ported box question?

[necros0819]

I'm thinking of getting another box for my Alpine SWR 12D4 Sub and was wondering if anyone here has this same sub and also if I should have the port face the hatch and sub face up or Sub and port facing the hatch.
Or any advice really would help.I also want it tuned for SPL and SQ.I listen to Hip Hop and sometimes Dub Step and Pop music but definitely more Hip Hop.
Thanks!

[rajin929]

i know every car is different, but with hatchbacks i've had good experience with the sub and port facing the back of the car/hatch

[necros0819]

Yeah Ive tried moving my current box every which way and it does seem to make it louder when facing the hatch but also the rattling is much more noticeable as well.
Today I turned the box with the sub up and port up and it sounds more boomier ,not as loud but the rattle is not that noticeable.That's why I was wondering if Sub up and port toward the hatch would be better.

[DLYDRVN]

Theoretically the orientation of the box shouldn't matter inside a car cabin. Ported or otherwise. You might get a small change in sound because there may be slightly more volume due to a change in distance or possibly a minor phase shift... But realistically speaking in a space the size of a car cabin, distance should be the only thing that matters, not orientation.

[Default User]

Don't bother with a type S

Go with a single Type R or Type X
Or go with some JL12w7's, RE's or Mmmats if you can stil find em

[CelestSpeed3]

Theoretically the orientation of the box shouldn't matter inside a car cabin. Ported or otherwise. You might get a small change in sound because there may be slightly more volume due to a change in distance or possibly a minor phase shift... But realistically speaking in a space the size of a car cabin, distance should be the only thing that matters, not orientation.

Can you explain more on the distance reference you mentioned please.

[SomeGuy]

They should be in the same plane at very least, both up or both back...90 degree offset will result in more chances of cancellation between the wave fronts.

Celest - A car is smaller than eighth space (full space is floating in the air, half space is on the floor, quarter space is next to a wall on the floor and eighth space is in a corner)...at which point you have a shit ton of gain anyway, so the direction it's facing won't make much of a difference unless there are strange cancellations or huge amounts of restriction blocking things off.

For every doubling of distance between the source and the listener results in approximately a 3db decrease in apparent sound level.

[Genpu_Mz3]

Don't bother with a type S

Go with a single Type R or Type X
Or go with some JL12w7's, RE's or Mmmats if you can stil find em
:hawt Mmmats :) had an opportunity to own a cpl 12's a few years back, too bad they were in a cheap bandpass box, so i opted for 12" kaption audio instead, very solid canadian brand.


Can you explain more on the distance reference you mentioned please.

if you have a home theatre stand infront of it with the sub on and music playing, then go upstairs/downstairs or just another part of the room, you will notice the subwoofer gets deeper as theres more room for sound to move

[Wisecraker]

I would say facing out towards the hatch, and I have a personal preference for a ported box. I find that my ported box allows more distinguishable bass for heavy bass dub step and electronic music, instead of the song sounding like one big "Bass Cannon, Bass Cannon!"

http://m.youtube.com/watch?v=Htm_956k5ps&desktop_uri=%2Fwatch%3Fv%3DHtm_956k5ps

[DLYDRVN]

Celest - A car is smaller than eighth space (full space is floating in the air, half space is on the floor, quarter space is next to a wall on the floor and eighth space is in a corner)...at which point you have a shit ton of gain anyway, so the direction it's facing won't make much of a difference unless there are strange cancellations or huge amounts of restriction blocking things off.

For every doubling of distance between the source and the listener results in approximately a 3db decrease in apparent sound level.

Basically this. Someone above also mentioned space for waves to develop, which is part of the quarter wavelength rule... Anyway a car is basically a super small room. And it's more about absolute pressure changes inside the box than about room acoustics, but this article will give you an idea of how low frequencies behave and why, in a car, it's not really going to matter what orientation your sub is in short of placing it beside your head.

http://www.moultonlabs.com/more/taming_the_big_wave/P1/


As far as ported v.s. sealed as a general rule:

Ported: Plays louder at and around/above the port's tuned frequency. Less mechanical power handling (more chance of boom). And become increasingly useless as you move below Fs/Port frequency. Also not really accurate. Great for impact though.

Sealed: Plays deeper, safer and sounds better. Not as much impact though.

[Wisecraker]

Basically this. Someone above also mentioned space for waves to develop, which is part of the quarter wavelength rule... Anyway a car is basically a super small room. And it's more about absolute pressure changes inside the box than about room acoustics, but this article will give you an idea of how low frequencies behave and why, in a car, it's not really going to matter what orientation your sub is in short of placing it beside your head.

http://www.moultonlabs.com/more/taming_the_big_wave/P1/


As far as ported v.s. sealed as a general rule:

Ported: Plays louder at and around/above the port's tuned frequency. Less mechanical power handling (more chance of boom). And become increasingly useless as you move below Fs/Port frequency. Also not really accurate. Great for impact though.

Sealed: Plays deeper, safer and sounds better. Not as much impact though.

Great information. Not to sound like a jerk but I would say although there is a lot of proven science behind how sound, and sound waves work, in the end it's personal preference. So maybe the OP can somehow hear how the same song sounds out of two different types of boxes and chooses the one they prefer. I have preferred ported and have used ported boxes for almost 10 years, but I have buddies that have preferred enclosed instead.

[DLYDRVN]

Oh this wasn't meant to imply ported vs sealed was better vs worse. Simply wanted to point out the general difference between them.

I've had both ported and sealed designs in my studio reference subs and liked them both for different reasons. I find ported is nice in a home theatre set up where you want to 'hear' the sub where as sealed is a bit more seamless. Application and preference will of course come into play.

As far as placement goes tho, those rules are dictate by physics. There may be a preference in what you're hearing but again, in a normal small space with all else equal, there shouldn't be a difference in orientation

[Wisecraker]

Oh this wasn't meant to imply ported vs sealed was better vs worse. Simply wanted to point out the general difference between them.

I've had both ported and sealed designs in my studio reference subs and liked them both for different reasons. I find ported is nice in a home theatre set up where you want to 'hear' the sub where as sealed is a bit more seamless. Application and preference will of course come into play.

As far as placement goes tho, those rules are dictate by physics. There may be a preference in what you're hearing but again, in a normal small space with all else equal, there shouldn't be a difference in orientation

I didn't take it like that. No worries. It's good to have all the info.

[JayJay18]

Email Alpine and ask for a box build sheet.
They give you extact dimensions for the size of box, port size and length of port aswell.
Up or down is no different, internal car volume is to small for direction to have a major impact.
The only thing that makes a difference is port design, sloted or circular, longer or shorter, wider or narrower, depends on how you want your subwoofer tuned.
But the specs Alpine provides are optimal and should be used

[necros0819]

As always great info guys will help tremendously for sure. Just got a hold of a used pioneer 4 volt car deck and a |Line driver so I will be busy getting those in my hatchback.
Also I wanted to ask as well people that own hatchback what do they do about the security cover in the back.Mine rattles like crazy once I turn up the volume and just makes it sound like shit. Sometimes I take it off and it sounds great with out it but i dont feel comfortable people seeing my stuff back there as I dont have tinted windows.

Cheers Everyone!

[Lumberjack]

1. Low frequencies are "omni-directional" and it doesn't matter really which direction you point the sub. An easy trick is to change the phase of the frequency is to reverse the polarity of the speaker wires and see if it makes a difference where you sit listening.
2. Ported enclosures have a 3db gain vs. sealed enclosures and can generally play lower but can bottom out easier and risk damaging.
3. Sealed enclosures can handle higher wattage and are generally tighter response. You also require a smaller enclosure vs ported.
4. To get a 3db gain in sound you must double the power generally speaking.