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jwc

Dual 15 inch Corner Bass Bin - Cornscala dbb

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Ok guys,

Call me crazy. I just cant seem to stop cuttin.

BS Button and IBSlammin have given me motivation to take on a bigger task after the completion of the Cornscala. The idea was to create a Cornscala with more Bass. The option would be to have an 18 woofer or dual 15. The idea with the dual 15 K33 was to keep the same sound but increase the SPL about 3 db for the Bass Bin.

The depth and width are the same as a Khorn. When and if I add the HF section, it will be the same height as a Khorn. Attention for all who don't have the corners for a Khorn (I know you can build a false wall for the Khorn).

The attached photo is the beginning of a project Cornscala dbb (double bass bin). I only built one for now as I am sure there will need to be some tweakin of the network. I have posted this now because I am gonna crank this up this weekend to give it a test run.

I NEED OPINIONS HERE!

The current setup is a Type A network with odds and ends parts (ignore the B label). The tweeter is on tap 5 and the mid is on tap 4. The sqwauker is crossed at 400hz. There is a JBL 2404H here that I know will be a little hot.

The biggest tweak in my opinion will be the low pass. With two K33s in parallel the bass bins will be showing 2 ohms to the network. Yes this will throw things off. Currently the inductor is 2.5 mH. With two woofers I think it should be cut in half in value to keep the crossover the same. This will be determined.

I think making the low pass like the AK-3 would be nice with a 4 mH inductor and 100uF cap changed to a 2 mH inductor to a 200uF cap.

WHAT DO YOU THINK ABOUT THIS?

jc

01130013.jpg

post-16499-13819267168956_thumb.jpg

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Here is the port design. This is a Split port version like a 77' Cornwall. The port volume is 713 cubic inches and the port openings total is 49.125 square inches. The volume of the cabinet is right at the volume of a Cornwall minus the drivers, horn, and network.

01030041.jpg

post-16499-13819267170776_thumb.jpg

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Todd,

Don't slit your wrists yet! You need to come over and watch an MSU game and listen to these (if they end up soundin' worth a damn).

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Well, the subs are still useful for movies; not natural for 2 channel music IMO. The HSU's will sink to 20hZ or below; these K33s won't go that low. However, I am hoping that they have the "lower" fast bass like my Cornscalas.

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You might need to put your seat belts on JC. There is no way that this will not sound good. I'll betcha that the hot tweeter may need to be left that way, playing catch up.

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You might need to put your seat belts on JC. There is no way that this will not sound good. I'll betcha that the hot tweeter may need to be left that way, playing catch up.

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JC, I too am curious and hopeful of the sound reproduction you attain. I think there is definitely a market for corner Cornwalls, but have been warned of the internal reflections. A single bass bin corner Cornwall could have the same footprint and appearance of the Shorthorn, but with better voicing. In this design, the porting would be between the "legs" of the Shorthorn faceframe, but there wouldn't be enough depth for a K400. I believe the split porting, as well as the placement are good ideas.

Would there be any benefit to having one braced enclosure instead of two, or having the ports together?

Have you seen the patent drawings for the 2 15" woofer Theater Klipschorn? Quite interesting, but your corners are "built-in". Keep up the good ideas.

Any thoughts about different mid drivers or horn lenses?

Chris

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Nice work JC! Keep us posted on your impressions as you tweek it.

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Chris,

No I haven't seen the plans you are speaking of.

I came up with several plans to make just one port just like my cornscalas. All of those attempts failed in my mind due to the height of the bass bin. Anyway that I would arange it, the total height with the HF cabinet would be way taller than a Khorn.

About the Corner. Well this can wedge into the corner tight or it can be pulled out some. It can also be toed in if needed. Basically, place it like the room needs it. Right now I have it toed "out" just a little so that the HF drivers will point to my head.

Another reason for this shape was to use the corner to help take up some of that 12 foot cubic volume. This involved the volume calculation of a trapezoid in addition to a rectangle. This volume accomidation allowed the placement of such a large cabinet in just about the same place a Cornwall would sit. In other words, the front of this bass bin sits about as far from the corner as the front of a Cornwall would sit from the corner.

Testing of different mid horns is planned.

jc

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Try an iso-barik mounting. You can have it almost flat to 33Hz, in a 10 cu ft cabinet. Then the drivers would be hidden and not be able to be damaged by foreign objects. You shouud still get enough high end out of them to cross over smoothly.

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I have read about that kinda cabinet. I also contemplated other woofers and other types of cabinet designs. However, I wanted to keep the K33s "tuned" just like in the Cornwall. There are several ways I could get the bass lower but then I would be experimenting with the Tuning of the K33. This wasn't my goal. I want to try and keep the same sound but increase my dB only. I want to keep the "Klipsch" sound (granted there is a JBL tweeter there).

There is a strong following for the bass "slam" of a Cornwall. I thought of ways of incorporating the dual woofers of the KLF30 with a heritage mid and tweet. Althought the specs look better for the KLF low end, I didn't seem to get the vote for a better "sound" than the Corn.

The front of the bass bin will have a custom grill just like the Cornwall. Damage risk would be no different.

jc

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Will probably hook up tonight. Working today. I need some of the rubber Nails to dry a little more.

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----------------

On 7/9/2005 9:28:39 AM jwcullison wrote:

Will probably hook up tonight. Working today. I need some of the rubber Nails to dry a little more.

----------------

I thought for a moment I had accidently logged in to one of the internet dating forums.

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