2" 223Hz tractrix horns

[jwc]

yes Jeremy. As you know....I started building mine and I just basically don't have the time anymore. I was glad someone took on my plans and ran with it.

Is the mouth on your 225hz horn 24 x 12? Is the length just over 17"?

Thanks

jc

[PrestonTom]

That is a nice looking project. You make it look easy which is unfortunate because these things never are easy. Consequently folks like me get ambitious and try and tackle something that we don't have the skill set to accomplish.

That aside, you showed the tractrix expansion that you used for the horizontal contours. So far so good, and as far as I can see, they do in fact look like a tractix flare. However, the tractrix is the total expansion. I bring this up since I noticed you also have an expansion in the vertical direction. Unless I have missed something that would mean the horn expansion is "bigger" than the tractrix. Am I missing something?

-Tom

[jwc]

Tom.

That "flare" he posted is calculated in a way that it expands vertically and horizontally to make a prefect tractrix. The vertical expansion is accounted for.

The first "Edgar" horn I drew up was in error just as you described.

There is a "trick" to calculating that flare when you know a "constant" vertical expansion.

I am confident that at every millimeter distance straight from the throat center to the mouth center has an associated "area" that follows the tractrix calculation.

Having said that,, I'm not confident in automatic "success". We'll see.

jc

[Guest David H]

The corrections have been made to the graph [:S]

I dont know what divisions JW used, but when I measured his template, I used 1 Inch Divisions.

223 HZ horn info:

Mouth internal height 12" Not to scale, Reccomend build 1/2 flair then mirror for accuracy.

Length 17.5" I also reccomend adding 1 inch front and rear of the flair to be trimmed after complete.

Throat 2"

17.5"------------------------------------------------------------------------------------------------ 12"

17" ------------------------------------------------------------------------------ 9.50"

16" --------------------------------------------------------------------- 6.95"

15" -------------------------------------------------------- 5.53"

14" ------------------------------------------------ 4.55"

13" ------------------------------------------ 3.73"

12" --------------------------------------- 3.17"

11" ----------------------------------- 2.72"

10" --------------------------------2.36"

9" ---------------------------- 2.04"

8" -------------------------1.78"

7" ----------------------1.57"

6" --------------------1.39"

5" ---------------- 1.25"

4" -------------- 1.14"

3" ------------ 1.06"

2" ----------- 1.0"

1" ---------- .97"

0" ----------- 1.0"

[Marvel]

So the throat is 2" x 2", is that correct? That would mean the top and bottom start at the 2" (1" from center) and go to 12" (6" from center) vertically.

Very cool! Can't wait to hear what JC thinks ofit when he gets some testing and listening done.

Bruce

[Guest David H]

Very cool! Can't wait to hear what JC thinks ofit when he gets some testing and listening done.

That makes two of us.

So the throat is 2" x 2", is that correct? That would mean the top and bottom start at the 2" (1" from center) and go to 12" (6" from center) vertically.

Exactly.

[Guest David H]

The second horn is much nicer than the prototype, most of the jigs are built.

[Guest David H]

Side view

[GaryO75]

So what would be the recommendations for 2" drivers for this horn? Assuming it would be used as a midrange, low end about 400 Hz, and going to about 4500 Hz like the Cornscala II crossover Bob has put together, What would you guys suggest? I am looking for a good performing driver, but it should also be moderate in pricing ($150-300). Your thoughts would be appreciated.

Gary

[jwc]

Gary.

Dedicated mid drivers are harder to come by these days. B&C are still making them and released some new ones. pricey though.

Selenium has some cost effective ones that are in the price range you mentioned. I was just looking at their website the other day. I've never heard a selenium driver though.

Crites at some point was an Eminence dealer. It would be nice if he could become a dealer for a mid driver that is 2" and 16 ohm. Just brain stormin......but that would be an "easy fit" to accompany his existing networks, woofers, and tweeters. The Atlas is no slouch....but it would be cool to have a big midhorn 2" throat mid.[]

jc

[jwc]

Got the horns. Good build.

I will get the curves this weekend with two drivers. Klipsch K1132 and JBL 2446. Neither of these will go down to 300Hz. Anyone out there want to spare a 300Hz mid driver?????

jc

[jwc]

Would anyone like to make comment on this driver:

http://www.parts-express.com/pdf/264-216.pdf

jc

[Deang]

I personally wouldn't consider using a crossover point that low with any alloy diaphragm. There are only two 2" drivers that I know of that can go that low on the right horn, and one of them only goes to 4kHz. The other is the BMS 4591, a driver I really wish I would have had a chance to play with.

http://www.assistanceaudio.com/graphics/4591_freq.jpg

I think it's important to remember that the specified Fc or cutoff does not mean that's where the crossover point goes. For example, the K-400 has a Fc of 240Hz.

[greg928gts]

GotHover - I am playing around with building wood horns for 2" drivers. The layout you are showing with the curve of the horn I assume is in the center of the horn, so how did you go about figuring what the curve of the top and bottoms would be? They are slightly different no?

I'm not even sure anymore how I got mine figured out, I think I went through an entire sheet of 1/2" plywood! The last step was mounting one of the pieces on a jig that held it at the proper angle, and then tracing down vertically onto graph paper to check the curve. I then made adjustments to the piece and retraced until I got it just right.

Are you cutting the ever-changing angle on the tops and bottoms so they fit tight to the sides?

I am amazed at how much work has gone into the prototypes that I've built so far, I get tired just thinking about it.

Greg

[Guest " "]

The klipsch KM4 manifold with go below 300hz and cover the standard mid range of a heritage product up to 5K. It is a manifold with 4 K-55 drivers on it.

[Guest David H]

GotHover - I am playing around with building wood horns for 2" drivers. The layout you are showing with the curve of the horn I assume is in the center of the horn, so how did you go about figuring what the curve of the top and bottoms would be? They are slightly different no?

The layout I posted earlier is from the center. I posted like this so builders could make a half template and mirror to keep both sides identical. The top and bottom are identical. As for figuring the curve, I have no idea, I just followed the instructions supplied by JWCullison.

Are you cutting the ever-changing angle on the tops and bottoms so they fit tight to the sides?

Greg, I hope I am understanding your questions corectly. First I cut the bell shaped top and bottom sections, the sides are then mounted in a holding jig that is clamped to my saw table. The side angles are then hand sanded in with 40grit adhesive back 14"x2" automotive longboard sand paper that is attached to a 14"long piece of 4" pvc pipe. This process only takes a few minutes to sand, and because both pieces are being sanded simutaneously I get a near perfect fit every time.

I am attaching a pic to give you an idea.

[Guest David H]

yeah, I need a new piece of 40 grit paper. here is another pic of my DIY sander. BTW, I put the handle in a lowsy position, it really should have a pair of handles located near the outer edges of the sander.

[jwc]

I personally wouldn't consider using a crossover point that low with any alloy diaphragm. There are only two 2" drivers that I know of that can go that low on the right horn, and one of them only goes to 4kHz. The other is the BMS 4591, a driver I really wish I would have had a chance to play with.

http://www.assistanceaudio.com/graphics/4591_freq.jpg

I think it's important to remember that the specified Fc or cutoff does not mean that's where the crossover point goes. For example, the K-400 has a Fc of 240Hz.

Yes Dean. That Selenium driver used to come with phenolics. They changed it as of 1 year ago. I wonder if they are still available.

I've talked to assistance audio before. One man show. Nice guy. Prices are good. He is one of the few that carry the Ciare and the BMS line in the USA.

I also realize the cutoff point issue....just like my Klipsch K260 horns from the pro line were crossed at 400Hz with (4) K55's on a manifold.

But I'm not ruling out the 300Hz possibility. .........

jc

[capo72]

Got the horns. Good build.

I will get the curves this weekend with two drivers. Klipsch K1132 and JBL 2446. Neither of these will go down to 300Hz. Anyone out there want to spare a 300Hz mid driver?????

jc

When I first learned you were testing these horns for Gothover, I was thinking I should send you mine as well for comparison. Not you've got me thinking I should send you one of my horns and a JBL 2482 driver. They are supposed to reproduce pretty well down to 300Hz with the phenolic diaphrams. Let me know what you think.

Jeremy

[capo72]

GotHover - I am playing around with building wood horns for 2" drivers. The layout you are showing with the curve of the horn I assume is in the center of the horn, so how did you go about figuring what the curve of the top and bottoms would be? They are slightly different no?

I'm not even sure anymore how I got mine figured out, I think I went through an entire sheet of 1/2" plywood! The last step was mounting one of the pieces on a jig that held it at the proper angle, and then tracing down vertically onto graph paper to check the curve. I then made adjustments to the piece and retraced until I got it just right.

Are you cutting the ever-changing angle on the tops and bottoms so they fit tight to the sides?

I am amazed at how much work has gone into the prototypes that I've built so far, I get tired just thinking about it.

Greg

I don't know if you have seen it or not before Greg, but I have attached a link to the thread I posted when I went through this build. I think you should be able to see the way I handled a couple of the questions you are dealing with. Your skills are way beyond mine so this should be no problem for you.

http://forums.klipsch.com/forums/t/93132.aspx

Jeremy