First, I don't think that this subject should be here. It has nothing to do with what others are talking about - tubes, subjective perceptions, etc. It should be a new thread in itself.
The spider is stiff to prevent VC rubs. It is far more effective at that than the surround. A soft spider will need a large gap and hence reduced BL - not good. So the spider is virtually always about 10 x stiffer than the surround. This means that the surround has virtually no effect in the frequency range where the TS parameters are measured. A speaker can be, and have been, made with no surround at all, but this has not been very beneficial.
Up until the first edge resonance, the cone can be thought of as having a free edge because the surround is so soft. The first thing that happens in a cone is that this "free" edge begins to have a greater amplitude than the rest and, in general this causes a rise in the axial SPL. Then this amplitude causes the surround to go into resonance in exact ant-phase and we often find a hole in the response. The surround is the single most important aspect of controlling this peak-hole effect and from what I have seen, a pleated and well damped surround has the best effect - i.e. smoothest response (not that measurements mean anything mind you.)
I know of no woofer that is usable through this edge resonance (it is never smooth enough to be useful), but its effect is critical to the crossover design since it is seldom far enough away to be ignored. This is one reason why "named" crossovers (like Bessel, LR) never work quite as nice in reality as they do on paper.
The spider is stiff to prevent VC rubs. It is far more effective at that than the surround. A soft spider will need a large gap and hence reduced BL - not good. So the spider is virtually always about 10 x stiffer than the surround. This means that the surround has virtually no effect in the frequency range where the TS parameters are measured. A speaker can be, and have been, made with no surround at all, but this has not been very beneficial.
Up until the first edge resonance, the cone can be thought of as having a free edge because the surround is so soft. The first thing that happens in a cone is that this "free" edge begins to have a greater amplitude than the rest and, in general this causes a rise in the axial SPL. Then this amplitude causes the surround to go into resonance in exact ant-phase and we often find a hole in the response. The surround is the single most important aspect of controlling this peak-hole effect and from what I have seen, a pleated and well damped surround has the best effect - i.e. smoothest response (not that measurements mean anything mind you.)
I know of no woofer that is usable through this edge resonance (it is never smooth enough to be useful), but its effect is critical to the crossover design since it is seldom far enough away to be ignored. This is one reason why "named" crossovers (like Bessel, LR) never work quite as nice in reality as they do on paper.
Funny, I was discussing this very thing recently to another.
The "hole" portion is just the surround's structure moving opposite to the peak generated by the outer edge of the cone. In other words while the surround may be partially dampening (which it usually doesn't do very well), and more importantly physically masking, the resonant nature of the cone's outer edge - it's also creating a an artifact in the form of anti-phase dip in response so strong that it actually creates a net null in a reasonably predictable narrow bandwidth. What's more, depending on the structure - the null changes with directivity.
The edge resonance for a given driver often surpasses any other portion of the cone, even with most surrounds, in amplitude/loudness starting at about an octave below the surround "resonance". But at 1 meter this doesn't show up, move further in toward the driver and things change..
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Depending on the surround material and construction method and shape the surround can add an equal or greater restorative force as the spider. It has a lot to do with the spider diameter vs surround diameter and surround material. The spiders are almost all made of cloth and phenolic resin and the differences are created with fold depths and number of rolls and also the amount of phenolic resin applied. Some of the rubber surrounds are actually very stiff and have terrible damping properties, most of the energy is reflected back down the cone when it reaches the cone surround junction. There are no good generalities, they don't hold up well unless comparing like type speakers.
What is the Xmax of a genuine Alte 416 8A ? In U frame damped at the rear for Something between OB & Cardioid ? (in the idea than an Onken is difficult in an universal design because the low end needs to be setuped in relation to the room?)
Could it be possible to play this driver (416 8Abetween 80 hz/100 hz to 700 hz (its max limit due to its cone lightness and directivity at ??? 30° ? = better than many 15" only usable below 400 hz ? The idea of a 15" in this range is only because less energy storage between the cone and air = better musicality than low diameter driver in this range ?)
And if a dedicated amp for this driver (OT ?) some passive EQ between the pre and the amp due to the U-Frame loss below 600 hz ? (to stay in the spirit of analog filter in this thread ?)
Could it be possible to play this driver (416 8Abetween 80 hz/100 hz to 700 hz (its max limit due to its cone lightness and directivity at ??? 30° ? = better than many 15" only usable below 400 hz ? The idea of a 15" in this range is only because less energy storage between the cone and air = better musicality than low diameter driver in this range ?)
And if a dedicated amp for this driver (OT ?) some passive EQ between the pre and the amp due to the U-Frame loss below 600 hz ? (to stay in the spirit of analog filter in this thread ?)
The turboencabulator is a great example. I understand that GE are about to re-release it, it will be interesting to see if it is as reliable as the original.
I spent a bit of time looking through bookmarked youtubes - looking for an example of where:
1. you could hear the acoustic of the room from a source (the youtuber) as he talks and you hear the acoustic of the listening space - his listening room (..which is an artifact of listening to a recording, something most people would autonomically disregard within about 30's seconds upon entering the room the first time), and
2. where you could hear some approximation of large space from the recording - to the point where it pretty much displaces the apparent acoustic of the room.
Note: there are all sorts of problems with the track and instrumental placement (mic'ing, etc..), serious problems with the youtuber's mic. (overload, linearity, etc. - and dig that tilt action that's going on..)., problems with speakers placement, etc.. and of course don't forget that this is a recording of stereo reproduction - and as such the small room acoustic should become an overlay that a normal person would hear. Despite the numerous caveats.. yeah, it largely expresses that difference between 1 & 2 (..to me at least).
The effects of both should be obvious with most listening systems - including headphones.
https://www.youtube.com/watch?v=xEcHRPWnSoA
Please note the relative placement of the speakers in relation to the camcorder/mic and the room.
If you want to hear much better imaging (with an over-damped tonal signature), but NOT with the same level of reproduced envelopment: then try (in multiple uses of that word) listening to his over-loaded LX521 videos.
1. you could hear the acoustic of the room from a source (the youtuber) as he talks and you hear the acoustic of the listening space - his listening room (..which is an artifact of listening to a recording, something most people would autonomically disregard within about 30's seconds upon entering the room the first time), and
2. where you could hear some approximation of large space from the recording - to the point where it pretty much displaces the apparent acoustic of the room.
Note: there are all sorts of problems with the track and instrumental placement (mic'ing, etc..), serious problems with the youtuber's mic. (overload, linearity, etc. - and dig that tilt action that's going on..)., problems with speakers placement, etc.. and of course don't forget that this is a recording of stereo reproduction - and as such the small room acoustic should become an overlay that a normal person would hear. Despite the numerous caveats.. yeah, it largely expresses that difference between 1 & 2 (..to me at least).
The effects of both should be obvious with most listening systems - including headphones.
https://www.youtube.com/watch?v=xEcHRPWnSoA
Please note the relative placement of the speakers in relation to the camcorder/mic and the room.
If you want to hear much better imaging (with an over-damped tonal signature), but NOT with the same level of reproduced envelopment: then try (in multiple uses of that word) listening to his over-loaded LX521 videos.
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Reaching there, a little, are we?
Maybe it IS always possible - everywhere but in YOUR room, Earl.
I blame that alien speaker technology you picked up from Area 51. It's not really suitable for human ears. Probably the cause of so many of your troubles.
...... 
I'm the only one who saw from the Inside the 51 zone
... while I was Lucky because no krytonit 
I like you both guys : Mr Earl because we need also to talk more than simple XOs (in fact I believe the forum needs a serious theoric thread about drivers : physic, damping of material, what is a room, etc !) and Pano for also :great empiric & concrete - & parisian- experience... and he saw also a lot of systems (even the much biger parisians'
- do you know Mr Hiraga ?))I trust you both ! (with all my humble from a siple entusiast !)
If only we could have a more afordable "good horn with foam" above a 500 hz to 700 hz to cross 12" or 15" drivers????
I bet for an Eminence Delta 2 : 74g (stiff enough to climb to 700 hz ?), bottom free of reflection, as we don't speak any more for mid-bass about low mms around 10 g to 20 g with 8" like a http://www.supravox.fr/anglais/haut_parleurs/215_GMF.htm, why not follow Dr Gedle protocol where low energy storage is choosed instead lower Sd and Mms ? Ok on topic with the GPA 416 8A ! (I like the Eminence Delta 2 just because the low mms in relation to Xmax + Sd + bottom of the cone free of obstructions .... in a Fr between ? >80hz to 700 hz in the spirit of around 600/700 hz like the Altec 4168A is planned in some scenari but here in vented with lower FR ! -believe just by earing some system it's an error to follow with a mono driver Onken enclosure - if choosed-) !
Lynn Olson's room listening seems not common from a point of view of some western people from Europe : cell are often 2.4 m heigth in new flats ! mine, I'm Lucky my listening room is 2.75 m ! Lynn's one is higher : it helps !)
I liked the idea of Juhazi member to take the idea of an OB 12" driver just for the mid-bass in his own design (very well documented here in Diyaudio) ! Question is if a CD driver+ horn is keeped : how to solve the lobying between around the 700 hz transition of the 2 drivers with their different fastness ? (12" cone driver versus 2" Compression driver + horn) ? crossover low order ?
If high Sd with bad high directivity but choosed because low energy storage between the cone and air for Fr above 400 hz with 15" drivers (Summa!) : how to solve the phase and different transcients (the same if phase is solved ? I think about physical arrengement like some FIR soft EQ)
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Enjoyable sound - Philco 91
In my last post, I promised some examples of unconventional (at least by "high-end" standards) sound reproduction example that nevertheless are quite satisfying. Here is an example given to me by a co-worker over 30 years ago who found it in his grandparent's attic in Kansas. It is a Philco model 91 "Baby Grand" cathedral radio, first produced in 1932:
This was their high-end model, and has nine tubes. The audio power amplifier is push-pull type 42 pentodes (same as the 6F6), driven through a transformer by a single type 37 low-mu triode. The speaker is about 7" in diameter and is electro-dynamic. Other than having some capacitors and tubes replaced, it is completely original. Although this style of radio was called a "midget", it is rather large: 16" wide, 11" deep, and 18 1/2 inches tall.
Why include this example on Lynn's "Beyond the Ariel" thread? Well, technically, it does use a push-pull amplifier with no feedback and a modified open-baffle cabinet. However, I prize it for its unique sound - a bit boomy, but otherwise rich and warm. It makes music and voices sound really appealing - in fact it is a sound that would be impossible to buy in new equipment today.
There is not much interesting on AM radio today: mainly religious stations, hate radio, and country music (not my style). However there is a station I can get that plays "oldies" including some going back to the '30s and '40s. It is these vintage songs that really work well with the sonics of this radio. The sound reproduction systems of that era really took advantage of the technology of the time: crooners singing into ribbon microphones, and 78 rpm records that matched the limited high-frequency capability of AM radio of the time (5 to 8KHz). Despite these limitations, the experience is really enjoyable. Contrast this to the radio in my new car, when listening to regular AM radio stations, has a severe HF cutoff (it sounds like 3-4KHz), or, if in range, AM HD radio that has wide bandwidth, but obvious digital artifacts - quite unpleasant.
Lynn's new system will undoubtedly go far beyond what this table radio can do. But I'm sure there is a little bit of this radio in it - the part that makes the experience enjoyable.
- John Atwood
In my last post, I promised some examples of unconventional (at least by "high-end" standards) sound reproduction example that nevertheless are quite satisfying. Here is an example given to me by a co-worker over 30 years ago who found it in his grandparent's attic in Kansas. It is a Philco model 91 "Baby Grand" cathedral radio, first produced in 1932:
This was their high-end model, and has nine tubes. The audio power amplifier is push-pull type 42 pentodes (same as the 6F6), driven through a transformer by a single type 37 low-mu triode. The speaker is about 7" in diameter and is electro-dynamic. Other than having some capacitors and tubes replaced, it is completely original. Although this style of radio was called a "midget", it is rather large: 16" wide, 11" deep, and 18 1/2 inches tall.
Why include this example on Lynn's "Beyond the Ariel" thread? Well, technically, it does use a push-pull amplifier with no feedback and a modified open-baffle cabinet. However, I prize it for its unique sound - a bit boomy, but otherwise rich and warm. It makes music and voices sound really appealing - in fact it is a sound that would be impossible to buy in new equipment today.
There is not much interesting on AM radio today: mainly religious stations, hate radio, and country music (not my style). However there is a station I can get that plays "oldies" including some going back to the '30s and '40s. It is these vintage songs that really work well with the sonics of this radio. The sound reproduction systems of that era really took advantage of the technology of the time: crooners singing into ribbon microphones, and 78 rpm records that matched the limited high-frequency capability of AM radio of the time (5 to 8KHz). Despite these limitations, the experience is really enjoyable. Contrast this to the radio in my new car, when listening to regular AM radio stations, has a severe HF cutoff (it sounds like 3-4KHz), or, if in range, AM HD radio that has wide bandwidth, but obvious digital artifacts - quite unpleasant.
Lynn's new system will undoubtedly go far beyond what this table radio can do. But I'm sure there is a little bit of this radio in it - the part that makes the experience enjoyable.
- John Atwood
During my brief stint as Technical Editor for Vacuum Tube Valley, I paid a visit to the editor and publisher, Charlie Kittleson (sadly no longer with us). His place in California was chock-full of antique stuff in good working order, including a late-Thirties guitar amp. Charlie was a pretty decent electric-guitar player and gave Gary Pimm and I an impromptu concert showing what different amps from different eras sounded like.
That's when I realized what Charlie and John Atwood were going on about ... man, that old stuff had TONE ... and was really clear, with a remarkable shimmering bell-like quality. Nothing like the fat, slow jukebox sound of the Fifties. The Thirties gear had a different esthetic, and most audiophiles have never heard it. Altec is one of the few companies that carried that sound forward ... clear, with bright, lively harmonics. The Tannoy is a different ... well, English ... sound, and the German Klangfilm is different again.
There are good technical reasons for this, of course. No-feedback architecture. Different caps, and the occasional transformer coupling. The larger vacuum tubes have a cleaner spectral structure than the 12A*7 miniature tubes of the Fifties. Rather than bandwidth, the speakers are optimized for clarity and natural-sounding tonal qualities. People listened to a lot more live, acoustic music back then, and expected a radio to sound like live music. Amplified concerts, or amplified music in general, were pretty rare.
By the Fifties, wideband LP's, FM radio, and mag-track movies had become widespread, and the emphasis in the "High Fidelity" market changed to a wide dynamic range and a considerably wider bandwidth in the playback system. The goalposts had moved. "Good Tone", as such, was no longer mentioned in product literature, and customers expected a more dramatic, flashier kind of sound. The first hi-fi shows appeared on the scene, and Playboy magazine, believe it or not, had a "lifestyle" section devoted to the latest hifi gear.
This trend went into hyperdrive when high-powered transistor amps like the Crown DC300A and the Phase Linear 700 were used to power the first rock concerts. Tone went out the window, and slam-bang power was the thing. For most consumers, it still is.
Hearing Charlie's vintage gear was an incentive to find out why it sounded that way, and what had been lost by the Fifties. A well-done DHT amplifier (or an amp done in Thirties-vintage style), along with sympathetic loudspeakers, is a window into a different kind of sound, far away from the mainstream of high-end audio. Once you get on board, it's hard to listen to mainstream high-end gear any more. It sounds dry, airless, and mechanical.
That's when I realized what Charlie and John Atwood were going on about ... man, that old stuff had TONE ... and was really clear, with a remarkable shimmering bell-like quality. Nothing like the fat, slow jukebox sound of the Fifties. The Thirties gear had a different esthetic, and most audiophiles have never heard it. Altec is one of the few companies that carried that sound forward ... clear, with bright, lively harmonics. The Tannoy is a different ... well, English ... sound, and the German Klangfilm is different again.
There are good technical reasons for this, of course. No-feedback architecture. Different caps, and the occasional transformer coupling. The larger vacuum tubes have a cleaner spectral structure than the 12A*7 miniature tubes of the Fifties. Rather than bandwidth, the speakers are optimized for clarity and natural-sounding tonal qualities. People listened to a lot more live, acoustic music back then, and expected a radio to sound like live music. Amplified concerts, or amplified music in general, were pretty rare.
By the Fifties, wideband LP's, FM radio, and mag-track movies had become widespread, and the emphasis in the "High Fidelity" market changed to a wide dynamic range and a considerably wider bandwidth in the playback system. The goalposts had moved. "Good Tone", as such, was no longer mentioned in product literature, and customers expected a more dramatic, flashier kind of sound. The first hi-fi shows appeared on the scene, and Playboy magazine, believe it or not, had a "lifestyle" section devoted to the latest hifi gear.
This trend went into hyperdrive when high-powered transistor amps like the Crown DC300A and the Phase Linear 700 were used to power the first rock concerts. Tone went out the window, and slam-bang power was the thing. For most consumers, it still is.
Hearing Charlie's vintage gear was an incentive to find out why it sounded that way, and what had been lost by the Fifties. A well-done DHT amplifier (or an amp done in Thirties-vintage style), along with sympathetic loudspeakers, is a window into a different kind of sound, far away from the mainstream of high-end audio. Once you get on board, it's hard to listen to mainstream high-end gear any more. It sounds dry, airless, and mechanical.
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Imagine this driver, integrated crimped-paper "surround" and paper former with the field coil motor, on an Inlowsound 80 Hz horn.. BUT without the rear chamber - open-baffle:
Wolf von Langa | A1.1500
-but I don't think they are exactly "giving-away" that driver..
Imagine this driver, integrated crimped-paper "surround" and paper former with the field coil motor, on an Inlowsound 80 Hz horn.. BUT without the rear chamber - open-baffle:
Wolf von Langa | A1.1500
-but I don't think they are exactly "giving-away" that driver..
Looks like really good components that one would make in the workshop.
The science in it all, is really very basic in reality. The measurements they post show this but I bet the sound is appealingly good. l like the best old stuff as it just looks so robustly made to do the job, with straight forward good old Newtonian principles and good old and some young ears that unexplainably like it.
It is also good to see Vitavox at a price are still around in the UK. This gear all has its charm, but the sentiment value thing, I just evade on principle. The WAF thing at leasts stops it gettiing out of hand for these antique designs. After all the WAF thing is also often a VFM issue as well as decor and taste
Imagine this driver, integrated crimped-paper "surround" and paper former with the field coil motor, on an Inlowsound 80 Hz horn.. BUT without the rear chamber - open-baffle:
Wolf von Langa | A1.1500
-but I don't think they are exactly "giving-away" that driver..
There are modern field coil Altec 416 made by Chela Audio, however when I was looking into them it was impossible to find any information. From user impressions to a chart with T/S parameters for various coil voltage, or if they were GPA or vintage cones... nothing.
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YES! That was always the thing that scared me away from even considering horn speakers-even hybrid horn speakers, like Gary's. No wonder the audience were all smiles when Gary demoed his system! http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-1356.html
This is wonderful news.
Your comparisons seem to confirm that the AH 425 horns have all the virtues of direct radiators and none of their faults. Though I wish I could have attended the auditioning of Gary’s system last month, it wouldn’t surprise me if many in the audience would have concurred with your observations. This is most welcome and heartening news as I move to complete these BTA speakers.
What would be your first and second choice beryllium dome tweeter to work with the Radian745/AH425?
Not to second guess you or Gary, but how would the sonics and dispersion patterns of those recommended dome tweeters compare to the RAAL Lazy ribbons?
Careful. Re-read those quotes again. The AH425 sounds like a large dome tweeter; it isn't actually a dome tweeter.
In reality, a complementary supertweeter needs to have the same dynamics as the AH425 + large-format compression driver. This is in a completely different league than any soft dome tweeter. The RAAL gets away with it is because it's used at a very high frequency where tonality (and tone color) isn't apparent ... it's also RAAL's most efficient (and dynamic) ribbon at 109 dB/meter or so.
Commenters have suggested several Fostex supertweeters as well as the Beyma TPL-150 series (a modern version of the Heil Air-Motion Transformer). I don't see it as a major problem; the addition of a supertweeter is fairly subtle and the choice of supertweeter has a lot to do with the HF purity of the preceding electronics.
Imagine this driver, integrated crimped-paper "surround" and paper former with the field coil motor, on an Inlowsound 80 Hz horn.. BUT without the rear chamber - open-baffle:
Wolf von Langa | A1.1500
- but I don't think they are exactly "giving-away" that driver..
The glamor of field-coil drivers is interesting (and a little strange). The soft iron core of a field-coil magnet is easier to make than machining Alnico, which leaves the question why they cost more than Alnico.
The rarity and retro-novelty of field-coils must account for the pricing. Yes, they sound different (as you would expect), and there's the convenience of dial-a-BL (magnetic flux) by adjusting the supply voltage. If the heat-sinking is good enough, you can saturate the pole-pieces by forcing in more power to the electromagnet, so there's that.
It's the Twenties and Thirties technology that preceded high-strength permanent magnets. Unlike vacuum tubes, (which require vacuum pumps, special chemicals, and a reasonably clean environment) it would seem that any loudspeaker manufacturer in the world could make field coil loudspeakers. I'm surprised the Chinese haven't jumped on this one. Soft iron components, check (the inner pole piece is already made of soft iron). Winding several hundred turns around the soft-iron magnet, check (if they can wind voice coils, they can wind coils around a field magnet). It's not a big deal to manufacture.
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Hi Lynn,
Here's a glimpse or snippets of field coil driver assembly and petal JMLC round horns, etc:
https://vimeo.com/134687364
Reminds me of 'wall of sound' systems by the Japanese friends of Jean Hiraga that participated in last year's ETF:
http://www.triodefestival.net/uploads/ngrey/Japan Team, 3 systems.pdf
Aesthetics of the speakers on the vid above would divide folks here most likely.. The wood finish reminds me of the 30's table radio John posted though.
@John Atwood
Thanks for your commercial phono design btw. It inspired me to do something similar in diy for the output with a plate choke years ago. Although mine has no local feedback..
Here's a glimpse or snippets of field coil driver assembly and petal JMLC round horns, etc:
https://vimeo.com/134687364
Reminds me of 'wall of sound' systems by the Japanese friends of Jean Hiraga that participated in last year's ETF:
http://www.triodefestival.net/uploads/ngrey/Japan Team, 3 systems.pdf
Aesthetics of the speakers on the vid above would divide folks here most likely.. The wood finish reminds me of the 30's table radio John posted though.
@John Atwood
Thanks for your commercial phono design btw. It inspired me to do something similar in diy for the output with a plate choke years ago. Although mine has no local feedback..
Lynn,
One of the interesting points I get from the posts just quoted is that you don't want a constant directivity horn. There is a big disagreement on this simple factor and different horn topologies. Earl's horns are of the constant directivity type, to me nothing more than a conic section with a wide radius on the edge to overcome what would cause a real noticeable diffraction pattern with any wavelengths that are greater than the horn end dimensions. the reason that wide radius is necessary. On the other hand you have the many exponential and hypex type of horns that have a changing dispersion angle as frequency rises. It is a totally different way to look at the problem. One horn is trying to eliminate the wall reflections by having a very directional pattern and the other idea is allowing a to me more natural process of directivity with frequency. When in a live music situation that is more realistic, the highs are more directional and as the frequency reduces the sound becomes omnidirectional. I personally use very short and wide horns for in home horns, not a longer and narrow type of horn. I think it is a preference of sound type, I think Earl would argue that what is important is the the pattern at crossover is the most important issue and a more controlled pattern so you are listening to mostly first impulse response without the rooms secondary reflections. I personally like when I can walk across a horn up to 90 degrees and barely hear a change in response, that is my preference. It doesn't make one design superior to the other so you do have to be careful in your selection. I don't think many understand how different two horns with the same length and entrance diameter can sound in a room and how much the room itself changes that perception. I don't have the same issue with multiple horns as others have, I'm not locked into the two way systems that attempt to limit the number of crossover networks. I have done three way systems with a dynamic driver for the bottom end and have done large PA type systems with horns all the way down. Every situation is different and there is no one magic solution to this. I think many of the bad PA implementations using horns have soured the use of horns, I don't believe it has to be that way, but that was the conversation for so long that today it is hard to overcome beyond those few who are willing to look with open eyes. Some early designs that were truly meant for PA use have just persisted even when they were terrible from the beginning. Some things that come to mind are the slant plate diffraction lenses used by JBL on extremely narrow small horns and even some of the ring radiators that most find as irritating as a poorly designed Ti dome tweeter. I don't have a problem with some of the old classic devices but don't think they have any inherent advantage over newer devices, I surely wouldn't look for any old Altec or JBL or other drivers thinking that the older models have anything over a newly produced device.
One of the interesting points I get from the posts just quoted is that you don't want a constant directivity horn. There is a big disagreement on this simple factor and different horn topologies. Earl's horns are of the constant directivity type, to me nothing more than a conic section with a wide radius on the edge to overcome what would cause a real noticeable diffraction pattern with any wavelengths that are greater than the horn end dimensions. the reason that wide radius is necessary. On the other hand you have the many exponential and hypex type of horns that have a changing dispersion angle as frequency rises. It is a totally different way to look at the problem. One horn is trying to eliminate the wall reflections by having a very directional pattern and the other idea is allowing a to me more natural process of directivity with frequency. When in a live music situation that is more realistic, the highs are more directional and as the frequency reduces the sound becomes omnidirectional. I personally use very short and wide horns for in home horns, not a longer and narrow type of horn. I think it is a preference of sound type, I think Earl would argue that what is important is the the pattern at crossover is the most important issue and a more controlled pattern so you are listening to mostly first impulse response without the rooms secondary reflections. I personally like when I can walk across a horn up to 90 degrees and barely hear a change in response, that is my preference. It doesn't make one design superior to the other so you do have to be careful in your selection. I don't think many understand how different two horns with the same length and entrance diameter can sound in a room and how much the room itself changes that perception. I don't have the same issue with multiple horns as others have, I'm not locked into the two way systems that attempt to limit the number of crossover networks. I have done three way systems with a dynamic driver for the bottom end and have done large PA type systems with horns all the way down. Every situation is different and there is no one magic solution to this. I think many of the bad PA implementations using horns have soured the use of horns, I don't believe it has to be that way, but that was the conversation for so long that today it is hard to overcome beyond those few who are willing to look with open eyes. Some early designs that were truly meant for PA use have just persisted even when they were terrible from the beginning. Some things that come to mind are the slant plate diffraction lenses used by JBL on extremely narrow small horns and even some of the ring radiators that most find as irritating as a poorly designed Ti dome tweeter. I don't have a problem with some of the old classic devices but don't think they have any inherent advantage over newer devices, I surely wouldn't look for any old Altec or JBL or other drivers thinking that the older models have anything over a newly produced device.