Slotted "maze" ports

[Ronny 10+ year member]

You could try placing the driver on one extreme of the enclosure and doing an S-port.. Or even add another wall to make it an.. Actually I don't know what that would be called. A winding tunnel like port

 

[Brian Owens 10+ year member]

I normally do something like this. . .

 

[RAM_Designs 5,000+ posts]

^^^that looks like a lot of work.

 

[soldiermedic 10+ year member]

Yeah. But he's the only one that has given me anything close to a picture of what I am trying to get an idea about.

 

[RAM_Designs 5,000+ posts]

 

[audio_phill 10+ year member]

Wow..so many responses...yet so little help. Anyway, I am planning to do a box for a single 10" sub tuned to 26hz for a flat response from 30hz and up. Box size will be 1.75cu. Low pass will be set at 125hz. Also, I have a question as to whether winISD calculates displacement for the sub and port or do I have to do that myself.

WinISD does not account for any displacement, volume given is net, you have to figure out port displacement and add it to the net volume. The Box Shape/Size option uses golden ratio FYI. heres one way I fold my ports. 32Hz in 1 cube net. 57.75" of port compound folds .

 

[audio_phill 10+ year member]

Finished Raw Box. 1/64" tolerances, $90. lol.

 

[audio_phill 10+ year member]

Heres another, 1.4 @ 34Hz with 36"sq port, ~53.25" long port. $55

 

[Brian Owens 10+ year member]

The golden ratio does not matter for a subwoofer unless you have a length over ~5.5 ft long inside the box. . .

I am curious, why not round over or 45 the inside edges of the turns on those ports? It would allow you to have a larger 45 on the outside while maintaining the required port width.

Brian

 

[soldiermedic 10+ year member]

Awesome. Thanks for all the visuals. I would have missed putting the blocks to ensure consistency of the port width throughout had I not seen them in yours. I also see that I need to increase the planned depth of the box for displacement of the sub as well as the port walls (which was the only thing I accounted for).

 

[audio_phill 10+ year member]

The golden ratio does not matter for a subwoofer unless you have a length over ~5.5 ft long inside the box. . .
I am curious, why not round over or 45 the inside edges of the turns on those ports? It would allow you to have a larger 45 on the outside while maintaining the required port width.

Brian

Golden ratio effects the sound and efficiency of the enclosure as well as increase upper freq roll off and lessen output deviation. These boxes were slap together few hour jobs, and as low as the Vas was on the driver, the vent mach was so low it wouldn't have benefited in any way since 45's don't remove standing waves. As for maintaining proper port width, 45'ed corners dont allow for nominal width anyway, only nominal radius (1/4 turn corners/edges do,) lol. geometry people, lol.

 

[soldiermedic 10+ year member]

Oh yeah...I forgot that I am a little slow when it comes to that. Speaking of geometry, how do I calculate displacement for my port and speaker? I figure that I have to get the speaker mounting depth measurements, but what of the port?

 

[soldiermedic 10+ year member]

Also, is there a reason to offset the vent for a box mo less than 3" from the side of the box? Just a suggestion that I wanna check.

 

[audio_phill 10+ year member]

Oh yeah...I forgot that I am a little slow when it comes to that. Speaking of geometry, how do I calculate displacement for my port and speaker? I figure that I have to get the speaker mounting depth measurements, but what of the port?

port displacement is (port width + board thickness) x height x length, divided by 1728

sub displacement can be found by using the sub displacement calculator in WinISD Pro Alpha and a measuring tape.

Also, is there a reason to offset the vent for a box mo less than 3" from the side of the box? Just a suggestion that I wanna check.

No need to offset the port. Ports like in the boxes above are perfectly fine. Design it to have a vent mach .05 - .03 and you're good to go.

 

[soldiermedic 10+ year member]

port displacement is (port width + board thickness) x height x length, divided by 1728sub displacement can be found by using the sub displacement calculator in WinISD Pro Alpha and a measuring tape.

No need to offset the port. Ports like in the boxes above are perfectly fine. Design it to have a vent mach .05 - .03 and you're good to go.

Ouch...a vent mach at that range is difficult right now...is 0.08 ok?