Build your own 2x12" TH (The Kraken 212 TH) - Page 10 - diyAudio
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Old 4th November 2011, 12:20 AM   #91
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Has anyone looked at Digital Designs woofers? I use them regularly for nightclub boxes and have a killer t line dual 8" that plays to 30hz in my car. Wonderful, nearly unkillable drivers. DD Audio They make me some custom versions of the 1500 series 12" driver that suit my needs.
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Old 4th November 2011, 02:07 AM   #92
18Hurts is offline 18Hurts  United States
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I took a look at the very sparse spec sheets on the DD woofers,

The JBLs have a lower resonant frequency at 28Hz VS the DD 30.3Hz which can cause issues. Also the sensitivity is 5dB lower at 85dB VS 90dB of the JBL (at 2.83 volts) Since DD did not put the sensitivity spec at one watt, I am assuming it is 2.83V. It won't go as low or be as loud as the JBL at the same power input levels.

The Kraken is tuned at 18Hz which is very low for a DD to be tuned, I'm sure it can withstand being pushed that far down but the cone travel will be used up trying to get the same SPL as the JBLs.

Another option to entertain is what would a JBL GTO 1514 do with the design as a single woofer. It has the same output as two 1214's and the 15 incher has a Fs of 25.1 Hz. Could the design of the Kraken be modified to run a 16 Hz tuning with a single 15" JBL? It would have to be wider which would help with stability but I'm worried about compression on the cone. The 15" version looks spec wise about the same as the 12" with the same voice coil diameter so the compression ratio might need to be dropped down.

One of my games with Horn Response is to play with the Kraken design--if I'm going to modify something, knowing that it works at a very high level is a great place to start. Model a single 12" and a single 15" and calculate size/weight and see if the 15" could handle a 17 or 16 Hz tuning. I was not smart enough to cut wood before the cold weather came so it's a good excuse to become proficient with Horn Response while the cold winds blow and freeze my wood working area.
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Old 5th November 2011, 11:31 AM   #93
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Quote:
Originally Posted by Nathanshort View Post
Has anyone looked at Digital Designs woofers? I use them regularly for nightclub boxes and have a killer t line dual 8" that plays to 30hz in my car. Wonderful, nearly unkillable drivers. DD Audio They make me some custom versions of the 1500 series 12" driver that suit my needs.
I had a look at their website and the qts of the drivers are far to high for horn
use. The 9500-series would work fine, but they are kind of pricy...
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Old 5th November 2011, 11:51 AM   #94
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Spuddy, your build and word has encouraged me to develop the "Kraken 210"
and the "Kraken 112" as well. The new drawing of your "Kraken 212" will be
uploaded next week. Unfortunatilly, the space inside the throat makes it
impossible to fit the 10"-drivers in push pull configuration. On the other hand,
compared to Kraken 212, there is a significant space save (good for family
living rooms...), se images below.


The Kraken 112

Click the image to open in full size.

The inner width and the outlet hole is 320mm wide/high. Material thickness is
22mm. I will recalculate this later on to inches and also to 3/4" but this is a
good start. The driver is the same JBL GTO 1214 as in Kraken 212. The driver
shall be placed magnet out.

Click the image to open in full size.

The length of each board is set to the maximum length, due to the angle.


Click the image to open in full size.

The dimensions are set from the very top of each board in the upper part of
the horn and from the very bottom of each board in the lower part of the
horn.

Click the image to open in full size.

To cut the 177-angle, use 89 degrees on each board.








The Kraken 210

JBL GTO 1014

See notes on how to read the dimensions in the upper Kraken 112.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
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Old 5th November 2011, 01:00 PM   #95
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Ihe inner depth as well as the height of the outlet hole of Kraken 210 is 280 mm







Kraken

Click the image to open in full size.

Last edited by Petter Persson; 5th November 2011 at 01:05 PM.
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Old 5th November 2011, 05:07 PM   #96
18Hurts is offline 18Hurts  United States
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Thank you very much for the 1x12 Kraken drawings!

It is now my winter project to build one of them with two sheets of plywood and a single GTO 12". Calculated the height, width, depth and weight, measured the corner in the garage and it is a perfect fit. It will weigh approx my body weight and with half the depth, a simple move with two people or a dolly. The plan is to eventually build a second one to go with my pair of line arrays to hold them in position and couple better as a pair.

I'm assuming the single 12 Kraken is tuned the same as the 2x12 original? The single GTO will be my Christmas present so it is a January/February project depending on if I can get some warm days.

What is the compression with the Kraken series? I plan on playing around with Horn Response this winter and will attempt a 16Hz tuned single 15" version. Since 12 inch woofers can handle twice as much compression, I'd like to cut that in half while playing with the Horn Response sliders. The single GTO 15 has the same efficiency as two 12's and a lower Fs--a 16Hz tuned Kraken could be possible (in theory) but I'm worried about the compression on such a large cone.

Thanks again for all your hard work and inspiration, Petter--the Kraken series are great designs.
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Old 5th November 2011, 11:58 PM   #97
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How does the 1x12 Kraken compare to the Lab 12 horn? (20-25hz tuning or so...) Kraken is a few inches taller, but not as deep...
Lab12 - Tapped Horn -
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Old 6th November 2011, 03:32 PM   #98
tb46 is offline tb46  United States
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Location: Texas
Hi,

Just a quick comparison between the Dual GTO1214 and the LAB12:

Regards,
Attached Images
File Type: jpg THs_Petter Persson Dual GTO1214_v_Don Snyder LAB12.jpg (80.6 KB, 368 views)
__________________
Oliver
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Old 6th November 2011, 03:52 PM   #99
Spuddy is offline Spuddy  United States
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Location: NH
Nice job with all the new renderings Petter! I'd be really interested in seeing if anyone out there with more measuring equipment would like to slap one of these together and list up some actual numbers, as I'm obviously not much help in that regard.. All I can say is that the 212 is far louder and deeper (and cleaner!) than my old workhorse Velodyne, but the set ups on this forum go borderline insane, so that probably doesn't mean much around here

Build people, build! I made the biggest Kraken model there is and it was less than $500 for everything. If you're a slightly crazy bachelor like myself with no WAF to contend with, you can't go wrong! If you're married... Good luck It's easily worth a small turf war for the theater though!
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Old 6th November 2011, 04:35 PM   #100
18Hurts is offline 18Hurts  United States
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Quote:
Originally Posted by Spuddy View Post
If you're a slightly crazy bachelor like myself with no WAF to contend with, you can't go wrong! If you're married... Good luck It's easily worth a small turf war for the theater though!
The dual Kraken has the WAF = 0 so I assumed (correctly) that you don't have a ball and chain. The single 12 version of the Kraken can fit behind a couch if you lay it down so has possibilities....heck, two of the singles will fit behind the couch if stacked on the "thin" side. Just tell your wife that it is a shelf behind the couch to hold pretty plants or something. The singles can also be used as stands to hold the surround speakers so there are ways.

I'm going to build the single version for garage use--more BAF instead of WAF. The Back Acceptance Factor comes into play since the thing will be moved when the arrays go outside for BBQs and house parties. The single would have about the same weight as me and I can see over it when moving it with a hand truck (dolly) and the 2 foot depth allows movement through door ways etc.

Calculated the "cut sheets" when using typical 4x8 3/4" plywood and the single Kraken takes less than two sheets with plenty of scrap for braces. There is one board that needs to be joined but I'd do it to the long board that faces the woofer that attaches to the "triangle". I'll glue it edge to edge and then put a overlapping brace inside the triangle to make it solid. The triangle will be filled with expanding foam so no worries about leaks.

As far as the LAB 12 VS the Kraken single, the LAB is slightly shorter but deeper and not tuned as low. It would be louder than the Kraken single but I want the lower tuning for pipe organs and the like--the LAB 12 won't do that. If I need more output, just build another Kraken single--can't tune a LAB 12 lower so I'm going low first and will add more when (if) I ever feel the need.

The Kraken single is very reasonable in price which is important for the WAF calculation. $96 for one JBL 1214, $80 for two sheets of AC rated void free 3/4" ply, $5 for glue and $7 for two pounds of screws and $6 for an input terminal or around $200 each.

In WAF math--under $100 for the speaker and nickles and dimes for wood and a few trips to the lumber yard.
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