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Old 15th August 2011, 03:53 PM   #2121
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Quote:
Originally Posted by mwmkravchenko View Post
Man !

I read through the manual and it is not that easy to send you to the right page and show you how to export the information.
Thank you very much Mark! You've been very helpful.
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Old 15th August 2011, 03:54 PM   #2122
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Your welcome.
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Old 15th August 2011, 04:17 PM   #2123
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Quote:
Originally Posted by mwmkravchenko View Post

Width Flare is the type of horn Con Trac Hyp or Uni. Uni is a horn where you set up Hornresp to make a horn having two parallel side walls and the rest changes. In other words you are specifiying the horns width.
Mine only has Con Exp or Uni, there is no Trac option in that box. I have version 28.40 of the program.
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Old 15th August 2011, 04:19 PM   #2124
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Here's what it looks like.
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File Type: jpg 12PE32 export horn data.JPG (44.4 KB, 113 views)
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Old 15th August 2011, 04:44 PM   #2125
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My mistake.
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Old 15th August 2011, 05:47 PM   #2126
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Quote:
Originally Posted by mwmkravchenko View Post
1/8th space is a very optimistic place to be that does not really exist in normal listening environments where you would be using this type of a horn.

Simulate it in 2 Pi and see what you get.

And if you are close to a wall and have good boundary reinforcement from say a concrete basement you could get away with 1 Pi.

1/8th Pi only really works with a concrete floor walls an ceiling.

As in perfectly reflective surfaces.
So, if the walls are hard plaster and the floor is concrete covered with carpet, do you think that this would work for 1/8 space? I have that in my basement.
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Old 15th August 2011, 06:02 PM   #2127
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Quote:
Originally Posted by David McBean View Post
Hi dirkwright,

The tractrix horn you are proposing has a severely truncated mouth. In such cases a simple exponential flare having the same S1, S2 and L12 values will normally perform just as well. Tractrix and Le Cléac’h horns are really intended to have fully-formed mouths. Otherwise, there is little to be gained in using them - it is just an unnecessary complication :-).

Kind regards,

David
I used your System Design tool to make a 1/4 size 60Hz tractrix horn and it made a horn with a mouth area of 6539 cm^2. Which is very close to what I calculate from the 1974 Dinsdale article, where mouth area = WL^2/4Pi, and then divide that by 4 to get a 1/4 size horn. (WL = wave length of cut off frequency for the horn)

Are you saying that tractrix are only good if they are full sized horns? Why would that be the case? I wanted to use a tractrix for the bass because they are shorter than a hyp-ex type.
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Old 15th August 2011, 09:58 PM   #2128
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How would I model this horn in your software? I don't understand what you mean by parallel and series connected drivers. Do you mean electrically or acoustically? I can't even figure out how drivers could be connected acoustically in series.
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Old 15th August 2011, 10:04 PM   #2129
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Quote:
Originally Posted by dirkwright View Post
Are you saying that tractrix are only good if they are full sized horns? Why would that be the case? I wanted to use a tractrix for the bass because they are shorter than a hyp-ex type.
If you look at fig. 5 in part 1 of the Dinsdale article, you will see (to a large part) why: when the horn is shortened, the tractrix curve is very similar to a pure exponential horn. The differences grows the closer you get to the full mouth size.

(BTW, if you read somewhere that the wavefronts in tractrix horns are spherical, while they are plane in exponential horns, that is not true. This is only the assumptions made when developing the equations. The shape is something like flattened spherical caps in both kinds of horns. Hornresp takes this into acount in the model.)

Regarding reactance anulling, the idea is to make the negative reactance of the rear chamber equal to the positive mass reactance of the horn. This way they largely cancel, and the load seen by the driver is mainly resistive in the working range. It is first described by A.L. Thuras in US patent # 2037185.

Bjørn
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Old 15th August 2011, 10:07 PM   #2130
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Quote:
Originally Posted by Kolbrek View Post
If you look at fig. 5 in part 1 of the Dinsdale article, you will see (to a large part) why: when the horn is shortened, the tractrix curve is very similar to a pure exponential horn. The differences grows the closer you get to the full mouth size.

(BTW, if you read somewhere that the wavefronts in tractrix horns are spherical, while they are plane in exponential horns, that is not true. This is only the assumptions made when developing the equations. The shape is something like flattened spherical caps in both kinds of horns. Hornresp takes this into acount in the model.)

Regarding reactance anulling, the idea is to make the negative reactance of the rear chamber equal to the positive mass reactance of the horn. This way they largely cancel, and the load seen by the driver is mainly resistive in the working range. It is first described by A.L. Thuras in US patent # 2037185.

Bjørn
So, the equations merely chop off the tractrix horn when they make it smaller? I thought that they would make more of a scale model of a full size version, thus preserving the final curve.
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