Port length exceeding area?

[Jake321]

So I'm about to order dual 4" ports but to tune to 33Hz I'd have to increase the length from 9" single to 19" dual.

Also was thinking of Tuning it to the FS of Sub 29Hz. (30" Port).

When does the length of the port begin to hit a exceeding length?

Subwoofer:
DD712 1Ohm

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[Jake321]

So I'm about to order dual 4" ports but to tune to 33Hz I'd have to increase the length from 9" single to 19" dual.

Also was thinking of Tuning it to the FS of Sub 29Hz. (30" Port).

When does the length of the port begin to hit a unreasonable length?

Subwoofer:
DD712 1Ohm

 

[Jimi77 5,000+ posts]

So I'm about to order dual 4" ports but to tune to 33Hz I'd have to increase the length from 9" single to 19" dual.

Also was thinking of Tuning it to the FS of Sub 29Hz. (30" Port).

When does the length of the port begin to hit a exceeding length?

Subwoofer:
DD712 1Ohm

When you can't fit the port in the space you're using.

 

[winkychevelle 10+ year member]

My newest box design has a 62inch port 28hz chamber and a 19inch port 55hz chamber so there isn't any length restriction. Port length is relative to enclosure size and port area.

And tuning to fs won't hurt but I'd tune towards your listening preference or cabin gain first

 

[Jake321]

My newest box design has a 62inch port 28hz chamber and a 19inch port 55hz chamber so there isn't any length restriction. Port length is relative to enclosure size and port area.

And tuning to fs won't hurt but I'd tune towards your listening preference or cabin gain first

That's eye opening! Thanks!

 

[Jake321]

Ok proof your advice wasn't a waste of time.

I went out and bought a 6" PVC Pipe. $55.

Cut it at 34" 2.6 Cubes after Port displacement.

FS of 712: 28.26.
Tuning to 28HZ.

 

[winkychevelle 10+ year member]

Long ports are nothing new when you need port area to keep down port noise. Benifits to slot ports is the ease of turning the port. You can do the same with pipe ports too

 

[Ridinhi 5,000+ posts]

Long ports are nothing new when you need port area to keep down port noise. Benifits to slot ports is the ease of turning the port. You can do the same with pipe ports tooView attachment 44638View attachment 44639

Looking foward to seeing this!

 

[winkychevelle 10+ year member]

Looking foward to seeing this!

Me too I think I'm gonna try sketchup over the holidays to make the design look better and maybe build it too. Money is tighter than I'd like and I'm putting other things first so it's a lot of planning right now.

 

[Ridinhi 5,000+ posts]

Me too I think I'm gonna try sketchup over the holidays to make the design look better and maybe build it too. Money is tighter than I'd like and I'm putting other things first so it's a lot of planning right now.

Totally understand man. Same here.

 

[winkychevelle 10+ year member]

Totally understand man. Same here.

Knowing me I'm probably gonna pick the subs up and a few sheets of wood earlier than I should but I want to spend the money and buy all the right tools so this build comes out to be the best I can do. My tool/hardware list alone comes out to about $500

 

[Ridinhi 5,000+ posts]

And this build will be for the nvx subs? I had eyed those subs a few times myself

 

[winkychevelle 10+ year member]

And this build will be for the nvx subs? I had eyed those subs a few times myself

Yea that's the plan. I need to remeasure my cabin gain but the box is quite flat 30-65hz my mids are playing down the 50hz now and I think I'm gonna go 3way with stereo integrity tm8s, SB Acoustics SB10PGC21-4, m25 mkii

I might end up trying the 8inch silverflutes first. Gonna be the first time I cut up my door panels for speakers so it might be a $1000 mistake. Damn door panels are $500 each.

Doing the 3inch on the dash makes me worry though. It's gonna make my midrange so much louder and might pull my sound stage too high. Idk the dsp should help with alot of my worry

 

[Ridinhi 5,000+ posts]

Yea that's the plan. I need to remeasure my cabin gain but the box is quite flat 30-65hz my mids are playing down the 50hz now and I think I'm gonna go 3way with stereo integrity tm8s, SB Acoustics SB10PGC21-4, m25 mkii

I might end up trying the 8inch silverflutes first. Gonna be the first time I cut up my door panels for speakers so it might be a $1000 mistake. Damn door panels are $500 each.

Doing the 3inch on the dash makes me worry though. It's gonna make my midrange so much louder and might pull my sound stage too high. Idk the dsp should help with alot of my worry

I’m definitely tuned in!

 

[Jake321]

Long ports are nothing new when you need port area to keep down port noise. Benifits to slot ports is the ease of turning the port. You can do the same with pipe ports tooView attachment 44638View attachment 44639

That's how! Got it