why JL subwoofers are sealed ? WINISD demands ported!!! - diyAudio
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Old 26th September 2011, 08:40 PM   #1
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Default why JL subwoofers are sealed ? WINISD demands ported!!!

Image 1.jpg

Image 2.jpg

Image 3.jpg

Image 4.jpg

well another of my confused questions. Lets solve the mystery

woking around with JL 13W7 subwoofer i found some thing amazing.

4 designs were condiered.
sealed, vented, passive , sealed with LT figure 1 (transfer function plot)


clolours
yello=sealed
Orange=LT transform
Grey=vented
Pink PR


the vented c4/chebyschev showed maximum output , deepeset with a little hump at 20 hz, the closest was passive with 21 inch exodus PR with 1000 g mass. next was LT transform having good transfer function but the maximum SPL remained same as that of sealed figure 2.

The box size and tuning frequnecy is given in Figure 3.

The group delay is given in Figure 4.

Such a large disparity in SPL out leaves me wondering why JL decides to go sealed ??????????

What route diy should take ???
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Old 26th September 2011, 09:03 PM   #2
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A quick follow up. Figure 7 is SPL at 1000 W input .

Image 7.jpg

LT transforms seems good on the output SPL at 1000 Watss

BUT The cone excursion however shows that LTZ is not an option the excursion skyrockets below 50 Hz . Figure 8

Image 8.jpg
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Old 26th September 2011, 09:30 PM   #3
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Perhaps they just didn't like what a multi-resonant box sounds like, precise calculation of parameters not withstanding?*

B.

* Do you believe your model encompasses all that can be said about the sound of a speaker? Most of what matters? Or, um, not a bad starting point but no more than that? Ptolemy thought he had the heavens figured out pretty good and to a crude approximation, he did.
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Last edited by bentoronto; 26th September 2011 at 09:34 PM.
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Old 26th September 2011, 10:20 PM   #4
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its way off the common sense.....paramaters notwithstanding......agreed the sound cannot be defined in technical terms...but its the parameters which are the driver design in the first place......still sealed makes no sense ...
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Old 26th September 2011, 10:58 PM   #5
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logistics of shipping huge, heavy boxes!?
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Old 26th September 2011, 11:19 PM   #6
doug20 is offline doug20  United States
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You have to take WinISD suggested box choice with a grain of salt!!!

This means who cares if WinISD suggests ported over sealed. There are many, many other factors that go into a design and if you really look at the JL driver you will understand it will perform very, very well in either alignment.

Honestly, I have never even cared with WinISD suggested when I model any driver. I choose the alignment that fits the project and I see if the driver works in that alignment.

Quote:
Such a large disparity in SPL out leaves me wondering why JL decides to go sealed ??????????
For the size of the box, its still one of the most impressed subwoofer designs out there I have seen. Ikka's measurements on HTS show it holds its own against many, many monster designs.

btw, in any single box design ported WILL ALWAYS have more output then its sealed cousin!! Its not an apples to oranges comparison either since alignments are usually used for different applications.


Quote:
What route diy should take ???
The route that fits your objectives/boundaries/constraints the best!!

Last edited by doug20; 26th September 2011 at 11:25 PM.
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Old 26th September 2011, 11:24 PM   #7
sreten is offline sreten  United Kingdom
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Hi,

Vented PR boxes and/or vented boxes are typically twice the size of sealed.
They will always have max SPL advantages over sealed but at very low
tunings this is barely a real advantage unless you like organ music.

If you don't need the max SPL of vented/PR, sealed with possibly some
bass boost makes a lot of sense, half the size and with better transients.

rgds, sreten.

Note maximum SPLs generally have nothing to do with frequency response.
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Old 26th September 2011, 11:26 PM   #8
doug20 is offline doug20  United States
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Quote:
but at very low
tunings this is barely a real advantage unless you like organ music.
Or Home Theater. Which pretty much dominates the market now.
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Old 27th September 2011, 01:58 PM   #9
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that means that Jl line is for music consideration and not HT.????

my question is out of curoisity that how could the sealed design be that good in output as widely reported without any LT equilization. while being advertised mostly for HT why it is selaed which is usually for music subs. i would like a comparision with wilson audio watch dog which is passive around 6000 usd using one 12 inch driver and twice the cabinet size with vented design but reported tooo musical ???
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Old 27th September 2011, 02:05 PM   #10
CBRworm is offline CBRworm  United States
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I thought the 13w7, and it's relatives were made for car audio?
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