Jean Michel on LeCleac'h horns

[sqlkev]

Originally posted by revintage


To work well from ca 200hz the horns will need to to be almost 100*100cm ! If you mount them against the sidewalls you can probaly slice at least 30cm off from the "wall-side" of the horns. Attached is an image of a Swedish system with sidewallmounted Lowthers working from 150hz up.

can't possibly mount them against the walls
the width of my room is about 18ft wide

the square lecleach horn is an interesting approach
is there a page with more details on how to make such horn??



soongsc,
can you tell us which is which?
so these were real measurements? which driver did you use on those horn/waveguide??

[soongsc]

Originally posted by tinitus



That I dont understand

Hard to see what is what in your measurements

In the Geddes thread, I started out with doing a large elliptic horn/guide with OS expansion throat but with hyperbolic lip, then a small axisymmetric one with OS expansion throat and hyperbolic lip, last was using an OS expansion throat with LeCleach expansion lip. Hard to explain without getting into too much detail drawings. But the original idea was to find a compromise between CD and HOMs without using foam, and it seemed not one simple curve can accomplish this. So I'm using blends of curvature to see what is optimum for a specific size and driver.
I was showing the measurements of the three in the order putting the last made horn/guide first and the first made last. All cover 45 deg in 7.5 deg increments.

[angeloitacare]

sqlkev

see these two homepages


http://collignon.chez-alice.fr/PAVILLON.htm

http://ndaviden.club.fr/pavillon/fab...rication1.html

I used to listen a 2 inch compression driver on a large Avant Garde modified tractrix horn (with a throat adapter) and it was excellent, even if the Le Cléac'h horn succeed in giving a better 3D sound image.

Jean Michel

some time ago i made a tractrix horn with 25" ( 60cm ) mouth diameter, ( see picture below ) and tested it with the Radian 950Pb, crossing quit low, at 300hz/12db. Performance was tremendous, despite many say, to use a horn driver below Fs increases distortion dramatically. I didn't hear this.

I also agree on your observation, that spacial perception with LeCleac'h horn is excellent, better than with tractrix horns. I would wonder, how comes......

i am curious to know your listening impressions of the setup, you will be listening this weekend.

regarding horn driver for midbass duty:

do you know this

Klangfilm - Siemens 6S ELA 3272 / T8 vintage driver ? ( see last post ) ?

http://www.audiovoice-acoustics.com/...hp?t=66&page=5

what is remarkable, is that it uses a paper cone, and is similarly built like the RCA field coil 1428. It is not expensive, when
( rarely ) offered at ebay. I would wonder how it sounds.

Angelo

[limono]

This is Azura 204 Hz Le Cleach horn on the top of a K-Horn (lowther Dx4). 10.5 ' wall to wall. And a small 550 Hz behind it. Room is to small for such setup therefore I sold Lowther and now use Azura as a low mid horn on the floor untill I build proper midbass. I stucked temporarily Tad Tm 1201 to see what it does (it starts to turn in at 300hz) Nothing is optimized (as usual but I'm telling you that midbass, low mid horn is essential for horn playback.
The question would be if I get the same spatial,relaxed presentation with 80 Hz Hypex (0.7 quarter space) horn with 7" throat in a 80-500hz range??

[soongsc]

Originally posted by soongsc
After finishing some draft measurements of the horn/guide with the LeCleach type expansion with OS type diffraction throat, I though it would be interesting to look at all three horn/guide measurements together. Last made is on top.

It's going to be interesting trimming the last one a bit.

Contour comparison of the last two horn/guides. Shallow contour is top measured curve.

Now, if I actually curled the lip back, what change can I expect?

[tinitus]

Originally posted by soongsc


Now, if I actually curled the lip back, what change can I expect?

Well, Jean Michell has previously said that the main differense in his horns really are the curved mouth, and is what works effectively, the rest should be pretty ordinary stuff

But it seems that you change both length and curvature as well, which could be an issue

This cheap waveguide below ought to be easy to modify with throath smoothing and curved mouth, or at least smooth transition to baffle
Might even be used with small fullrange

[soongsc]

Originally posted by tinitus



Well, Jean Michell has previously said that the main differense in his horns really are the curved mouth, and is what works effectively, the rest should be pretty ordinary stuff

But it seems that you change both length and curvature as well, which could be an issue

This cheap waveguide below ought to be easy to modify with throath smoothing and curved mouth, or at least smooth transition to baffle
Might even be used with small fullrange

Yes, and I am interested in understanding how it effects sound and how we can visualize it through various tests and sims. But first I will spend more time to obtain s specific dispersion pattern that is sort of in between a LeCleach horn and an OS wave guide.

The reason why I change both length and curve is to see what can be accomplished in a fixed form factor. But more important is that although I show only the latter half of the horn/guide for dispersion study, the other half to the diagram is also different which effects other aspects of performance. Notice change in notch shape and location in the measured curves.

The problems I think using full range in horn/guides is that the radiation pattern changes throughout the frequency, thus causing a more complicated wave front, when coupled with a horn/guide, can cause additional coloration to the sound.

Traditionally, people consider drivers and horn/guide seperately, I think a horn/guide should be designed for a specific driver only for optimum performance.

[Jmmlc]

Hello Angelo,

Originally posted by angeloitacare
The best i have come up until now is my actual configuration, using in the midrange a LeCleac'h horn, and Vitavox S2 driver. While it does reproduce most music incredibly well, beeing it a real pleasure and relaxing, to spend time, listening to music, there are other things, that i wish, it would do better. Namely voices, specially female voices, have the tendency, sometimes to sound irritating...

Ronny Weissman uses quite the same set up as you: a Vitavox S2 compression driver mounted on a Le Cléac'h horn built by Marco Henry (Musique Concrète). Please read,

http://goodsoundclub.com/Forums/Show...stID=4593#4593

Few things he says about the high frequencies may be related to some characteristics of the driver.


For my part I only keep the best of his message:
"the sound is fantastic. It is the very stringy cellos with appropriate dynamics, vocals have plenty of subtlety, I really like the sound."

Best regards from Paris.

Jean-Michel Le Cléac'h
[

[Jmmlc]

Hello,

According to Earl Geddes the production of HOMs is related to the derivative of the profile of the waveguide (or horn) and more precisely to the second derivative.

You'll find in attached file compared curves for the OS waveguide and a Le Cléac'h horn showing along the axial distance, the evolution of the first and second derivative of the slope angle of the profile versus the curvilinear distance to throat.

As we can see both 1st and 2nd derivative have greater absolute maximum values near the throat with the OS waveguide when for the Le Cléac'h it is at the mouth.

For what its worth... ;-)

Best regards from Paris, France

Jean-Michel Le Cléac'h

[bear]

J-M,

Been following along with this thread.

I am unsure of some of the things I am seeing and reading.

Regarding a "lip" or "radius" that extends past the point of being perpendicular to the main axis of the horn...

Are you saying that the lip of the horn is best terminated by a large fat lip of considerable size? Did I see a curve where the outer edge of the lip is brought all the way back around to the rear of the horn?

If this is correct, what role does are area that intuitively appears to be unrelated physically to the wave that is launched have?

I think I am seeing that there is a suggestion that terminating the horn to a flat large ("infinite"?) baffle has benefits... are we talking after a curve/radius of some dimension has reached the point of being tangent to the plane that is perpendicular to the main horn axis? Does a larger flat baffle "work" with a "lip" that extends back past this plane (that being the "front of the mouth" where the curving horn mouth meets it)?

And, are we then saying that almost any horn expansion might then benefit from an arbitrary "lip" of sufficient dimension? And, then what is the relationship between the "lip" dimension and frequency/wavelength?

Hope I am being clear enough...

_-_-bear