for it but nobody that ive heard of puts up big numbers sealed in ext cabs except Bojangles.. lol Ill def have a 50 outlaw though... Its a demo truck anyway so sealed score really isnt a big deal...

bhsdriller
06-27-2012, 03:55 PM
ill "try" for it but nobody that ive heard of puts up big numbers sealed in ext cabs except Bojangles.. lol Ill def have a 50 outlaw though... Its a demo truck anyway so sealed score really isnt a big deal...

have you been on a meter yet? Buddy has 2 15's on a bc3500 in a ranger, it does good

RangerDangerV2
06-27-2012, 04:07 PM
have you been on a meter yet? Buddy has 2 15's on a bc3500 in a ranger, it does good

not yet.. havent gone full power yet.. but Im building a new box, then I will do some testing between the 2 and make a choice from those two sets of numbers... looking back I should have gone with 2 15s... but we will see what that apxx will do...

Julian
06-27-2012, 04:17 PM
Basically your car works as a 6th order bandpass.

RangerDangerV2
06-27-2012, 04:18 PM
Basically your car works as a 6th order bandpass.

not even close.

wenn_du_weinst
06-27-2012, 04:24 PM
wow a ton of wrong info on here.

I think Kangaroux is the only one I saw that got it right.
It's not your windows acting as a port, it's not your cabin acting like an enclosure. It is all to do with wave lengths and phasing. A full length bass wave is much longer then the distance from your subwoofers to windshield. This causes it to double back, and go back forward again, until it reaches maturity and loses strength. This Causes it to become 180 degree's out of phase with the forward moving wave canceling each other out. Opening your windows lowers the amount of the bass waves coming back at the source as it lets them escape out the window. It is 100% to do with cancellation, once you get the perfect alignment between the subwoofer and listening area you are golden. Have you ever noticed that even with very low scores that HT subwoofers are much louder to the ear? That's because they don't suffer the same problem as an in car sub.

Blue Fury
06-27-2012, 04:25 PM
not even close.

Closer than you might think..
The Subwoofer DIY Page - 6th Order Bandpass Systems (http://www.diysubwoofers.org/bnd/6thord4.htm)

Julian
06-27-2012, 04:27 PM
Closer than you might think..
The Subwoofer DIY Page - 6th Order Bandpass Systems (http://www.diysubwoofers.org/bnd/6thord4.htm)


Exactly :) Ignorant people so quick to say I'm wrong.

Yes in effect your car is working as a 6th order bandpass.. Some cars work but not all cars.. If you get louder with windows open in effect it's a 6th order.

wenn_du_weinst
06-27-2012, 04:28 PM
Technically it is a very poorly sealed 6th order, but only with you sitting inside the ''enclosure''
That does not mean you can how ever model your car/system as a 6th order to see what will happen.

RangerDangerV2
06-27-2012, 04:29 PM
Exactly :) Ignorant people so quick to say I'm wrong.

Yes in effect your car is working as a 6th order bandpass.. Some cars work but not all cars.. If you get louder with windows open in effect it's a 6th order.

still wrong. read wdw's post.

RangerDangerV2
06-27-2012, 04:30 PM
wow a ton of wrong info on here.

I think Kangaroux is the only one I saw that got it right.
It's not your windows acting as a port, it's not your cabin acting like an enclosure. It is all to do with wave lengths and phasing. A full length bass wave is much longer then the distance from your subwoofers to windshield. This causes it to double back, and go back forward again, until it reaches maturity and loses strength. This Causes it to become 180 degree's out of phase with the forward moving wave canceling each other out. Opening your windows lowers the amount of the bass waves coming back at the source as it lets them escape out the window. It is 100% to do with cancellation, once you get the perfect alignment between the subwoofer and listening area you are golden. Have you ever noticed that even with very low scores that HT subwoofers are much louder to the ear? That's because they don't suffer the same problem as an in car sub.

how does one accomplish this??

Julian
06-27-2012, 04:31 PM
I am i Still wrong? It is in-effect working as a 6th order..

wenn_du_weinst
06-27-2012, 04:32 PM
how does one accomplish this??

Ask a burp car guy, testing and testing, and then more testing.

I am i Still wrong? It is in-effect working as a 6th order..

like I said before, technically but not a very good one and you would be inside the 2nd chamber.

Blue Fury
06-27-2012, 04:47 PM
Technically it is a very poorly sealed 6th order, but only with you sitting inside the ''enclosure''
That does not mean you can how ever model your car/system as a 6th order to see what will happen.

Right, I'm not saying it's exactly, just close to. But the effect is still there. I don't know enough on the long wavelength % change when the longest path (rear to front windsheild) changes to rear to effectively infinite length with the door open so I left that alone. Same with cancellation.. idk the degree to which it's affected at what % or area that opens up from doors or windows. I'm not sure anyone does unless he/she has some substantial acoustical engineering education.

wenn_du_weinst
06-27-2012, 04:50 PM
I have a general understanding on the subject. It's not all that difficult to understand but it's not really needed to know it.

Blue Fury
06-27-2012, 05:07 PM
I have a general understanding on the subject. It's not all that difficult to understand but it's not really needed to know it.

Lol you said it. When I was balls deep in this hobby, I started to learn about it but stopped because I couldn't imagine a time where I would need to build an enclosure for myself that took all of this into effect when no one is paying me to do so.

JoshC
06-27-2012, 06:43 PM
So that means i need to switch to 2 10s with slot port and open my amp up the rest of the way to hear a decent change

Blue Fury
06-27-2012, 07:01 PM
Model them both with the linkwitz transform on winISD to find your theoretical change. I wouldn't waste my time if it doesn't even increase 3db. Then again, it's theoretical change.

JoshC
06-27-2012, 07:10 PM
Model them both with the linkwitz transform on winISD to find your theoretical change. I wouldn't waste my time if it doesn't even increase 3db. Then again, it's theoretical change.

I dont see how more cone area and more power wouldnt yield more db. Ill let my builder run the programs lol, possibly contact ram_designs for some prints. But i just saw vegafans old schools RE 10s for sale. 3in VC and Fs of 26.6 :yumyum:

Blue Fury
06-27-2012, 07:42 PM
I dont see how more cone area and more power wouldnt yield more db. Ill let my builder run the programs lol, possibly contact ram_designs for some prints. But i just saw vegafans old schools RE 10s for sale. 3in VC and Fs of 26.6 :yumyum:

It should result in higher spl but I don't think that the small gain will be worth the effort.

It's too bad you can't fit the Xcons and box I have for sale in your truck. They'll massage your nuts nicely

Julian
06-27-2012, 07:45 PM
It should result in higher spl but I don't think that the small gain will be worth the effort.

It's too bad you can't fit the Xcons and box I have for sale in your truck. They'll massage your nuts nicely
How will 8 xcon 10's massage my nuts?
:lol:
8 in my car... team ssa ftw