Port placement????

[kush-divinity 10+ year member]

Does it matter where the port is placed on the box?

Not a normal SUV style box, but a full wall.

Im thinking 4 18's, so would I be best to do a box-style slot port in each upper corner? Or put the subs to one side and run a port all the way down the drivers side? Or maybe a huge port in the center of the box. All ideas are easily built, but I want to know whether it will make a difference in sound.

This is not going to be a huge powered system, so there is no real need for 400in of port. I was thinking maybe a 5x40 on one side, or a 10x10 in each corner. I am kind of confused.

I can go up to 24ft3 easy, so space isn't really an issue with port length.

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[azimuth 5,000+ posts]

it doesn't matter where they are, as long as they match each other in size, and length, and are tuned right.

 

[azimuth 5,000+ posts]

and you will still need port area regarless of power. it's depends more on internal box space.

 

[kush-divinity 10+ year member]

I know the "rules" of port area vs. volume.

But, in my experience, low powered systems seem to have flatter response with a port that is a tad too small. All my builds are for daily use. I listen to older rap and country, and use my epicenter alot. My concern is the 25-40hz range, any higher is taken care of by a pair of sealed Memphis PR10, bandpassed from 50-125hz.

My big wonder is: 4 very sensitive 18's or 15's playing only 25-45 hz, do I really need a massive port? Im not trying for a hair trick. I just want to look "cute", but not overplay my mids. I want to roll an extremely flat curve, maybe increasing from 35 and lower. I want a rumble.

Maybe, I would better served with a sealed box?

Here is reasoning to low power: I am limited to 550rms @ 1ohm, and 1100 @ .5ohm. My amp will play at full volume all day at .5ohm without overheating. I am still debating on my subwoofer choice, as nice, cheap, low requirement 18's are hard to find.

 

[azimuth 5,000+ posts]

I know the "rules" of port area vs. volume.
But, in my experience, low powered systems seem to have flatter response with a port that is a tad too small. All my builds are for daily use. I listen to older rap and country, and use my epicenter alot. My concern is the 25-40hz range, any higher is taken care of by a pair of sealed Memphis PR10, bandpassed from 50-125hz.

My big wonder is: 4 very sensitive 18's or 15's playing only 25-45 hz, do I really need a massive port? Im not trying for a hair trick. I just want to look "cute", but not overplay my mids. I want to roll an extremely flat curve, maybe increasing from 35 and lower. I want a rumble.

Maybe, I would better served with a sealed box?

Here is reasoning to low power: I am limited to 550rms @ 1ohm, and 1100 @ .5ohm. My amp will play at full volume all day at .5ohm without overheating. I am still debating on my subwoofer choice, as nice, cheap, low requirement 18's are hard to find.

i would stick on the lower end of the rule. 10-12 sq. inches per foot. i agree that you won't need 16 inches per square foot, but i would at least do 10 still.

 

[RAM_Designs 5,000+ posts]

You're doing 4 18's walled, yet you don't want it to overpower a pair of 10's you have playing midbass? If I were you I'd get an IXL18, put it in a big ported box tuned to the low 20's, and build your own 4th order LP crossover to where you want it to be since most amp's LP crossovers aren't very steep and still let some higher frequencies in.

 

[kush-divinity 10+ year member]

The 18's will NOT be fully driven. They are more for a "show effect". And for solid response down low. I am not even looking to break into the 140's. If that clears it up.

This is an odd project, that I am sure none of you will understand without seeing firsthand what I need.

Thank you for the answer on 10-12 in per foot. That is close to what I had in mind. I was thinking 16-18ft, with 200in of port.

This is simply a pretty project, with a stained birch face to match my CB rack and my rear console I made. The rear will all be invisible to lookers, as I have tinted ALL my windows with 2 layers of Optic Technologies 3% limo over a layer of 35% silver mirror. It is quite dark //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I just want to do 4 18's, and I am not worried with SPL by any means, just a very clear low end extesion down in the 20's.

 

[azimuth 5,000+ posts]

The 18's will NOT be fully driven. They are more for a "show effect". And for solid response down low. I am not even looking to break into the 140's. If that clears it up.
This is an odd project, that I am sure none of you will understand without seeing firsthand what I need.

Thank you for the answer on 10-12 in per foot. That is close to what I had in mind. I was thinking 16-18ft, with 200in of port.

This is simply a pretty project, with a stained birch face to match my CB rack and my rear console I made. The rear will all be invisible to lookers, as I have tinted ALL my windows with 2 layers of Optic Technologies 3% limo over a layer of 35% silver mirror. It is quite dark //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I just want to do 4 18's, and I am not worried with SPL by any means, just a very clear low end extesion down in the 20's.

i must be missing something. if you already have the 4 18's, why not make it pound? i understand that spl isn't what you're going for, but if you build the box right, it'll still pound really hard, even on lower power. you could probably screw it up bad and still make 140.

 

[kush-divinity 10+ year member]

Ah, no I don't have the 18's, I am looking for some. No one around here has ran 18's since the mid-90's. Everyone is on the Memphis scene, running 1 or 2 PR12 off of a Walmart amp. I simply want a very musical enclosure, even if it is very quiet. And I am fully aware that with that much cone area, I can get loud if I desire.

I may end up settling for 4 15's in the end, though it may perform as well or better than my idea of 18's, it wont have that "OMFG" factor when looking at them.

I am leaning towards 4 peavey lowriders, but the single 8ohm coils throw me off.......

I must get to a .5ohm load if I want any decent power to drive them.

Or, as my retarded brother in law tells me now, I should run 8 cheap 12's ported.

My only wonder before planning was whether the placement of thew port would affect my sound any. I would prefer to run 1 large port as opposed to 2 smaller ones.

 

[azimuth 5,000+ posts]

Ah, no I don't have the 18's, I am looking for some. No one around here has ran 18's since the mid-90's. Everyone is on the Memphis scene, running 1 or 2 PR12 off of a Walmart amp. I simply want a very musical enclosure, even if it is very quiet. And I am fully aware that with that much cone area, I can get loud if I desire.
I may end up settling for 4 15's in the end, though it may perform as well or better than my idea of 18's, it wont have that "OMFG" factor when looking at them.

I am leaning towards 4 peavey lowriders, but the single 8ohm coils throw me off.......

I must get to a .5ohm load if I want any decent power to drive them.

Or, as my retarded brother in law tells me now, I should run 8 cheap 12's ported.

My only wonder before planning was whether the placement of thew port would affect my sound any. I would prefer to run 1 large port as opposed to 2 smaller ones.

port placement would make a difference on a meter, but as a daily driver, not really. as long as firing direction stays the same, it won't matter much if it's passenger or driver side.

 

[kush-divinity 10+ year member]

Thank you for the answer. We have been debating this all day. I have decided to put the port at the top of the box. 6 inches high, 42 inches wide, and as deep as needed for a 30hz tune. I am going to make it step out at the bottom, and use the platform as an amp rack.

 

[killabazz88]

use these MA 18's there cheap but will pound way harder than pyles and still give u a .5 ohm load 300-400 watts will make them sound good //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=20088

 

[kush-divinity 10+ year member]

Oh man, that's an ugly subwoofer. And a non-pressed paper cone? At $140 each I'll pass, but thanks. I can get SoundStream T1-15's local for 90 each..... cash paid and real customer service. I read that that site has awful CS.

And I love your diss on Pyles. Cheap subs, but they have 1 good model.......

 

[blackbonnie 5,000+ posts]

Oh man, that's an ugly subwoofer. And a non-pressed paper cone? At $140 each I'll pass, but thanks. I can get SoundStream T1-15's local for 90 each..... cash paid and real customer service. I read that that site has awful CS.
And I love your diss on Pyles. Cheap subs, but they have 1 good model

.......

really? care to elaborate....

 

[kush-divinity 10+ year member]

Yeah, the Red Label SQ-12.

Maybe not the most awesome woofer ever....but it is a clone of the Kicker L7. A very **** close clone. Sounds exactly the same when swapping 1 for 1 in an in-car enclosure. A very tough woofer that can handle way over its 750rms rating forever. A man would almost be tricked into thinking these were actually made in Stillwater.........