Don Richard Posted July 22, 2014 Share Posted July 22, 2014 If a point source is considered the ideal, how does that lead to beginning with a horn? I see the obvious connection to efficiency, but I really don't see the rest of the argument. If a point source is ideal, then Tom Danley's Synergy horns are an ideal point source loudspeaker. He uses multiple drivers appropriately crossed over and fed into one conical horn. Impulse response is amazing, and they will pass square waves over a wide frequency range. Conventional stacked horn systems that use digital loudspeaker processors can emulate a point source by properly adjusting delays. The phase response of such a properly aligned horn system is far better than so called "single driver" designs. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 23, 2014 Share Posted July 23, 2014 It radiates in 360 degrees? Certainly. Both the EAW KF750 and the Showco Prism are curved point source arrays that can be configured for 360 degree horizontal coverage, and along with upfill and downfill enclosures will approach spherical coverage. Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Chief bonehead Posted July 23, 2014 Klipsch Employees Share Posted July 23, 2014 Wow. Where is mr klipsch's yellow button when you need it?? Experts galore and no common sense in sight......sigh! 1 Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted July 23, 2014 Share Posted July 23, 2014 If I had the perfect point source.......I would load it with the perfect horn... miketn Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 If a point source is considered the ideal... Is a point source really considered the ideal? I'm not sure I subscribe to that premise... An infinitely large point source... Infinitely large point? Isn't that an oxymoron? Points are infinitely small and that's why they radiate a full 360 degrees. I don't want my speakers radiating 360 degrees. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 Wow. Where is mr klipsch's yellow button when you need it?? Experts galore and no common sense in sight......sigh! Coming from the chief bonehead himself! Sorry, couldn't resist For the record, there are many here who would welcome new insights. PWK didn't just throw bs buttons around.....he openly shared the reasons behind his views, and in my opinion that is why he was so valuable to the audio community. I have no problem being labeled an audio idiot, but I have no reason to stop believing what I feel I've learned this far without solid evidence to the contrary. I'm sure many here feel the same way about their ideas too. Why come here to tell us we're stupid when we already know that? I only make bold claims so those smarter than I can reveal the faulty logic. Quote Link to comment Share on other sites More sharing options...
Chris A Posted July 23, 2014 Author Share Posted July 23, 2014 Does the use of horn load necessarily solve anything apart from efficiency? Yes - directivity. You've forgotten to consider walls, floor, and ceiling reflections inside real rooms, or at least the ground in outside applications without backstops (i.e., band shells). Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 From this point is where the tradeoffs begin, right? I'm not sure I agree with the premise, nor the progression you're trying to make....it 'might' have some historical merit, but I'm not sure about that either. I think modern designers start with the wavefront desired at the listening position(s) - and then you work back to the transducer and let physics dictate the most straightforward approach. That wavefront is usually nothing like that generated from a point source so you don't even bother thinking/designing in that direction.... I know that's how I've approached the few designs I've done and am still working on. It's also how Keele described his approach and some of the guys at JBL that I met at a NAMM show a few years back... Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted July 23, 2014 Share Posted July 23, 2014 Hmmm? I can see how a perfect, infinitely small, point source radiates equally from any point on it's surface, but I can't see how that would happen by adding a horn to it? Of course we can't have point sources. So, someone thinks, why not sphere? Hard to make the sphere pulsate, so they cut the sphere in half and make a cone/dome speaker as the closest approximation of the point source. From this point is where the tradeoffs begin, right? You'd like to have the lowest possible mass to move, but you also need stiffness, and there you have one tradeoff. You like to have it be as small as possible, but you also need to produce low frequencies which require larger size or longer movement on one axis, and there is another tradeoff. You like it to be small and light, but you need to produce significant SPL, so you need a way to get more power out for some power in. I think this is where the horn load enters or exits the picture. Does the use of horn load necessarily solve anything apart from efficiency? There was a speaker years ago that was a sphere... Magnasphere as I recall. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted July 23, 2014 Share Posted July 23, 2014 I know that's how I've approached the few designs I've done and am still working on. It's also how Keele described his approach and some of the guys at JBL that I met at a NAMM show a few years back... I just had lunch with Don Keele yesterday. Even though he has designed THX and Academy Award winning horns for EV and JBL, he's all about CBT technology now and wide dispesion designs at all frequencies. He showed me a really cool prototype bookshelf speaker. I will be building two types of CBT's in the near future myself, just for fun, as soon as I have the money to play with. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 The CBT designs are very impressive indeed. I'd like to see a horn-loaded application. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 23, 2014 Share Posted July 23, 2014 Parts Express sells a cool Keele designed CBT kit -- definitely on my radar screen. How in the heck would you horn load THAT? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted July 23, 2014 Share Posted July 23, 2014 Parts Express sells a cool Keele designed CBT kit 2K just for the kit. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 Parts Express sells a cool Keele designed CBT kit -- definitely on my radar screen. How in the heck would you horn load THAT? The CBT kit from Parts Express is really cool in demonstrating the concept, but it doesn't go very loud at all and sounds like a classic direct radiator system: distortion and all. I would be interested in a CBT design that used horns for each of the drive elements rather than just direct radiators. Unfortunately the math needs to be modified since the polar pattern of the horn is different. Keele presented the CBT to an AES meeting in Chicago....he even referenced the K402 as one of the best examples of controlled polars. Afterwards I asked him how he thinks the CBT stacks up against the K402 and he basically said it wasn't fair because the K402 is hornloaded - and then he said the CBT would work quite well with an array of horns if you really wanted lower distortion. I immediately thought about an wall of K402's, but then after running some numbers I think the vertical acoustic centers need to be closer - almost necessitating a very narrow vertical expansion, but then you get the resultant distortion and reflections and whatnot - so it may not actually be a free lunch. I think the more straightforward approach would be just to provide a horizontal lense to a vertical array of drivers...maybe some coax drivers so it can dig all the way down to ~300Hz or so? Maybe do a cross between the CBT and the Synergy concept where the LF section fires into the side of the horn? Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 23, 2014 Share Posted July 23, 2014 Isn't the CBT a PA device? It's a mathematical approach to arraying speakers....doesn't necessarily need to be PA, but the couple of designs he did for JBL are intended for PA type applications. Quote Link to comment Share on other sites More sharing options...
Ski Bum Posted July 23, 2014 Share Posted July 23, 2014 Does the use of horn load necessarily solve anything apart from efficiency? Yes - directivity. You've forgotten to consider walls, floor, and ceiling reflections inside real rooms, or at least the ground in outside applications without backstops (i.e., band shells). As I survey the history, PWK emphasized low distortion, high sensitivity, and wide dynamic range. The later horn folks (Geddes, Parnam, the whole SEOS crew, Danley...even some Klipsch convergence from Roy with the 402) shifted the focus more toward controlled/constant directivity. If you liked the sonic qualities of those old Tektons, Mark, you would freak out on Danley Synergy horns. 1 Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted July 24, 2014 Share Posted July 24, 2014 So, someone thinks, why not sphere? Hard to make the sphere pulsate, so they cut the sphere in half and make a cone/dome speaker as the closest approximation of the point source. From this point is where the tradeoffs begin, right? You'd like to have the lowest possible mass to move, but you also need stiffness, and there you have one tradeoff. Read the CBT papers, the original Navy reseach on this. It's been done. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted July 24, 2014 Share Posted July 24, 2014 (edited) The CBT designs are very impressive indeed. I'd like to see a horn-loaded application. Keele told me you can make a CBT out of horns. My comment was, it would be REALLY expensive. He agreed. One of the KEY components is the LEGENDRE shading. Edited July 24, 2014 by ClaudeJ1 Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted July 24, 2014 Share Posted July 24, 2014 Parts Express sells a cool Keele designed CBT kit 2K just for the kit. I think it's 8K fully assembled. It's labor intensive but worth it. My next project will be the XL (2-way also) version and the 1 Way version for surrounds. Got lots of inside info. from DB Keele yesterday in 2 hours. Quote Link to comment Share on other sites More sharing options...
Max2 Posted July 24, 2014 Share Posted July 24, 2014 A few pics I found Quote Link to comment Share on other sites More sharing options...
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