The Jean-Michel Le Cléac'h’s horns or as I call them La-Horns get a lot of popularity among people who are trying to build horns loaded systems. But as anything else in audio the Morons hear any noise and they has no idea how to associate the noise with anything else, so, instead of sensibly deal with noise they just brainlessly mimic what they do not understand.

The Jean-Michel enthusiasm about the subject is appealing but only to degree. If one have objectives to endless chewing over of the same irrelevant things then Mr. Cléac'h’s view are good playground for it. It similar if you like tomatoes. You love them and you feel that   tomatoes salad is something that you can’t live without them. You decided to grow your own tomatoes and to do so you but, seeds, cultivate seeding lend, buy a tractor, fertilizers, fight with animals and insects, so do who any other tomato-grower would do. What is very important is to understand that you go over all of your agrarian waves because you want to have better tomatoes. In contrary you might get hooked with a perfect geometry and perfect angle of the spikes of your plow. For the next 15 year you are obsessed with angle of the “perfect spike” and behind your new hobby no one, even you, see the smell and taste of tomatoes.

The reason I write this note is an email that I got last night from a person who is trying to build a big horn system and he asked if I suggest him to buy La-horns.  He said that he read all that I expressed about the subject but he still does not get to home believe: to me or to Jean-Michel. I was surprised with shaping of the question like this as I do not see any conflict or rivalry between Jean-Michel and myself. The difference between Jean-Michel and me is in our approach. Jean-Michel approaches subjects of horns as a self-contained entity. He is way more intelligent, educated and much more scientifically minded then me. He is able to dissect the horn theory to the level that I not able to understand. This is fact. Also, it is a fact that I do not find 95% of what Jean-Michel says a relevant to anything that I value in audio. It is not that he is incorrect, in fact I feel that he is very accurate but it is all about a “perfect spike” that has no, or very little relation to the final Sound of Tomato. If we doctors then my view of horns is a health of enter body. A doctor Le Cléac'h look like think that developing the best method to test some kind of Bilirubin in blood is a way of practicing the healthy well-being. It is not that I find that Bilirubin testing is not important but I do find that from a perspective of general medicine it is pretty much irrelevant subject.

I never read Jean-Michel’s view of playback, audio, sound of music at that mater. I am sure they exist but he does not find it worth to expose at least. Without it I have no reference and no context of many of Jean-Michel’s commentaries.  Why for instance I feel that Jean-Michel’s view about playback organization I find are important? Because the La-horn profile in many ways conflict with ideas of about playback organization. Look at the picture.

You see the La-horn profile with two points A and B. From the throat of the horn to the point A the La-horn implements a tractrix profile. Then there is a section from points A to point B that I call “negative opening”.  This negative opening adds SIGNIFICANTLY to the diameter of the horn. Do I consider that negative opening is beneficial for sound? Yes, I do. At HF it is beneficial, event though I did see the idiots make upperbass La-horns. Why in such case I am not convinced that for MF the La-horn is preferable? Because the sonic practical benefit that might or might not come from the La-horn negative opening are in my view well offset by the system design compromisers that negative opening force you to endure. When idiots stick Yellow Drivers in 150Hz La-horn and use it as full-range channels then I do not talk about negative opening advantages/disadvantages as this setup is idiotic anyhow. In context of multichannel installation   I would only think about the La-profile disadvantage. It might be different if somebody would think about the whole acoustic system setup with La-horn employed. However, no one does it. Jean-Michel draw endless recommendations for big La-profile with ported bass driver at the bottom and the folks who sell La-profiles juts sell individual horns. I did not see the La-profile to be tested and challenged at any installation that I would find offensive or interesting.

It would be a good idea for somebody to try come up with a 5-6 channels when the channels atop would have max La-horn negative opening and gradually to decries the negative opening as the frequency goes down. To make all of it work sonically, make the frame and horn arrangement that it would look attractively would be a very interesting and challenging task. I think this is what Jean-Michel need to do in order to get any credibility for his La-horn profile. Until I see this attempt is undertaken I would insist that I see no deferens between Tractrix and La-horn but find that Tractrix has a lot of real-estate advantages.

Here is a good illustration for people who do not get it why La-profile is suck a damn idea with lower then MF channels. There is a guy in AU who makes the La-profile horns from some kind of plasmas and sell horns separately, not organized into complete installations.  The people buy into it and here is what they have:

http://killerdac.com/forum/index.php?topic=60.msg5561#msg5561

Pay attention that the upper-bass horn in this installation has in that room and in those frequencies absolutely no benefit from La-horn negative opening. In fact the negative opening act as HUGE impediment as it waste a lot of very needed in this configuration vertical and horizontal space.  The owner is not expressed person in the subject and he apparently followed the advice or instance of the horn maker. There is nothing wrong in negative opening but it not suppose to be brainless  demagogy the has no relativity to practicality. Read my notes in the provided link and you will get the idea why.

T3GGG wrote:

Romy, what is your thought on using a Tractrix flare on a Midbass horn, Fc 140HZ then maybe a Le Cleah horn above, say 400hz. To me this looks on paper to be the best of both worlds and avoids the 1metre plus midbass Le Cleac'h horn. I am putting together a set up such as this ATM.

Jean-Michel posted a reply in response to my commentary:

http://www.diyaudio.com/forums/multi-way/140190-jean-michel-lecleach-horns-109.html

Jean-Michel Le Cléac'h wrote:

Hello, Romy is totally wrong on that. ( a parte: I hypothesize that Romy's sentence: "why I don't not like Le Cléac'h (La) horns " doesn't find it's origin in any theorical nor technical consideration... please note that one of Romy's reproach against me is that, in his not humble opinion, I don't share enough my own philosophical considerations about what a good sound should be nor I share enough my own ideas about the proper setting up of a complete audio system... ) At high frequency, the waves takes off from the wall of the horn at a shorter distance from the throat than for the lower frequencies, therefore, at HF the roll-back mouth has no effect. At low frequency, the wavefronts leaves the wall of the horn at a large distance from the throat. with an unbaffled tractrix horn this means that the low frequency waves will be partly reflected at the edge of the mouth. Give a look to: http://www.diyaudio.com/forums/attac...s-rollback.png You can see the effect of the reflected waves on the half upper part of the polar graph corresponding to a truncated Le Cléac'h horn. Then, you can see in the lower half of the graph the increased smoothness of the polar graph of the "complete roll-back" Le Cléac'h horn . Then there is the problem of the integration with the bass channel and with the highs. I don't think that the eventual integration problems associated with the increased diameter of the Le Cleac'h horn are of the same importance level than the benefits of the reduction of the reflected and diffracted waves at the mouth. Best regards from Paris, France Jean-Michel Le Cléac'h

Of cause I very much disagree with his concussions. If we accept the Jean-Michel’s assumption that anything beside pressure travels(!) physically across a horn then frequency while they take off from the walls of the horn obey the rules of diffraction - or  bending themselves to the region of geometrical shadow. At HF the bending is “too violent” as the HF slide of the age of the horn, here is what the La-profile works very good providing a smooth transition to decaying HF. BTW, if you look at the shape of my “Water Drop” tweeter then it will be the same La-Profile with negative opening only extended at full 190 degree. BTW, the constant directivity horns are built in the very same way, introducing diffraction edges and they work only at HF.

At LF the wavelength becomes too long and the negative opening not even being recognized. From my photography time I remember that diffraction increases as the diameter of boundary approaches the wavelength. For 2000kH-3000kH and the wavelength of 4 -6 inches the extra 2-4” of La-profile negative opening is working fine. But at 100Hz and wavelength of 135 inch the 2-4” of La-profile negative opening are negligible. You do not need to have special knowledge but just a common sense to understand that as frequency drops the effectiveness of the La-profile negative opening drops as well. BTW as 40Hz and with much more longer wavelength the edge of the horn has no difference at all…

Sure, in response to it the scientific-minded Jean-Michel posts the graph that demonstrates that La-profile at LF has “increased smoothness of the polar graph”. Well, what Jean-Michel forgets however that at LF is not negative opening of his La-profile begin to work but the fact the he has larger baffle around his horn/ If you remember in 30s WE, Klangfilm and other did the same by increasing the forward LF output and smoothing the of-axis response by building small open baffles around the horn mouth.  There is nothing wrong with that approach (for LF only) but you pay by using larger mouths per each channels, larger then it is necessary for given cut off rate.

So, to have a graph is one thing but to interpret the true applied meaning of the graph is a bit other thing. A mouth of horn does act at LF baffle. So, if one wants to do the comparative graph then the max diameters of Tartaric and La-profile hors need to be identical.  I hope everyone understand that it happens then La-profile will have a good half-octave less in profile rate.

Now is the elephant in the room: “I don't think that the eventual integration problems associated with the increased diameter of the Le Cleac'h horn are of the same importance level than the benefits of the reduction of the reflected and diffracted waves at the mouth.” The integration problems associated with the increased diameter is a HUGE problem, really HUGE and if Mr. Le Cléac'h do not spend time to collect graphs, build theories but play with practically of playback then he would not deny it.  The reduction of the reflected and diffracted waves at the mouth is good but in my estimation it is way less important, not to mention that it work ONLY at HF. I personally feel that randomizing mouth edge is way more effective then negative opening and it takes no extra toll of the size of individual channel.