DIY Round Tractrix Horn

[Rudy81]

As close as the above results are, I wondered why I could hear better high end response on the Jabo horns. My horns do not point directly at the sweet spot, so I figured the difference could be more pronounced in the polar response area. Here is a plot with the microphone apporximately 45 degrees off from horn center. This is where the better made Jabo's really show a difference.

[Rudy81]

Finally, the Jabo horn on axis vs. approximately 45 degrees off. I was able to work on basic voicing with the new horn and will keep setting things up tomorrow. If I decide to keep the Jabo horns, then it will be off to paint at some point. BTW, bang for the buck, these Jabo's are hard to beat when compared to the Orphean or any of the other offerings for spherical horns that are somewhat professionally made.

[DrWho]

I thought exponential was supposed to beam more than tractrix?

[Rudy81]

I thought exponential was supposed to beam more than tractrix?

I know. That was one of my hesitations when getting the Jabos. Remember that the Tractrix is a DIY project and who knows what the true shape of the horn is....although I worked hard at reproducing the tractrix curve I had cut. Also, the Jabo horn is about twice the diameter of the DIY and I don't know enough about horn technology to know if that has any effect.

I now the better response was both heard and tested. That seemed to be the biggest difference.

[mikebse2a3]

Hey Rudy

Thanks for posting your tests and impressions......very interesting.

mike tn

[Rudy81]

Based on my listening impressions and the various measurements, these Jabo horns are better enough than my DIY effort to keep. Today was paint day. Lightly sanded the horns and went with Black Satin Lacquer for the horn and my DIY stands. I forgot what a nice finish lacquer gives. At some point I will have to disassemble my DBB bass bins, sand them, and shoot them with this Black Satin Lacquer. Oh well, another project for another day.

Pictures to follow.

[Rudy81]

Completed DBB with Jabo Horns.

[Rudy81]

HT front speaker array. The tapped horn subs are now standing upright behind the screen for a cleaner look. Crappy picture since I can't use a flash due to the screen retro-reflectivity.

[Rudy81]

Jabo closeup after lacquer paint.

[Arash]

where can I buy a pair of Jabo? it shouldn't be too heavy... is it?

tnx

[Rudy81]

They show up on eBay weekly. Run a search for Jabo Horns and they will show up. There is an auction currently. They are shipped from Germany. No, they are not heavy at all.

[Arash]

They show up on eBay weekly. Run a search for Jabo Horns and they will show up. There is an auction currently. They are shipped from Germany.

tnx dude... how much is a fair price for a pair?

[Rudy81]

They seem to run around $340-$350 plus shipping from Germany. Frankly, I think they are a great deal. Werner is the gentleman who makes them and eventhough I didn't buy directly from him, he was very helpful in my transaction with a US seller. I paid $375 delivered for mine and have no regrets. Werner indicated the horns are exponential and could be used down to 400Hz, which is well below where I have them crossed due to my driver. However, my DBBs can go up to well past 400Hz no problem. So, I was not concerned with a very low Fc.

I just finished running Audyssey Pro and the Audyssey calibrated mic verified the independant sweeps I had taken. The horns performed very well. Orphean horns, tractrix, will cost you well over $1000 shipped. Most other contenders I have found will cost at least that much or more once you get them shipped.

Good luck.

[DrWho]

Rudy, have you played around with the $35 QSC horn?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=245-625

I
know it's not a circular horn, but I would be very curious to hear your
impressions on it. It's a 1" throat, so you'd need different drivers.
The BMS-4550 is good to about 900Hz with this horn after a little EQ and
sounds really good in my opinion. The polars are also extremely well
behaved above 2kHz (below that, the horn is just too small). My system is gonna be torn apart here in a bit, so I wouldn't mind loaning you some stuff to play with if you're interested.

I
wish it would dig a bit lower, so I'm working on my own homebrew at the
moment. Attached is a photo of the one intended to match the application
of the QSC horn, but I think I might try building one large enough to
support a 500Hz xover since the BMS should be good for going at least
that low.

Also, have you done any experimentation with MTM
alignments, or looked at the polar response of your dual woofers? Now
that I can measure it, I've noticed that achieving perfect summation at
the xover frequeny may not necessarily be the ideal approach. I've got a
ton of measurements uploaded to Picasa, but didn't want to spam your
thread if you didn't want to go off on that tangent. I ended up buying
ARTA (for like $100 or something) so that I could do polar response
measurements. Anyways, here's a link if you want to check some of them
out:

https://picasaweb.google.com/mebentz2/Audio

Anyways,
that's really cool to see the measurements correlate with your
perception. Have you talked to Werner to find out more specifics as to
why he calls it exponential? The exact exponential is part of the
hyperbolic family, so I'm wondering if maybe he's doing something
slightly different? John Post's thesis on Tractrix Horns compares
against exponential horns and shows the difference in polar response
(measured and predicted), so I'm curious how the two data sets are
related:

http://forums.klipsch.com/forums/storage/3/814933/post_thesis_ut94.pdf

If you haven't read it, it's a good read, although it's a bit on the technical side. Anyways, the shot of your horn doesn't look very exponential, so I'm wondering if maybe something got lost in translation when describing the flare type.

Anyways, been enjoying this thread quite a bit. I'd love to swing by sometime and hear what you're hearing.

[Rudy81]

Mike,

Please feel free to take this thread in a more technical direction. I could use the information.

No, I have not attempted to take any polar readings on the dual woofer bin, but since the speakers are use exclusively in a relatively small room, I am not sure the polar information is going to make much difference.

I realize round horns have a poorer polar dispersion than many of the other alternatives, but my experience with various horns has led me to appreciate the larger soundstage provided by the round horns....both DIY and professionally manufactured.

Thus far, I have tried the stock Klipsch horns on all the Heritage models, ALK's Trachorns, Greg's original 2" wooden horns with BMS drivers, P. Audio 2" horns and now the round horns.

Werner's english is way better than my German, but there is still a little language barrier and he is rather brief in his responses. I don't know exactly why he says his horns are exponential, but that is what he told me. I am going to check the Jabo's against my tractrix patterns (the ones I used for the DIY horns). Just looking at the Jabo's, they certainly 'look' very similar to my DIY effort, but the exact curve is difficult to discern. I know it is not a LeCleach curve after showing the pictures to the Azurahorn builder.

Please expand your comments on the crossover summation.

[Blvdre]

That QSC horn was one of Zilch's (RIP) favorite values, used in some of his Econowave designs. I have a pair on the shelf waiting to be used. Z's favorite design was the QSC mated to a BMS 4552 (or 4550?) and the Altec 414-8B.