diff more or less volume in box

Ok,

I have two Alpine Type R @ 4 Ohms subwoofers.

I am looking for a ported box design.  The specs for the subwoofers are between 1.5ft^3 - 3.5ft^3 (adding the two volumes together).

I am looking at two different boxes.  Assume mounting will be normal (magnet in box) and taking into consideration the displacement of the sub and magnet here are the specs of the two separate boxes:

Q-Logic QLH-1.2512DS = 2.358ft^3

Q-Logic GLH-1.7512DS = 3.358ft^3

They are both within the recommended volums for a ported box.

What is the difference between more air versus less air?

In terms of sound quality, clarity, loudness, force, etc?

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Tyler B.

I would think sq wise the subs would be slightly more responsive but it they would still drop down low in that smaller box. If you want clarity (very quick response) than go sealed but between those two, again the smaller box. I would think the bigger box would be louder. Force? Pressure wise? Again I think the bigger one would be louder. Expand on your "etc.". What kind of music do you listen to? Comp.? Daily driver? What is the vehicle? Are the ports the same size on these different sized boxes? Why did you choose to go ported???
Now when you say the recommended box size was 1.5 - 3.5 is this ported or sealed. Ported is always a much larger box than a sealed one. Depending on what you want exactly, if it be from a ported box, whether you want spl or sq, building a box dependent on the Thiele-Small parameters and then tuning your box to the resonant frequency of you vehicle (spl) or lower (sq) will yield the best results and be much more fun. You could try to figure out what that Q-Logic box is tuned at and go from there. Remember it's the tuning with the subs IN the box. I wonder what the suitability check would be for that sub. To know if the subs would be more suited to a sealed or ported enclosure just find EBP. With a versatile sub like that it'll probably be closer to 50 (1-50 more suited to sealed, 50-100 more suited to a ported enclosure). Since I don't know what size, or even what year (model) your subs are I can't tell you what it is. But just take the Fs (resonant frequency) and divide it by the Qes (electrical Q) to get Efficiency Bandwidth Product (if you're worried about the quality side of it). Well, you're already on here, you can learn a lot here and I'll just say everyone is always much happier with a custom box.

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I've finally turned my obsession into my profession

fix-8x wrote:

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I would think sq wise the subs would be slightly more responsive but it they would still drop down low in that smaller box. If you want clarity (very quick response) than go sealed but between those two, again the smaller box. I would think the bigger box would be louder. Force? Pressure wise? Again I think the bigger one would be louder. Expand on your "etc.". What kind of music do you listen to? Comp.? Daily driver? What is the vehicle? Are the ports the same size on these different sized boxes? Why did you choose to go ported???
Now when you say the recommended box size was 1.5 - 3.5 is this ported or sealed. Ported is always a much larger box than a sealed one. Depending on what you want exactly, if it be from a ported box, whether you want spl or sq, building a box dependent on the Thiele-Small parameters and then tuning your box to the resonant frequency of you vehicle (spl) or lower (sq) will yield the best results and be much more fun. You could try to figure out what that Q-Logic box is tuned at and go from there. Remember it's the tuning with the subs IN the box. I wonder what the suitability check would be for that sub. To know if the subs would be more suited to a sealed or ported enclosure just find EBP. With a versatile sub like that it'll probably be closer to 50 (1-50 more suited to sealed, 50-100 more suited to a ported enclosure). Since I don't know what size, or even what year (model) your subs are I can't tell you what it is. But just take the Fs (resonant frequency) and divide it by the Qes (electrical Q) to get Efficiency Bandwidth Product (if you're worried about the quality side of it). Well, you're already on here, you can learn a lot here and I'll just say everyone is always much happier with a custom box.

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I listen to a wide variety of music, but i do really enjoy listening to a lot of rap and music with large bass notes.  I crave that "owe that hurts my chest and throat feeling" haha.  I drive a 1992 Nissan 240sx, it is a daily driver, and soon to be track car as well, so i want a box so that it can easily be removed for drift comps. but anyways. 

Ported because it is louder and stronger.  Right?

The recommended size is 1.5 - 3.5ft^3 for a Ported box.  A seal box volume is from 1.4-2.0ft^3

The subs are at this link here

https://www.alpine-usa.com/US-en/products/product.php?model=SWR-1242D

The Box links are here.

The 2.5ft^3

https://www.qlogicenclosures.com/c-4620-qlh-12512ds.aspx

The 3.5ft^3 box

https://www.qlogicenclosures.com/c-4621-qlh-17512ds.aspx

thanks

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Tyler B.

Ported boxes give you the ability to run a little less power to subs making them a bit more efficient. If you want to run them at rms or above I would do sealed box. More rigid drum but still good low end.
Ported is kinda sloppy in my opinion. Bandpass is slightly different. It is kinda a combination of sealed and ported. I have head a few of these and they shake you pretty good. It depends if the woofer will work in that type enclosure. I think sealed for more sq and ported for bass end with less power. Thats why you tune the port to a specific frequency.

I think to do this quickly you will still be happy if you get the bigger box (and make sure it will fit in your application) and then seal it up nice, especially around those terminal cups and edges. Not the port of course. Have you checked out the PDX-1000.1? That'll hit 'em nice and hard if you're looking to stick with Alpine or even two PDXs if you'll be careful. Post back with what it meters and what amps you ended up doing, of course what box also. Any more questions, post back.

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I've finally turned my obsession into my profession