help with a new box

[bbeljefe]

You have enough space to build a dual chamber bass reflex box for that sub and still maintain your 17" overall height. And if you've never run a ported enclosure in that vehicle, a dcbr will blow your effing mind with how hard it hits...

Three cubes total net volume. Divide that into two portions of 2/3 and 1/3.

2/3 portion is 2 cubes.... 1/3 portion is 1 cube.

Vents are 4" round by 20.5" long. Original box tuning is 31Hz, which presents a pretty flat frequency response from that driver.

Sub and two vents go into the 2/3 volume with one vent exiting the cabinet and the other venting into the 1/3 portion. Third vent is in the 1/3 section exiting the cabinet.

This leaves you with:

2/3 cabinet tuned to ~27 Hz

1/3 cabinet tuned to ~38 Hz

Load both vents off the back wall and load the sub off the ceiling or back wall. Ergo, ports back, sub either up or back.

Finish box, put plastic on any seats a female will be sitting on and crank up teh volumez.

[goldeneye4564]

You have enough space to build a dual chamber bass reflex box for that sub and still maintain your 17" overall height. And if you've never run a ported enclosure in that vehicle, a dcbr will blow your effing mind with how hard it hits...

Three cubes total net volume. Divide that into two portions of 2/3 and 1/3.

2/3 portion is 2 cubes.... 1/3 portion is 1 cube.

Vents are 4" round by 20.5" long. Original box tuning is 31Hz, which presents a pretty flat frequency response from that driver.

Sub and two vents go into the 2/3 volume with one vent exiting the cabinet and the other venting into the 1/3 portion. Third vent is in the 1/3 section exiting the cabinet.

This leaves you with:

2/3 cabinet tuned to ~27 Hz

1/3 cabinet tuned to ~38 Hz

Load both vents off the back wall and load the sub off the ceiling or back wall. Ergo, ports back, sub either up or back.

Finish box, put plastic on any seats a female will be sitting on and crank up teh volumez.

my mind is blown

[1two3]

You have enough space to build a dual chamber bass reflex box for that sub and still maintain your 17" overall height. And if you've never run a ported enclosure in that vehicle, a dcbr will blow your effing mind with how hard it hits...

Three cubes total net volume. Divide that into two portions of 2/3 and 1/3.

2/3 portion is 2 cubes.... 1/3 portion is 1 cube.

Vents are 4" round by 20.5" long. Original box tuning is 31Hz, which presents a pretty flat frequency response from that driver.

Sub and two vents go into the 2/3 volume with one vent exiting the cabinet and the other venting into the 1/3 portion. Third vent is in the 1/3 section exiting the cabinet.

This leaves you with:

2/3 cabinet tuned to ~27 Hz

1/3 cabinet tuned to ~38 Hz

Load both vents off the back wall and load the sub off the ceiling or back wall. Ergo, ports back, sub either up or back.

Finish box, put plastic on any seats a female will be sitting on and crank up teh volumez.

sounds like an interesting box design...definatly new to me

with that being said i have a few question abouit that design. im not so much woried about how hard it hits my main goal here is sq. now i know im not going 100% sq here but i do still want the sub to have acurate bass notes, have a fairly flat responce, and a good group delay.

also with that design is it possible/worth getting 4" flared podrts

im not gonna lie i wouldnt mind having the option of turning it way up but its still not my main goal.

is this the kind of design ur talking about...the bigger chamber being the 2/3s and the smaller the 1/3/?

[bbeljefe]

sounds like an interesting box design...definatly new to me

with that being said i have a few question abouit that design. im not so much woried about how hard it hits my main goal here is sq. now i know im not going 100% sq here but i do still want the sub to have acurate bass notes, have a fairly flat responce, and a good group delay.

also with that design is it possible/worth getting 4" flared podrts

im not gonna lie i wouldnt mind having the option of turning it way up but its still not my main goal.

is this the kind of design ur talking about...the bigger chamber being the 2/3s and the smaller the 1/3/?

Yep, that's it. And for sure, aero ports would be better. It will be an SQ box as much as it's an SPL box. It's kinda like a cross between a parallel 6th order and a ported enclosures. You don't get the acoustical gains you do from a 6th but you will get gains and the box will still play a wide frequency range relatively flat.

[1two3]

Yep, that's it. And for sure, aero ports would be better. It will be an SQ box as much as it's an SPL box. It's kinda like a cross between a parallel 6th order and a ported enclosures. You don't get the acoustical gains you do from a 6th but you will get gains and the box will still play a wide frequency range relatively flat.

OK and how would it sound compared to sealed? I can assume much louder but sq wise?

Having flared ports would the total length of the port include the flare or no?

I'm also worried about the box size. Recommended box size for ported is in the 4 cube range. Aren't these box sizes all trail and error? Do u have any experience with this style box with a 15?

[bbeljefe]

Yep, that's it. And for sure, aero ports would be better. It will be an SQ box as much as it's an SPL box. It's kinda like a cross between a parallel 6th order and a ported enclosures. You don't get the acoustical gains you do from a 6th but you will get gains and the box will still play a wide frequency range relatively flat.

OK and how would it sound compared to sealed? I can assume much louder but sq wise?

Having flared ports would the total length of the port include the flare or no?

I'm also worried about the box size. Recommended box size for ported is in the 4 cube range. Aren't these box sizes all trail and error? Do u have any experience with this style box with a 15?

A well built well designed ported enclosure will provide plenty of SQ. Flare ports are measured a bit differently but the easiest thing to do is use Precision Port's calculator.

As for the volume, just use the volume recommended by the manufacturer if you're unable to model it in a program. Use the larger recommendation and make the alterations to the design as mentioned above. And no, I've not built one for a 15 but that's irrelevant.... the only difference is hole size and box volume, as the alignment will work well with any size woofer.

As for the trial and error part, I suppose any box would be so if the driver hadn't been used in that alignment before. But if you know the driver's parameters and it will work well in a conventional ported box, it'll work well in a dcbr. Your driver has an EBP of 69, which lends it well to ported boxes so it'll do even better in a dcbr.

[1two3]

A well built well designed ported enclosure will provide plenty of SQ. Flare ports are measured a bit differently but the easiest thing to do is use Precision Port's calculator.

As for the volume, just use the volume recommended by the manufacturer if you're unable to model it in a program. Use the larger recommendation and make the alterations to the design as mentioned above. And no, I've not built one for a 15 but that's irrelevant.... the only difference is hole size and box volume, as the alignment will work well with any size woofer.

As for the trial and error part, I suppose any box would be so if the driver hadn't been used in that alignment before. But if you know the driver's parameters and it will work well in a conventional ported box, it'll work well in a dcbr. Your driver has an EBP of 69, which lends it well to ported boxes so it'll do even better in a dcbr.

my main concern here is the box volume. i dont want to damage the suspension or unload the sub. being in one chamber thats 2 cubes and the other being 1 cube...i just dont understand how that would be big enough. (remmber i have little to none experience with ported boxes)

i want to design this box myself but i do have a few questions.

1. whatever area of the aeroports are inside the chamber...that is subtracted from the box volume? (looking at the diagram the blue is chamber 1 volume or 2 cubes)

2. Looking at this diagram agian, do i subtract the port going between the two boxes from the volumes aswell?

3. Is there a minimum distance from the ports to the back walls?

[bbeljefe]

A well built well designed ported enclosure will provide plenty of SQ. Flare ports are measured a bit differently but the easiest thing to do is use Precision Port's calculator.

As for the volume, just use the volume recommended by the manufacturer if you're unable to model it in a program. Use the larger recommendation and make the alterations to the design as mentioned above. And no, I've not built one for a 15 but that's irrelevant.... the only difference is hole size and box volume, as the alignment will work well with any size woofer.

As for the trial and error part, I suppose any box would be so if the driver hadn't been used in that alignment before. But if you know the driver's parameters and it will work well in a conventional ported box, it'll work well in a dcbr. Your driver has an EBP of 69, which lends it well to ported boxes so it'll do even better in a dcbr.

my main concern here is the box volume. i dont want to damage the suspension or unload the sub. being in one chamber thats 2 cubes and the other being 1 cube...i just dont understand how that would be big enough. (remmber i have little to none experience with ported boxes)

i want to design this box myself but i do have a few questions.

1. whatever area of the aeroports are inside the chamber...that is subtracted from the box volume? (looking at the diagram the blue is chamber 1 volume or 2 cubes)

2. Looking at this diagram agian, do i subtract the port going between the two boxes from the volumes aswell?

3. Is there a minimum distance from the ports to the back walls?

You can read more on this design here. In simple terms, the driver doesn't "see" the second chamber as anything other than part of the total volume it is in. Moreover, it isn't small boxes that woofers unload in, it's poorly designed boxes with either two or more drivers or, where the woofer is driven hard below Fb. With this alignment, Fb of the larger chamber is well below typical car audio tuning, so it's safer at low frequencies than most. And because the woofer sees the second chamber as just more air space, it's acoustical suspension is no different than if it were one large box.

As for port volumes, they need to be accounted for in the total Vb and you need that net total including them, so add their volumes to the box volume you need. For the interchamber port, either put it half way into each chamber and divide that between them or put it all the way in one or the other and add that volume to the volume needed for that chamber.

Spacing between port ends and cabinet walls should always be one port width or more, regardless the particular style of ported box. For slot ports, I maintain double the narrow dimension.

[1two3]

You can read more on this design here. In simple terms, the driver doesn't "see" the second chamber as anything other than part of the total volume it is in. Moreover, it isn't small boxes that woofers unload in, it's poorly designed boxes with either two or more drivers or, where the woofer is driven hard below Fb. With this alignment, Fb of the larger chamber is well below typical car audio tuning, so it's safer at low frequencies than most. And because the woofer sees the second chamber as just more air space, it's acoustical suspension is no different than if it were one large box.

As for port volumes, they need to be accounted for in the total Vb and you need that net total including them, so add their volumes to the box volume you need. For the interchamber port, either put it half way into each chamber and divide that between them or put it all the way in one or the other and add that volume to the volume needed for that chamber.

Spacing between port ends and cabinet walls should always be one port width or more, regardless the particular style of ported box. For slot ports, I maintain double the narrow dimension.

ok and just clarifying why u used 3 cubes? just to keep the box as small as possible and keep the dimentions as easy as possible?

could i use the optimal dimentions? wouldnt it even be better that way?

[bbeljefe]

You can read more on this design here. In simple terms, the driver doesn't "see" the second chamber as anything other than part of the total volume it is in. Moreover, it isn't small boxes that woofers unload in, it's poorly designed boxes with either two or more drivers or, where the woofer is driven hard below Fb. With this alignment, Fb of the larger chamber is well below typical car audio tuning, so it's safer at low frequencies than most. And because the woofer sees the second chamber as just more air space, it's acoustical suspension is no different than if it were one large box.

As for port volumes, they need to be accounted for in the total Vb and you need that net total including them, so add their volumes to the box volume you need. For the interchamber port, either put it half way into each chamber and divide that between them or put it all the way in one or the other and add that volume to the volume needed for that chamber.

Spacing between port ends and cabinet walls should always be one port width or more, regardless the particular style of ported box. For slot ports, I maintain double the narrow dimension.

ok and just clarifying why u used 3 cubes? just to keep the box as small as possible and keep the dimentions as easy as possible?

could i use the optimal dimentions? wouldnt it even be better that way?

Honestly, I don't remember at this point why I picked three cubes. I would think because of the space you have available but I'm too lazy to read the thread over again, lol.

But yeah, the place to start is with the ideal ported box and then use that volume and port size for the dcbr.