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Dual 15 inch Corner Bass Bin - Cornscala dbb


jwc

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soundbound,

I had Cornwalls for years, loved the inpact, but knew that they were limited by the K600 horn. Always thought about a K400 for CW's. Spoke with Bob Crites about it and later he built the "test box". Then JC built the Cornscala, a more finished product. Both were CW bins(same size different shape) with LaS top ends.

I also ran four CW's stacked tweeter to tweeter. And again, thought about two CW bins in one box with a better top end. A few years earlier, a forum member (can't remember who-don't think he is here now) had built and posted photos of a single woofer Cornwall type bin that he had extended back into a corner to accommodate a large mid horn inside the cab. Same port size and cabinet volume, just different shape. Started talking to JC about that and he built the dbb's.

Make no mistake, JW Cullison did the math and the build. They are his design. Im just blessed to have them.

tc

PS: If you want to build, JC has CAD drawings posted a few pages back.

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When JC brought them to the Hope gathering one year I thought they should have been on stage with the band so they could really breathe.

GREAT WORK!!!!

Ian,

Man, that room in Hope was the pitts. If the dbb's really sounded like that, I would have used them for fire wood as soon as JC left.Super Angry

Having had several networks in them, these are by far the best. I had been listening to the same horns and drivers with ESN600's. When I cranked them up the first time, it wasn't the low end that I noticed first, believe it or not. It was the midrange. Just wonderful. (not to say that the LF doesn't kick my bu!!) The bass is much tighter than I imagined....as is.....

I recieved the first shipment of OC 705 for room treatments today. Looking forward to tuning the room so I can "lay the spurs to them"Wink



At lower volumes you could tell they sounded nice even in that horrible horrible room. Nothing sounded good in there loud. In retrospect we should have taken them outside and cranked them up.

Will those networks work on my khorns : ) Bring those down next time : )

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Outside without corners they would have sounded very lean and shrill without changes to the crossover...going from 1/8 space to 1/2 space is a 6dB swing at only certain frequencies, so the voicing would be all screwed up.

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Mike B...what the heck are you talking about?

.....

Thanks for the compliments. No one deserves those speakers more than you IB Slammin.

A lot of time went into this project. As IB put it and paraphrasing, these are a "big Cornwall" with some fat bass at SPL similar to a Khorn. The footprint is very similar to a Khorn.

I've had several speakers in my basement and these are hard to beat...I assure you.

I went through several networks and ended with the ESN designed by ALK. This network will ONLY work with a bass bin with two K33's or Crites woofers wired parallel.

The previous networks described in this thread work too.

I too thank those people metioned earlier for the help of this project and thank Ajsons for the CAD.

This isn't a complicated build and I would be thrilled to see others give it a try.

jc

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Mike B...what the heck are you talking about?

The difference between half- and eighth- space in reference to using your (or any home) setup outdoors.

Not much chance of them going outside, Mike. I have moved them enough as is[:'(] Five sheets of 3/4" plywood per speaker as I recall.

tc

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jwc,

I know this is an old thread but I am relatively new to the forum and this concept intrigued me. I would like to ask you a couple of questions if you don't mind.

1) You hinted in the thread that the angled back end as opposed to a square back changed the sound. What change, in your opinion, did it actually make?

2) The ports only go halfway up the height of the bass bin. Is the width of the ports the same as if they were under the woofer? Is the height of the two ports combined equal to the usual underneath port?

3) Would it adversly affect the sound if the two side ports were the full height of the bass bin but only half the width?

Thanks, LC

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1) You hinted in the thread that the angled back end as opposed to a square back changed the sound. What change, in your opinion, did it actually make?

The angled back is for the sole purpose of eliminating broad faced panels to reduce possible resonance and also to "hide" cabinet volume in the corner

2) The ports only go halfway up the height of the bass bin. Is the width of the ports the same as if they were under the woofer? Is the height of the two ports combined equal to the usual underneath port?

If you look at each woofer on the dbb, the ports immedially to the side are an identical split of the late cornwall port. Clarify "width" for me.

3) Would it adversly affect the sound if the two side ports were the full height of the bass bin but only half the width?

I had given some thought to make the ports look like the old Onken cabinets where the vertical ports spanned the heoght of the cabinet. You could "recalculate" the port to make this work..

BUT...My attemps were to port and sound like the cornwall as much as possible..

jc

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These are the Cornscala dbbs I am building with K-33's Altec 806's and 511B horn and Eminence APT 50's with my horn. The bass bins are 25.5 " wide by 24" by 24".I need to build 2 more bass bins. I have finished the tops as seen in the photos and went with double thick walls on the sides of the bass bins using a idea from a previous Cornscala build .I have the other pair of K-33's underneath in a smaller box so i could get a idea of what they will sound like.

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I also set up the crossovers so I can change them from a type A to a Type B crossed at 500Hz so I can run them with 2 woofers or just 1.I ran the taps to a terminal strip so I could change the tap settings without having to unsolder anything and have 2 inductors set up the same way 1 for using 2 woofer or 1.

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I ran the taps to a terminal strip so I could change the tap settings without having to unsolder anything...

I've been thinking of doing that on the crossovers I built for my LS. It's a great idea.
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JC,

You are the ultimate tinkerer, for sure. I understand you are not able to use your Mega MWM collection to kick this kind of setup to the curb, I get that.

As far as the inductor, just get 2 of them. You will have the right value and power handling for each woofer. You can even use separate stereo amps for each woofer, few by a Y input, where one of the sections would also feed the top end and the other would not, since the impedance and effciciency of the horns would be about 7-10 db more than each respective woofer

Even the funkiest of funk will not saturate 2 AA network woofer chokes. I used cornwalls commercially back in 1973, with 400 watts of Dynaco power, so I speak from experience.

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JC,

You are the ultimate tinkerer, for sure. I understand you are not able to use your Mega MWM collection to kick this kind of setup to the curb, I get that.

As far as the inductor, just get 2 of them. You will have the right value and power handling for each woofer. You can even use separate stereo amps for each woofer, few by a Y input, where one of the sections would also feed the top end and the other would not, since the impedance and effciciency of the horns would be about 7-10 db more than each respective woofer

Even the funkiest of funk will not saturate 2 AA network woofer chokes. I used cornwalls commercially back in 1973, with 400 watts of Dynaco power, so I speak from experience.

Claude. Not sure what your post is referencing too.

In the beginning of this thread...the initial network I used was a Type A network with an extra 2.5mH inductor.

jc

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