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Discussion Starter · #1 ·
I might be moving soon so I am trying to make my subs easier to transport.

I was thinking about making 2 sub/stands for the L/R speakers using 3x1260w (can't find specs for 1262w or would use that) in 7-9cu tuned to 15hz and hpf at 11-12hz

I am having a hard time figuring out the slot port on winisd.

Goal is to have one fire right, one fire left and one fire forward.
To keep them transportable:
Total height 2ft or less.
Depth no more than 16 inches (18 max)

Might build a 3rd for nearfield also.

Can anyone help with how the figure out the port?
 

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Discussion Starter · #3 ·

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That helps trying the 1262 but I can't figure out the ports.

It looks like winisd doesn't let you get anything, it wants you to use tiny ports that don't make sense
Huh?

I just modeled the 1262 with the parameters from that link, and it's showing me that 3 of those drivers in an 8ft^3 enclosure looks better SPL wise when it's tuned higher, it's a pretty quick slope when trying to tune it low and keep the excursion within it's limits.
Still working on that, but if the parameters were correct(and they should be close, it's an Infinity PDF) the drivers reach excursion fairly quick with 330W ea(says 300w RMS 1200pk).

I used 1000w as a signal, what do you plan on running for power?
 

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Discussion Starter · #9 ·
Huh?

I just modeled the 1262 with the parameters from that link, and it's showing me that 3 of those drivers in an 8ft^3 enclosure looks better SPL wise when it's tuned higher, it's a pretty quick slope when trying to tune it low and keep the excursion within it's limits.
Still working on that, but if the parameters were correct(and they should be close, it's an Infinity PDF) the drivers reach excursion fairly quick with 330W ea(says 300w RMS 1200pk).

I used 1000w as a signal, what do you plan on running for power?
What good is SPL without extension?

I'd never tune a sub over 15hz. We don't need single digits but I'm not giving up 13-20...no way
 

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What good is SPL without extension?
I'd never tune a sub over 15hz. We don't need single digits but I'm not giving up 13-20...no way
If that's the case you'd best figure on 7-9cu ft per driver. Hoffman's Iron Law is not negotiable.
 

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thanks - will try. I am just not understanding how the larger you make the port the longer it has to be.
To keep the air speed under 30 it wants a port thats around 50in long
That's the balancing act. Make the port small diameter/width and it can be shorter, but you're more likely to run into chuffing. Make it larger diameter, and it has to be longer, and takes up more space in the box, and if it's too long, the port resonances can be issues.

Also, be sure to set a high pass filter in WinISD. That will control driver excursion below the tuning frequency, and often knocks the port air velocity down a notch too, which always helps.
 

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Discussion Starter · #13 ·
If that's the case you'd best figure on 7-9cu ft per driver. Hoffman's Iron Law is not negotiable.
Understood... But I plan on building 3 of them eventually...

With 1 right behind the seat and the other 2 up front, reference level at 15hz should be possible AND I like that it acts almost like an LLT in that it rolls off like a sealed but slower.

I sort of like this design
 

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Discussion Starter · #16 ·
If you don't want huge boxes id tune to 18 or 20. I think it will give a better overall result.
I'd go sealed first.

My design idea was long roll off and low tune even if it meant losing spl. It looks like a hybrid sealed/ported almost. Get some of the limits from each and also benefits.

Maybe can cut the drivers down to 2.
 

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Here's what I get with 1100w at 1m
What High Pass Filter/Cutoff are you using there, and what does the Excursion look like with that filtering scenario you are showing at 1100W?
I can get 3x1262 to look similar, but 1100 is stretching the limits with excursion, and I'm not seeing 110DB at 15hz

EDIT: My modeling is done using 3x1262 in an 8ft^3 box- tuned to 15
 

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Keep in mind that those dimensions give you a little over 6 CF internal, and the port could easily take up 1 CF, plus more from bracing and drivers.

Also, looks like you might need to adjust the HPF to keep excursion under better control. Something like EOT could put some pain on these drivers.
 
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