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Old 23rd August 2012, 02:09 AM   #7821
Pano is offline Pano  United States
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OK, so you're saying the Radian 745Neo without super tweeter? The published curves look good, but I'm not sure it would go that high on my multi-cell horns. Might do the trick on Lynn's horns, tho.
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Old 23rd August 2012, 02:37 AM   #7822
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Honestly, start with that then listen. I think you will be impressed.
If you feel it still does not have the air, and clarity you want try some sought of wideband eq reduction of the midrange. However this radian is quite good, it does not have a pronounced midrange bumb, I find that it is this midrange bump that I don't like, making things sound overly nasaly. If you reduce it things start sounding very nice

Last edited by Melon Head; 23rd August 2012 at 02:44 AM.
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Old 23rd August 2012, 03:33 AM   #7823
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Lynn, thanks for your explanation on the relative merits of horn dispersion and associated diffraction.
When I'll eventually see your finished design, I may still want to opt for tractrix though, simply because I can rarely sit down and only listen to music. Typically I will be doing several things while listening. Hence the idea of good dispersion with still good quality fits my situation better than perfect listening at 1 sitting position.
Now, I do wonder: imagine that you would change your lecleach for another horn type of similar size, would you need to change your filter? I would expect so since the energy spread would be different, there would be a different loudness sensation. Comments?
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Old 23rd August 2012, 04:05 AM   #7824
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Just to summarise very briefly. What I have found is that it is more to do with the shape of the frequecy response than the absolute hi frequency extension.
I just recently discovered that most of what you hear that sounds very pleasing occurs below 15kHz and getting that right has more of an impact on how you perceive the sound. I just recently discovered this and it came as a complete surprise.
The surprise came when I heard a speaker not capable of 15 kHz smash my scanspeak setup in overall detail air and clarity

Last edited by Melon Head; 23rd August 2012 at 04:18 AM.
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Old 23rd August 2012, 06:51 AM   #7825
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Hello,

I think that there is some mistake in your idea that a tractrix could possess a better dispersion than a Le Cleach horn. For the same cut-off frequency both of them have nearly the same polar patterns.

See the attached graph which presents the comparison between simulation performed with Hornresp of the polar maps of
a tractrix (upper half of the diagram) and a Le Cléac'h horn (bottom half of the diagram).

An advantage of the Le Cleac'h horn upon the tractrix being smaller diffraction effects at the mouth (in some case that diffraction can give a fake impression of better dispersion though). But I fully agree with Lynn that diffraction is the firts thing to avoid in horns and this is one of the main goals of the Le Cleac'h horn

Best regards from Paris,

Jean-Michel Le Cléac'h


Quote:
Originally Posted by talaerts View Post
Lynn, thanks for your explanation on the relative merits of horn dispersion and associated diffraction.
When I'll eventually see your finished design, I may still want to opt for tractrix though, simply because I can rarely sit down and only listen to music. Typically I will be doing several things while listening. Hence the idea of good dispersion with still good quality fits my situation better than perfect listening at 1 sitting position.
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Old 23rd August 2012, 07:56 AM   #7826
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I pretty much memorized the Newell and Holland book. Of all the horns out there, the only one I could find that met all of the N&H criteria was the LeCleac'h. The custom BEM software written by Bjorn Kolbrek further underlined this, since we looked at other profiles, and most of them had quite noticeable throat diffraction, as well as edge effects at the horn-mouth. The diffraction propagated through the horn and became worse as the wavefront expanded, resulting in narrow spikes in the polar pattern, as well as reflections in the time domain.

Although diffraction has been used in PA horns for decades - for example, the Altec Mantaray and JBL Bi-Radial - those are primarily PA applications, where even coverage of the audience is the primary design requirement. In PA applications, stereo barely exists, since even being a few seats away from the centerline - which applies to most of the audience - destroys the phantom image. This is why theaters use a center speaker, so the dialog does not jump into the left or right speaker.

In domestic listening, the prime seat is on the centerline, with the expectation of somewhat degraded stereo off-center. With careful shading of the polar pattern - this is where a soft-edged LeCleac'h is especially useful - and aiming at a point a foot or two in front of the listener, the image can be preserved reasonably well for off-axis listeners, using intensity/time trading. But even in ideal circumstances, say with true-omni Walsh/MBL drivers, there's a bit of blurring for off-axis listeners.

PA and domestic requirements are radically different, although a lot of the underlying technology is similar. At home, there's a reasonable expectation of high-quality 2-speaker stereo, and if desired, 3, 4, and 5-channel full-surround, with stable images, a realistic impression of space, and freedom from "hifi-like" colorations. "Detenting" of the image space is extremely undesirable in a domestic application, while in PA, it is not even meaningful, since very few members of the audience will sit on the centerline - most will be 10 mSec or even more off-center, which completely prevents any kind of intensity/time trading. This kind of trading only occurs in a fairly small window of 3~5 mSec - beyond that, it falls apart, and the image is very unstable and distorted.

Part of my preference for LeCleac'h versus Tractrix is subjective: some of the local folks here in Denver have tried the different horns with cone drivers, and I preferred the LeCleac'h every time. I see no advantage for the Tractrix; in subjective terms, it sounds flatter, less 3D, and there are hints at times of horn diffraction colorations. But then again, some people like the sound of horn diffraction colorations, with the Altec 511 sectoral horn being the prime example (another horn with a diffraction pinch in the throat).

My tolerance for diffraction, particularly horn diffraction, is very low, so the LeCleac'h just sounds better. But that's me. Other folks love the sound of traditional sectoral horns with an exponential profile - the full horn experience, as it were. I don't think these audiophiles (or music lovers) are dumb or have no taste; they just aren't as bothered by diffraction artifacts as I am. Nothing more, nothing less, and they have the luxury of enjoying old-school as well as modern horns. A traditional Klipschorn is hardly a low-coloration loudspeaker, but they're still a lot of fun to listen to.

I do have a soft spot for Altec multicells. They sound completely different - I mean really different - than the traditional Altec sectoral horns. Look closely at the polar patterns, and the sectorals have the notorious "pattern flip" around 3 kHz, while the multicells have pretty stable patterns over the working range.

The pinnacle of (American) mid-Fifties loudspeaker technology was a custom Klipschorn bass unit with an Altec multicell & 288 compression driver for HF, and an Electro-Voice T350 supertweeter. Alnico magnets throughout, of course, and all-analog and all-tube electronics. I've never heard that setup (well, actually I might have heard it in my childhood, but don't really remember the sound), but that's a pretty nice driver lineup.

Last edited by Lynn Olson; 23rd August 2012 at 08:24 AM.
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Old 23rd August 2012, 08:45 AM   #7827
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FWIW, I run a pair of Altec 288 (16 ohm) and also have a pair of older Radian large format drivers. Love 'em! Altec 416A are my woofers.
I have the odd feeling that large-format compression drivers, a multicell or well-designed LeCleac'h (with exit-angle of the driver as part of the design equation), combined with the Altec/GPA 416 bass unit, might be the destination for many audiophiles who have evolved into music lovers.

This might sound a little gushy, but I can't think of anything else that has the beautiful tone colors of a large-format Altec setup. Big-panel electrostats have comparable resolution and 3D-ness, but tonal beauty and take-your-breath-away musical expressiveness? They try, but don't quite get there.

And 85~89 dB/meter audiophile speakers sound flat and dead once you get used to the sound of high-efficiency speakers. Even the Ariels at their modest 92 dB/meter made it hard to enjoy conventional audiophile speakers that are 3~5 dB less efficient. You just hear more, and it sounds more beautiful. Like direct-heated triodes, you don't go back.

It's about surrendering to the emotional experience, just letting go, no more thinking and analyzing, just allowing yourself to be swept away by the music. Not all audiophiles can do this. I've seen some of them, in my own listening room, hold their arms tightly across their chests, fighting off their emotions. Maybe they didn't like what they heard, but the sound quality was ravishing, far above anything at an audio show, and was certainly affecting me and Karna.

I'm kind of letting the cat out of the bag here, but I design audio equipment so the listener can have a deep emotional experience; the technical parameters are simply a means to an end, for the system to get out of the way.

Last edited by Lynn Olson; 23rd August 2012 at 09:00 AM.
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Old 23rd August 2012, 08:46 AM   #7828
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Over the last two years I have tried and tested the following horns:

JMLC-200 (with 8" regular cone drivers from Lowther and Fostex)
JMLC-200T with JBL2446, Altec 288, Altec 399, TAD 4001)
JMLC-350 same line-up as for 200T
JMLC-400 " "


- and I can honestly say I have never heard a smoother sounding horn profile ever. Colorations and diffraction levels are astonishingly low.
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Old 23rd August 2012, 09:07 AM   #7829
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I couldn't agree more. Frankly, it's satisfying to forget about horn profiles, settle on an exit-angle-matched LeCleac'h, and refine other parts of the loudspeaker. The refining process is greatly simplified by the good nature of the LeCleac'h, which are easy to cross over and don't need a lot of complex equalization.

Thank you very much, JMMLC, for giving us these designs. And thanks also to Bjorn Kolbrek for designing software that let me see inside the horn, and visualize diffraction.
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Old 23rd August 2012, 09:34 AM   #7830
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Quote:
Originally Posted by Lynn Olson View Post
This might sound a little gushy, but I can't think of anything else that has the beautiful tone colors of a large-format Altec setup. Big-panel electrostats have comparable resolution and 3D-ness, but tonal beauty and take-your-breath-away musical expressiveness? They try, but don't quite get there.

And 85~89 dB/meter audiophile speakers sound flat and dead once you get used to the sound of high-efficiency speakers. Even the Ariels at their modest 92 dB/meter made it hard to enjoy conventional audiophile speakers that are 3~5 dB less efficient. You just hear more, and it sounds more beautiful. Like direct-heated triodes, you don't go back.

It's about surrendering to the emotional experience, just letting go, no more thinking and analyzing, just allowing yourself to be swept away by the music. I'm kind of letting the cat out of the bag here, but I design audio equipment so the listener can have a deep emotional experience; the technical parameters are simply a means to an end, for the system to get out of the way.
I got a gut feeling this will be a very special speaker.
The only thing I would do different is use 2 of those Altec woofers per speaker.
I just love the effect of dual high effciency woofers

Last edited by Melon Head; 23rd August 2012 at 09:38 AM.
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