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
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
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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?
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?
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
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
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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
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
Attachments
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.
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.
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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.
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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.
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.
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.
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.
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
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I would like to second this suggestion. With a second woofer working below bafflestep, the overall efficiency could be increased to about 103 - 106dB SPL. However this might mean a reworking of the XO, so I don't think Lynn would consider this.
OTOH, I must say that Lynn has me salivating when reading about these speakers. The description of the sound reminds me of the reason I got into this hobby in the first place- the sheer love of music. I just want to sit in front of the system and get carried away. That is what makes music so special. So with or without the extra woofer, this sounds like the kind of system that would make me take a step back from the mad rush that is this interesting hobby, and just spend more time listening to music.
Deon
OTOH, I must say that Lynn has me salivating when reading about these speakers. The description of the sound reminds me of the reason I got into this hobby in the first place- the sheer love of music. I just want to sit in front of the system and get carried away. That is what makes music so special. So with or without the extra woofer, this sounds like the kind of system that would make me take a step back from the mad rush that is this interesting hobby, and just spend more time listening to music.
Deon
Actually, I am considering this, although probably not for myself, since the cabinet would then grow to 9 cubic feet, most likely with dual Altec/GPA 416B's in a side-by-side configuration (same layout as the Altec 9844 and JBL Everest DD66000, except with a free-air horn on top).
Another dual-woofer configuration would use one or two open-back boxes filled with dense Bonded Logic UltraTouch filling, which changes the bass radiation pattern to a quasi-cardioid. These have interesting properties midway between pure dipoles and closed boxes; they are much more efficient than dipoles, since the deep bass cancellation is only 3~6 dB compared to the 20 dB loss of a pure dipole, which in turn would allow a second (bass-fill) woofer to offset the losses of the first (cardioid) woofer. When I visit Gary Pimm in a few weeks time, I'll discuss how the math works on these things, and what kind of EQ a dual-15-woofer configuration would require (taking into account the floor image as part of the radiation load).
The first thing is to build my own personal pair of the system described in previous posts (which is up and running, but is not in my house) and keep fine-tuning it. It's about 90~95% there.
The bass cabinet for the single Altec/GPA 416B-Alnico has a slot vent on the floor, the same trick I used on the Ariel to extend the deep bass through mirror-image floor coupling. The front face is slanted 22~30 degrees, to match the aim point of the AH425 on top of it, with small angled side panels, which decrease diffraction on the woofer panel. The width of the bass cabinet is 25"; any narrower, and the midbass becomes too thin. The 25" width sounds about right; I can see why traditional cabinets from the 1950's used widths like these.
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Can someone point out a post or page number that discusses how the box volume and port size were determined? I have run the 416B T/S specs through WinISD using a 4.5 cubic foot box size, but I'm not sure that my results are what were intended. Also, is the slot for the woofer acting as a "variovent", or is it a port with stuffing? (Or maybe that is a distinction without a difference?)
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Lynn, I have a question concerning low bass. Do you think these speakers will work better with say a high-pass at about 50Hz - 60Hz and good subs like the Rhythmic Audio motional-feedback units. This will relieve the mid-bass units from low bass, with possibly better midrange. The XO could maybe be higher, say 70Hz - 80Hz, but I have read a number of people who say this is too high, and it interferes with the low-mids. What are your thoughts?
Thanks,
Deon
Thanks,
Deon
I'm not disagreeing with that. But when referring specifically to the Rhythmic Audio subs with their motional feedback, they will be better in the bass than just about any non-assisted woofer. And I still contend that relieving the midbass from frequencies below circa 60Hz, which is below the area where tone is developed, will have benefits higher up. JMHO. YMMV.
Deon
Deon