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Bruce Edgar Tractrix horn project


Arash

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Canyonman what tweeters you had before? How do you think sound improved and what crossovers are you using?  

 

You have a klipschorn like mine with bms and vtracs. Why did you crossover @ 80hz. My khorns can go down to 40hz and are sounding nice. What benefit you had from crossing @80hz?

kodomo,

I started with the k77 tweeters then when with APT200's also tried the Beyma's, the Fostex tweeters put a nice touch of air and elegance in the sound. Plus and I mean a big Plus I put them on top of the cabinets and was able to time/phase align them with the mid drivers big plus!!! I had ALK Universal Xovers for years, now I am using a custom built set using the same values as the Universal's just much better parts. Like 8 gauge air core inductors on all three drivers, all Sonicaps and Dueland resisters  and a custom autoformer I think by Northcreek. Anyway the sound is just ALOT smoother than with the Universal's. I never heard the need for subs before just listening to my system but, when I started using gear to measure the frequency response it plainly showed the need for them. I am sure this is due to the fact that I use a 2wpc 45 type amp. The measurements showed the low end rolling off at about 90hz or so, so I crossed the mains and subs at 80hz and have never looked back. A very seemless intergration of the subs after some trial and error and plenty measurments!!! I now have a pretty flat FR from 15hz to 20khz with about a 6db drop from one end to the other.

Edited by canyonman
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actually I calculated a cf190hz Edgar style horn for a friend and thought maybe someone else is also interested to build such a horn so I'm sharing the plane here though it's not something very unknown to many of you:

 

 

40cm height to 80cm width ratio would be 1:2 not 1:1.5 :) besides you don't need a 80cm horn to get down to 190hz cf.  I calculated it for you with following details:

 

width to height ratio: 2:1

cuttoff freq.: 190hz

height of the horn: 35.69 cm

width of the horn: 71.395 cm

lenght of the horn (throat to mouth): 56.73 cm

 

you can download the Coreldraw file with 100% actual dimension: cf190 plan.zip

a preview of what you'll find in Coreldraw file:

 

post-41711-0-10680000-1430388545_thumb.p

 

feel free to ask me if you have any problem with file format or extension or whatever.

Edited by Arash
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Arash, this seems exactly like Greg's horn. I use it with BMS 4592md mids. They sound great. Which tweeter and midbass you are planning to use it with. Have you done a crossover design? Check http://www.klipschupgrades.com/crossovers.shtml I am using the VTK400. Its great to have the flexibility on adjusting mid parameters and woofer cutoff point. I have padded down the bms drivers around 9db's.  have also added 22 and 2.2 resistors to tweeters to pad them down 3db's, get the woofers cutoff lower and have a more flat response now. I am happy overall. I am planning on building a nice horn subwoofer. I have a few plans in my hands. I also will change the tweeters to fostex t500amkII's.

 

If you have these, why not try and build a nice midbass. Maybe you can try the 80hz midbass at Inlow (http://inlowsound.weebly.com/diy-80hz-midbass-horn.html). It seems with your knowledge, the plans supplied and your equipment it ll be easy for you.  You can then add a 20hz to 80hz hown sub to complement that. If you have good tweeters like the fostex ones (t900 or even t90a) then you are set. People with upgraded khorns get a good sound and sometimes stop investigating. I have been on a continous journey. I have covered 20 to 20k now and having the actual full range is really nice and its hard to turn back. Now I am looking for more resolution. Thats why I am going to change my sub to a horn sub and tweeters to t500amkII.

 

yeah it seems so. it's a fc253hz horn just like Greg's V-trac. I'm going to use BMS 4592ND-mid on it. the tweeter is Beyma CP-25. for the lower notes I'll use a LS-like folded horn I've been tweaking for months not. I would say it's also very similar to Greg's Vittora bassbins.

I'm not a carpenter but I can build things with wood. veneer is something new in my area but I'm working on it and experiencing different glues and ways of applying veneer on the BB plywood. for now it's a horn I built with veneered BB. not bad but not the end of my endeavor. we have 1ton air press in store and I'll soon build a vacuum bag press, then I would go for other sizes of Egdar style horn and maybe biradials

 

attachicon.gif6952932a5b9142c5d5a70a9211290add46d9cd2e82f8c8b908236d9fa8d44f03.jpg

 

beautiful -

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I couldn't wait any longer, I had to try and build the cf190hz horn, so I did! I built the horns, now I will need to make throat adapters and think about finishing them. I used marine plywood for top and bottoms and 8mm bendable plywood for the sides. They still fit on top my klipschorn bassbins but without the tophats, as they are bigger than the tophats themselves. I have the BMS 4592nd-mid 16ohm and I have been crossing it around 380hz. My midrange horn was made by Greg (beautifully) and it is cf 260hz. When crossed at 380hz, there is a slight problem with group delays. I want to get rid of the phase shift that is happening because I was crossing close to cf. Now I will have about an octave and hopefully it will be over.

 

The crossover I have lets the midrange rolloff by itself. The BMS rolls off around 6khz. How do you think it will interact with this horn? Is larger horn bad for higher frequencies, will I have more beaming?

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post-55716-0-67660000-1430804711_thumb.j

Edited by kodomo
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I filled all the gaps and sanded the hell out of them. I left them at a painting atelier and am going to pick them up on Friday. I can not paint at my place :(

 

 

She likes it . . . Your cat, I mean.

They look great. I'm eager to learn your impressions.

 

I have two cats in the house, and they were both very interested in the horn. I had to keep it away from them, as they wanted to crawl inside of it to sleep!

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Here they are painted. The second photo is to show the relative size to a klipschorn. I will take off the tophats and put these. This weekend will be a lot of listening and measuring and listening and some more listening :)

 

post-55716-0-08820000-1431069450_thumb.j

post-55716-0-64740000-1431069471_thumb.j

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And here they are on top of my horns. I am very happy with the integration to the bassbins (soundwise) It sound even more effortless then my fc253hz tractrix's built by Greg.

 

I put some tops on the bassbins and put these on that. I am planning to make a rigid rectangular piece and attach it to the lips. That bracing will help with the sound and make it even better according to what I hear. So not many problems, I am overall happy with this project!

 
Here are some shots

post-55716-0-37800000-1431356265_thumb.j

post-55716-0-98680000-1431356450_thumb.j

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actually I calculated a cf190hz Edgar style horn for a friend and thought maybe someone else is also interested to build such a horn so I'm sharing the plane here though it's not something very unknown to many of you:

 

 

40cm height to 80cm width ratio would be 1:2 not 1:1.5 :) besides you don't need a 80cm horn to get down to 190hz cf.  I calculated it for you with following details:

 

width to height ratio: 2:1

cuttoff freq.: 190hz

height of the horn: 35.69 cm

width of the horn: 71.395 cm

lenght of the horn (throat to mouth): 56.73 cm

 

you can download the Coreldraw file with 100% actual dimension: attachicon.gifcf190 plan.zip

a preview of what you'll find in Coreldraw file:

 

attachicon.gifcf190hz bruce edgar horn.png

 

feel free to ask me if you have any problem with file format or extension or whatever.

 

 

Any way you can share a .dwg file?

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"How would one of these work as part of a 2-way system crossed around 400-500?"

 

It would beam real bad on the top end, you will need a tweeter.

 

 

 

Is this the case with all horns of this type?

or would a shorter horn designed for the XO frequency beam less?

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I cross around 6.5khz, it beams but not more than volti v-trac.

 

The BMS 4592nd-mid 16ohm driver has a bump around 4khz and that is heard. The horn itself resonates a little as it is not braced to a chassis like the volti horn or Klipsch horns. This causes some sounds to be located coming from the speaker (less than stock klipschorn). They cant detach as good as a well braced one like v-trac. I think as it resonates it also creates a timbre which colours the sound. These are the areas I have to work on.

 

However, the sound is more relaxed (sounds like more headroom) and has more dynamics. The integration with the bass is better. My crossovers that Greg built have 6db rolloff around 360-380hz. He has put 3 choices for the bass inductor. Low, mid and high. With the v-trac, the meaurements looked better when I used to choose the high setting but then it muddied the presentation, and it did not sound good. When I used mid setting, I was compromising some spl for clarity. There used to be a dip around 380hz. When choosing low, it lacked certain weight and had a bigger wider dip. Now with this horn, I can choose the low setting but it still measures very flat and sounds very clear. I can hear the tone of the bassdrums and the body of the bass guitars better. 

 

If the height wouldn't be an issue, I would build another tractrix with 1" mouth and 1khz cf, and cross it around 2khz. Then cross to my tweeters around 8khz. To do that, I have to change the bassbin too, otherwise the midrange and tweeters would be too high. One can use Inlows 80hz midbass with these tractrix I have built and 1khz tractrix on top of that plus tweeters. I have built tapped horns that can work below that, though 80hz would be too high for them to cross and sound as good as the klipschorn bassbin. I may put the v-tracs back on top one day, then build a 5 way system with what I have built :)

Edited by kodomo
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