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Epic CF3 Bracing & Damping Project


kapsnb01

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Just got my new to set of Electrovoice DH1A monsters today. 23.5 lbs nine inches in dia. 5 inches deep, three inch titanium diaphragm with a two inch exit. Running them with my CF3 networks (have both rev 1 and rev 3 sets) 2 inch exits. Using six inch long Karlson Tubes made from rolled writing paper (2 inch id) tape hand drawn and cut K-Slots tubes are at ear height aimed at the listening position at ear level with the slots cross fitring at one another, tubes are parallel to the ground. Sound is very good. I like this set up more than the stock horns and K63KN. Will post a picture of driver and tube soon so you can get an idea of what a K-Tube looks like and how freaking large a DH1A actually is, massive is a good place to start. Best regards Moray James.

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Sounds awesome Moray. Looking forward to seeing the setup, especially those monsters. At 23.5lbs, those things have to just be huge. What are your impressions of the sound so far...I know you mentioned that you like it, but what type of differences are you hearing? I've got to believe that it's pretty noticeable with that much of a difference in size/weight.

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Well I have tried out two totally different crossovers dirst the CF3 networks and then the KLF20 networks both work both need adjustment but both work so I am scratching my head a little. Please note this is not a direct drop in but is close enought to play with and get a very good sense of how they sound. I would have to say that I am most impressed by combining the normal mid and tweeter range into one driver (most three way designs) and am looking forward to seeing how low I can run the DH1A in the two way CF3 which will be much lower than the K63KN can go. Terrific sense of control composure detail impact ease openness. The big diaphragm is cleaner soundingand yes it is huge but after hearing it I wonder why more people are not using them. The DH1A imparts so much impact and attack to the bottom end it transforms the woofer if that gives you any sense of the range this thing has. I cannot imagine anyone not being immediately impressed. I will pull it apart later and see if I can do my usual compression driver mods and see how it responds to those but it is working so well there really is not much that I feel I need to change about it at the moment. The cool factor is as big as the driver. You have to admit having a tweeter that weighs in at about double your average woofer is not something that will go unnoticed. How good it sounds is also not likely to get missed either. Best regards Moray James.

PS: sorrybut I just borrowed a camera but cannot for the life of me get the pictures down loaded so that I can post them. If you have no idea as to what a Karlson K-Tube looks like Google images is your friend.

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Sounds awesome Moray. I Googled the k-tube and got a couple images. Are these what you're working with? Just want to make sure we're on the same page. That seems like a cool project...you have me thinking, that's for sure. Thanks!

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Hey Brian: yes those are K-Tubes. The first one is more of a parobolic taper the second is made with an ellyptical pattern wrapped around the tube which results in an exponential looking slot. The tubes are a 1/4 wave length of the driver resonance. Both the photos you have shown are typical configuration where the slot either faces up or down and the tube is set at some angle either up or down. In my case I have decided to cross fire the slots across the room left to right and right to left. This way the outside walls are not receiving any immediate (direct) energy so no immediate reflections of energy. I run the tubes at seated ear level parallel to the floor and I point them at the lostening position. The slot profile has an impact upon the dispersion and the bandwidth. Best regards Moray James.

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Here is a paper roll K-Tube roughly taped on to a Klipsch K63KN driver. As rough as these look they still manage to sound wonderful. DIY does not get any better than this. You can roll a pair of new paper tubes then draw on a profile and cut it out with scissors then tape the tube to the driver and be listening in under ten minutes start to finish. Hope this is of interest. Best regards Moray James.

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That DH1A is a beast! You're right though...definitely looks like a pretty simple DIY job to get that done. So, you've got the side tube cutouts facing each other, if I understand you right. I bet that sounds pretty impressive with that huge driver now.

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That's it the K-Slots cross fire each toward the opposite speaker. The one inch tube on the K63KN sounds absolutely great, the two inch tube on the DH1A is a whole other level. You really have to hear it and you understand why so many make the jump, why more don't is the question. Large format is very special sounding. Less than an hour of your time and you will understand why K-Tubes are special. In three inch diaphragm two inch exit drivers the EV DH1A has been a leader from the day it hit the market and it remains one ot the ellite drivers today. Think of the fun you can have swapping profiles with your buddies. You can havee the biggest tweeter on the block or in the club. Best regards Moray James.

PS: the way to making many tubes fast to play with is to make a mandrel of the size you want first to roll them on, one layer of paper and a small overlap and use some thin wire as a keeper to make sure the paper tube stays round after you cut the slot.

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  • 1 year later...

+++++++++++++    NEW POSTS DEC 2014   +++++++++++

 

I have recently come into some Electro Voice EV DH1A compression drivers (CD).  I had planned to upgrade from the stock K-63-CN CD on my CF-4, which uses dual 12" woofers. (the horn has been damped with white silicon seal)

 

post-58280-0-57700000-1418362849_thumb.j

post-58280-0-07940000-1418362692_thumb.j

 

This post should illustrate the point that there is a difference between knowledge and understanding.  I have read many posts on this, but until now I I don't think I understood what was being said.

 

Moray:  Has been a big proponent of the DH1A as an upgrade to the CF-3 and CF-4.  You can see his comments directly upstream from this current post on his use of the DH1A for his CF-3.

 

What I think I did NOT understand, is that Moray placed the DH1A on TOP of the cabinet, and instead of using the stock horn, he uses what is called a Karlson tube, or K-tube.  (see his post #70 directly above)

 

Moray, am I correct so far?  And correct me if wrong.  I'll continue after that.

Edited by wvu80
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+++++++++++++    NEW POSTS DEC 2014   +++++++++++

 

I have recently come into some Electro Voice EV DH1A compression drivers (CD).  I had planned to upgrade from the stock K-63-CN CD on my CF-4, which uses dual 12" woofers. (the horn has been damped with white silicon seal)

 

attachicon.gifIMG_4258.JPG

attachicon.gifIMG_3823.JPG

 

This post should illustrate the point that there is a difference between knowledge and understanding.  I have read many posts on this, but until now I I don't think I understood what was being said.

 

Moray:  Has been a big proponent of the DH1A as an upgrade to the CF-3 and CF-4.  You can see his comments directly upstream from this current post on his use of the DH1A for his CF-3.

 

What I think I did NOT understand, is that Moray placed the DH1A on TOP of the cabinet, and instead of using the stock horn, he uses what is called a Karlson tube, or K-tube.  (see his post #70 directly above)

 

Moray, am I correct so far?  And correct me if wrong.  I'll continue after that.

Yes correct. I use a two inch ID paper tube ( a single wrap and close it with scotch tape) (looks like a bishop's cap) with two cutaways and I position the tube at ear level so that the cut away sections are open in the vertical plane and I fire them directly at the listening position. So in this position the remaining solid portions of the tube are each left and right of centre. The paper tube is very flimsy even with a single cut away and more so with two (this is a bonus as it stores very little energy) and it requires a "keeper" tube in the form of some twist tie wire pre formed on a 2 inch mandrel you slide this over the paper tube to help keep it round. Hope this helps cannot seem to get pictures to attach don't know why. Best regards Moray James.

Edited by moray james
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Thanks, Moray.  Your posts #70 and #71 have your pics with the Ktube. 

 

Part of my problem was the thumbnail was too small, and when I clicked on the pics, they were so large they got fuzzy and the whole picture would not fit on my screen, I had to scroll.  The result was (not metaphorically speaking  :rolleyes:  ) I couldn't see the big picture.  It was 10 times easier for me to understand once I had the CD's in my hand.

 

This has been a good learning experience for me.  Thanks again for all your help and advice.  :emotion-21:

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both of those pictures show singe cutaway K-Tubes. As I mentioned I am now using a double cutaway tube. I just wanted to make that clear. Sorry I don't have a picture of a double cutaway will see if I can find one. Best regards Moray James.

Here is a picture of a Bob Reams version for a woofer but you will get the idea. I run my paper 2" ID double cutaway turned 90 degrees.

post-44375-0-09060000-1418409602_thumb.j

Edited by moray james
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  • 3 years later...

Dear all,

I'm considering redamping my cf-3 rev 3 with good quality foam.

Can you advise me?

What about this type of foam?

https://www.toutlehautparleur.com/laine-d-amortissement-15-mm-coton-100-x-73-cm-speciale-acoustique-avec-face-adhesive.html

 

And where should I apply it? On every internal faces?

 

The original foam look cheap. And I LOVE my speakers so if I can upgrade it... ;)

 

Thanks for your help!

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