Build your own 2x12" TH (The Kraken 212 TH) - diyAudio
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Old 8th February 2010, 05:55 PM   #1
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Default Build your own 2x12" TH (The Kraken 212 TH)

Drivers can handle 350W RMS/piece (700W total) 14 mm X-Max
Model JBL GTO1214
Net volume is 500 liter.


Simulated for corner placement, 2,83V, driers in parallell. 135 dB @ 20 Hz.

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Braced with 12 mm plywood/MDF, as image below

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Internal dimensions, materialthickness 22 mm

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Build your own and tell me if it works

Last edited by Petter Persson; 1st May 2012 at 01:30 PM.
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Old 9th February 2010, 02:33 AM   #2
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you could probably flatten out the higher spl response by flaring out the mouth, but then you would not have a nice rectangle dimension. i bet the distortion would increase as volume does with that port shape as well.

of course i am a big fan of large curved flared "tuba" ports for subs. they sound smoother too.


what ideas do you have for lining the first couple of meters in that design?
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Old 9th February 2010, 03:07 AM   #3
FlipC is offline FlipC  United States
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Tx for sharing.
Interesting layout.

Side note -
I haven't come across a TH build where the high end is as simulated/ Always less.

Also post the HR data.
To lazy to re-figure that out.
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Old 9th February 2010, 07:12 AM   #4
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Quote:
you could probably flatten out the higher spl response by flaring out the mouth,
No, just increase the high freq. sensitivity on cost of low end sensitivity.

Quote:
but then you would not have a nice rectangle dimension.
Yes, thats true. This box design is made to be as flat as possible and to just fit on a standard 120x240 cm sheet to maximise acoustic output compared to the material used.

Quote:
i bet the distortion would increase as volume does with that port shape as well.
Why? Plese explain. At these waewlengts, i can't see why...

Quote:
of course i am a big fan of large curved flared "tuba" ports for subs. they sound smoother too.
Smoother tha all tapped horns...A bit too much generalization maybe...

Quote:
what ideas do you have for lining the first couple of meters in that design?
Since I have not built them, I don't know. One has to study the measured freq. response and listen too determaine such things is my experience.



Quote:
Tx for sharing.
Interesting layout.
Welcome and thanx

Quote:
Side note -
I haven't come across a TH build where the high end is as simulated/ Always less.
Well, that depends on the folding. This folding will make the horn measure
quite the same as the simulation. For a single fold, the first dip will be filled
in. for example in my own tapped horns. 2 pi measurement and simulation.
The high end seems pretty intact...Levels are normilized. No Smoothing applied,
measured 2.5 meters from the mouth on axis, ground plane.

Click the image to open in full size.

Quote:
Also post the HR data.
To lazy to re-figure that out.
Naa...too lazy do that, if it is of eaugh intrest, you just have to do some back engineering

Last edited by Petter Persson; 9th February 2010 at 07:22 AM.
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Old 9th February 2010, 08:58 AM   #5
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http://www.jbl.com/resources/Brands/.../GTO1214TD.pdf
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Old 10th February 2010, 12:24 AM   #6
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Quote:
Originally Posted by Petter Persson View Post


Why? Plese explain. At these waewlengts, i can't see why...



Smoother tha all tapped horns...A bit too much generalization maybe...

i meant flared sub "horns" not ported tubes. my bad.

well in my experiences building subs with wider more flared mouths produced less distorted and more musical sounding compared to just the smaller or square opening at higher volumes.
i would have to guess it might have to do with moving air maybe.


i could be splitting hairs as most sound that low is more of a thud/boom/puff kind of sound and not musical.
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Old 10th February 2010, 06:29 AM   #7
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Aha, okej, then I understand better. A larger mouth creates a better coupling
between the air in the horn and the surrounding air and reduces air speeed in
the mouth region. The mouth area in this horn is 1625 cm2, about three times
the SD, so it's pretty large any way...As you mentioned, a larger mouth would
not fit in the desiered outer dimensions.
A larger mouth also lowers the q at the res. freq. and then lowers the group
delay, giving a more tight "musical" sound on cost of efficiency/box volume though.
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Old 10th February 2010, 01:44 PM   #8
tb46 is offline tb46  United States
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Hi Petter,

The SD area is 2x 511cm^2, isn't it?

Regards,
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File Type: jpg Hornresp_Input_guess.jpg (41.2 KB, 569 views)
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Old 10th February 2010, 02:01 PM   #9
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Correct! So, 3 x Sd would = 3,066cm^2.
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Old 10th February 2010, 03:24 PM   #10
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Nice job Oliver The only difference is about 0,5 dB around the 70-Hz-peak and
since this still only is a simulation, the differences are of academic value...
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