Victórios new LeCleac'h horns

[angeloitacare]

hi

Victório received today his new LeCleac'h horns. Some comments of his listening impressions at my forum

[Norris Wilson]

These horns look really nice.

I assume by the looks that they have been constructed using MDF and turned on a lathe?

It is to bad that the LeCleac'h horns are not offered in an elliptical shape. Offering a horizontal dispersion of 90 degrees and vertical dispersion of 40, or no more than 50 degrees.

NW

[sqlkev]

that's beautiful...
how did you acquire a set of those??

[Jmmlc]

Hello Norris,

Yes, that's a bit sad that nobody ever built Le Cléac'h horns having a low height/width ratio.

But they'll be quite difficult to build as you can judge by the following 3D views:

Le Cléac'h elliptical with low HF directivity :
http://www.diyaudio.com/forums/attac...amp=1212759567

quasi Iwta / JMLC method
http://www.diyaudio.com/forums/attac...amp=1212760839

Le Cléac'h constant horizontal directivity
http://www.diyaudio.com/forums/attac...amp=1212761603

Best regards from Paris, France

Jean-MIchel Le Cléac'h

Originally posted by Norris Wilson
These horns look really nice.


It is to bad that the LeCleac'h horns are not offered in an elliptical shape. Offering a horizontal dispersion of 90 degrees and vertical dispersion of 40, or no more than 50 degrees.

NW

[angeloitacare]

hi Norris

i know only 3 manufacturers that make elliptical horns. It is quit difficult to make them . One is Haigner from Austria:

http://www.theaudioeagle.com/columns/column03.html

I have no CNC router, i use a big and small lathe, to make my horns, therefore i am not able to make them elliptical.

On this topic at my forum and on my blog i show step by step, how they are build. It is quit a time consuming task.


Jean Michel

is the small angle and aperture of the horn at the throat not a major reason for horn honk ? the faster the horn opens, the bigger the angle, the shorter the horn is, less is honk ?

Angelo

[Jmmlc]

Hello Angelo,

Horns presenting an efficient loading of the loudspeaker near their low cut-off lead to a high pressure level at the throat (or in the slots of the phase plug in the case of a compression driver). In pro use when this pressure level is more than 120dB then the air is no more elastically linear and some second order distorsion occurs.
As you know second order may be over 5% to be faintly audible. I doubt if any audible effect due to non linearity of air at the horn throat can be audible in Hifi use... This is not a source of honkiness.

The false idea (IMHO) that long horns lead to honkiness came from a famous paper in JAES Vol. 44 N°1-2, 1996 january-february:
"The sound of midrange horns for studio monitors."by
Keith R. Holland, Frank J. Fahy and Philip R. Newell

a conclusion of which was that to overcome honkiness a horn should be short. Please note that at this time, not too ancient, nearly not attention was taken to properly terminate the mouth of any commercial horns.
But one interest of that paper was to point that the 2 horns for which no "horn sound" could be heard (one large multicellular Altec horn and a medium size axisymetrical horn) were the ones having the least reflected waves from mouth to throat.

IMHO distortion of most horns cannot explain honkiness. Honkiness is more related to the behaviour of a horn to avoid reflections from mouth to throat (and the subsequent appearing of artefacts on the pulse response).

Also, near cut-off frequency most horns present a huge rise in the group delay. This is due to the reactance of the horn near the cut-off. This is also a cause of pulse response distortion and may be audible, specially in the band 300 to 4000Hz. You can surely imagine the fundamental of a musical notes arriving later than its firsts harmonics... While this is a source of bad sound I don't call "honkiness" this effect and it can be easily overcome using an electrical crossover frequency an octave or more above the cut-off frequency.

Best regards from Paris, France

Jean-Michel Le Cléac'h

Originally posted by angeloitacare
hi Norris

i know only 3 manufacturers that make elliptical horns. It is quit difficult to make them . One is Haigner from Austria:

http://www.theaudioeagle.com/columns/column03.html

I have no CNC router, i use a big and small lathe, to make my horns, therefore i am not able to make them elliptical.

On this topic at my forum and on my blog i show step by step, how they are build. It is quit a time consuming task.


Jean Michel

is the small angle and aperture of the horn at the throat not a major reason for horn honk ? the faster the horn opens, the bigger the angle, the shorter the horn is, less is honk ?

Angelo

[MiWi]

Hi guys.
I can tell you, that is very time- and money-consuming to build elliptical horns.
Either you make each one on a CNC or you pain yourself with building a mold.
I did it the second way and cast elliptical horns from some kind of special concrete:




(appr. 70cm wide and 50cm tall, 43cm long and 100 pounds each without driver )

I´ve had round horns before, but the elliptical has some advantages.
Wider horizontal dispersion, less reflections from ceiling and floor.

Best regards, Michael

[dnewma04]

Very impressive construction, there. They look outstanding. Do you have documentation on the build process?

[Jmmlc]

Hello Michael,

Your horns look beautiful.

The only questionable thing I can see is that you just applied some strain ratio to the initial circular section perpendicular to the axis in order to make it elliptical.

But doing this, as the section is still laying inside a plane orthogonal to the axis, the curved length of the vertical and the horizontal axial profiles are not the same. and the perimeter of that section is no more the locus of a single wavefront border. Even we cannot evaluate anymore what is the expansion law of the area of the wavefronts inside the horn.

This is surely not the most perfect method to design a horn having a low height/width ratio starting from an initial round horn...

The shapes I shown in message
http://www.diyaudio.com/forums/showt...10#post1608110
like this quasi-Iwata doesn't have this problem.

Best regards from Paris, France

Jean-Michel Le Cléac'h

Originally posted by MiWi
Hi guys.
I did it the second way and cast elliptical horns from some kind of special concrete:

[TomatoBangBang]

Originally posted by Jmmlc
Hello Norris,

Yes, that's a bit sad that nobody ever built Le Cléac'h horns having a low height/width ratio.

But they'll be quite difficult to build as you can judge by the following 3D views:

Le Cléac'h elliptical with low HF directivity :
http://www.diyaudio.com/forums/attac...amp=1212759567

quasi Iwta / JMLC method
http://www.diyaudio.com/forums/attac...amp=1212760839

Le Cléac'h constant horizontal directivity
http://www.diyaudio.com/forums/attac...amp=1212761603

Best regards from Paris, France

Jean-MIchel Le Cléac'h

Hello Jean Michel

What are the equations of the Le Cléac'h elliptical and constant horizontal directivity ?

Thanx