Ooops, sorry gawdbless! My mistake. Must be getting old.
I miss my memories... I think.
Duke
Showing 10 responses by audiokinesis
Love the topic! Thank you Eric!! Most horns are designed with acoustic amplification as the top priority. A few are designed with low coloration as the top priority, Some of those have the potential of imaging well. I’ve been working with horns and waveguides for many years now, and during this time I’ve had the privilege of working with Earl Geddes, whose waveguide-based designs (a waveguide being a particular type of horn in this context) image extremely well and totally disappear as the apparent sound source. Okay time to get nerdy: The ear/brain system gets its localization cues from the first approximately .68 milliseconds of sound. In that time, sound travels about 9 inches (corresponding to the distance around the head from one ear to the other). A poorly designed horn has lots of opportunities to screw things up within this time window. Reflections and diffractions within the horn will happen during that first .68 milliseconds. Diffraction (from sharp edges and discontinuities) is worse than reflections. Reflections within the horn are inevitable, but some geometries generate more internal reflections than others, and/or direct more of these internal reflections towards the listener than others. My understanding is that the best horn geometry from the standpoint of internal reflections is the Oblate Spheroid (what Earl uses). I use a Super-Elliptical Oblate Spheroid which comes very close, and which may have a couple of advantages in other areas. So to sum it up, proper horn geometry is absolutely crucial if imaging matters. Most horns screw up that first .68 milliseconds of sound, but a few are benign in this respect. Those are the ones that have the potential to image well. Here is a link to a show report that comments on the imaging of one of my systems. My room is covered starting about 1/4 of the way down from the top of this page, and the writers are Tyson and Pez (Jason) from AudioCircle.com, who for several years (before they burned out) were arguably doing the most precise show reports of anybody because they pre-selected their rooms, listened to the same few short revealing tracks in each room, wrote quickly, and then moved quickly to the next room on their list: https://www.audiocircle.com/index.php?topic=120504.msg1267150#msg1267150 In his subsequent "Best Of" report, Pez had us tied with several rooms for second place. For some reason I can’t post the link. Anyway, he wrote: "This room had the most locked in soundstage and imaging I have ever heard bar none with dynamics to match. The sweetspot is just an incredible experience and really musical top to bottom." Did you catch that? A HORN system had "the most locked in soundstage and imaging I have ever heard bar none". Tyson had us tied with one other room for first place and wrote: "Basically did everything as well or better than any other speaker at the entire show... And, amazingly, they did it with zero room treatments." (We have good radiation pattern control and we aim those patterns intelligently, so we can get away without room treatments if we want to.) If anybody is going to be at RMAF 2018 next weekend, you are invited to Room 3002 to find out firsthand whether or not "horns done right" can image well, and/or otherwise compete on the basis of freedom from coloration, natural timbre, disappearing as the apparent sound source, precision, and whatever else horns traditionally are presumed to not do well. Duke got dogs in this fight! |
@d2girls asked: "what horns will be in room 3002?" One of mine, a new model making its debut. It’s called the Azel Stand Mount, and it’s not up on my website yet. 12" midwoofer, 1" throat Beryllium-diaphragm compression driver on a 15" SEOS waveguide-style horn. Rear-firing tweeter compensates for a radiation pattern mis-match between midwoofer and horn by fixing the spectral balance of the reverberant field. Crossover is kinda neat in a kinda nerdy way... starts out first-order and then accelerates to fourth-order. Two pluggable ports to work with different boundary reinforcement situations, and user-adjustable treble-tilt via a high-quality external resistor. @gawdbless asked: "hey Duke can you please confirm what speaker/s you will have in the 3002?" The entire system also includes the new "SuperStands" (so named because there just isn’t enough hyperbole in high-end audio these days). The SuperStands incorporate a built-in subwoofer and an adjustable coaxial driver dedicated to the reverberant field, the latter being an application of the "Late Ceiling Splash" and/or "Space Generator" concepts I’ve shown with a few times. The SuperStands will theoretically work with most stand-mount speakers. Finally we’ll have two (optional) outboard subs positioned somewhere in the room, so that we’ll have four distributed subwoofer modules in total. Placement flexibility is not quite as good as with the Swarm because two of the subs are stuck doing double-duty as speaker stands, but we still expect to get pretty good modal smoothing. "I hope to pop in, nay WILL pop in......." SWEET!! Looking forward to it. Didn’t you show a killer system with Mangers in a rounded upper cabinet once upon a time? Duke |
@gawdbless and @d2girls, you might also want to check out Room 542, where Peter Noerbaek (of PBN) will be showing his M2!5’s... same horn and compression driver as the JBL M2, but TWO of the M2’s woofers, if I understand correctly. My guess is that speaker will do a LOT of things very well. Assuming I get a chance to sneak away at some point, probably Sunday morning, THAT’s the room I’m heading for. Also I plan to hit the Classic Audio Reproductions room, a perennial favorite of mine, another big and actually beautiful horn speaker with amazing field-coil drivers. D2girls, you’ve got JBL 4367’s, right? So you are done with speaker shopping. But if you don’t mind, I’d love to get your brutally honest opinion of how my system compares. And in my comments above where I was talking about reflections in horns, I forgot about this latest generation of JBL horns. I think their unusual internal geometry is specifically aimed at making sure internal reflections are directed away from the listener, and I bet they do an excellent job of it. Duke |
@phusis wrote: " but in any event I find singling out particular horn geometries as "the best" to be more of a marketing ploy to boost business than a marker of the diversity of great sounding horns out there." My statement about the Oblate Spheroid profile was based on my understanding that it is the mathematical optimum for minimizing detrimental internal reflections within the horn. There are other profiles optimized for other things - minimum phase, wavefront preservation, etc. Duke |
I was in the room next to Volti for several years at RMAF, where Greg was showing the Vittoras. Magnificent speakers. Being a competitor I really wanted to hear "something wrong": with them, and utterly failed. Kudos to Greg Roberts for his speaker designs, and for making his expertise available to people with Klipschorns and Klipsch Belles. Duke |
@phusis wrote (in a reply to me): "my main gripe comes with questioning the usefulness, in some instances at least, of knowing about minutiae design "tech details" and how these are convertible into or relate to actual perceived sound. The designer/developer him- or herself should have a closer bearing perhaps, but oftentimes I feel such knowledge presented to the end user, illuminating it may be as a field and entity in itself, has a tendency to produce disciples almost or followers of a brand/principle rather than critical, informed individuals that would seek not to equate too easily." Erik’s thread is entitled, "Why don’t horns image well?", and the entire text of his opening post is, "Anyone have a theory?". In asking for theories, it seemed like Erik was inviting "tech details" as well as how they "relate to actual perceived sound". My mistake. I don’t wish to impose anything unwelcome on you or on anyone else. Duke |
The best imaging I have ever heard from a well-off-centerline listening location was with the fully horn loaded ESD speakers at RMAF last weekend. Very narrow-pattern horns (even the bass was horn loaded). The center image was extremely solid and precise. If blindfolded I would have sworn there was a center channel speaker of the same caliber as the left and right speakers. I didn't know ANYTHING could image like that. Duke |
Peter Noerbaek (PBN)'s new flagship is a horn... and ime it’s an absolutely magnificent speaker. It uses the horn and compression driver from JBL’s M2 studio monitor, with TWO of the same woofers that the JBL uses. To the best of my knowledge this is Peter’s first home audio horn speaker, and he has a LOT of experience building excellent large, high-output loudspeakers. Unfortunately most audiophiles listen with their eyes, and so Peter’s magnificent M2!5’s are still under-the-radar. In the high-end studio main monitor world, performance is what counts the most. Recording engineers don’t listen with their eyes, and in that world horns are much more widely accepted. Augspurger, Westlake, TAD, JBL and Kinoshita come to mind off the top of my head, and many if not most companies that use direct radiators in their high-end mains use waveguides (a type of horn) for their midrange and tweeter drivers. By the way, coaxials like the Tannoys and KEFs and Spatial Audios are horns. The midwoofer’s cone is the horn for the coaxial tweeter. Last I heard, people had nice things to say about the imaging from these designs. Not all horns are created equal, just as not all cone-n-dome speakers are created equal. But ime "horns done right" have greater potential than the cone-n-dome format, which is why you see horns showing up in flagship speakers from companies whose other designs are mostly if not entirely direct radiators. Duke |