thanks for articulating this so well Pano. The way I look at it, it if I can see the driver mouth/throat then it's a shallow horn. 😉
Yep. I’m right there with you. 👍
Now one notable exception to shallow horns for me is the Tom Danley SH50 It’s not very deep and a conical horn, but sounds deeper to me.
Hi Pano, my take too .... tighter horn patterns, like the SH50's 50x50, sound deeper than wide angle horns/waveguides.
One of the few things i feel fairly certain about with about conical horns, is the narrower the pattern control, the deeper they physically have to be.
I know on on conicals, where the CD is not eclipsed by any throat geometry, that the horn pattern necessitates a particular horn depth, given a certain low frequency pattern goal.
And that necessary physical depth creates a sense of acoustic depth...
leading to the narrower the pattern, the greater the sense of depth.
It helps me picture basics when the throat isn't much in the picture....
And for me, makes me think it's not about if i can see the driver in the mouth/throat.
Yeah the video confirms that they might work well for me on the 803 horns that are currently high passed at 500 4th order. They might survive that crossover point.
Interesting...
I think there is a common thread here (and clearly misattribution as to the root characteristic apparently being attributed). I'll post a raw response of a couple of drivers on a K-402 horn for future reference:
and a polar sonogram of a K-402/K-69:
Chris
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Cask05,
what misattribution are you talking about? I am having a hard time following and correlating your point with my subjective impressions.
Can you clarify and be as wordy as you want to be in doing it? I really want to try to understand. 🙂
what misattribution are you talking about? I am having a hard time following and correlating your point with my subjective impressions.
Can you clarify and be as wordy as you want to be in doing it? I really want to try to understand. 🙂
Chris, you have misunderstood or read into my statement about the SH50 as negating what I had said before, but it doesn't - that's why I use the word "exception." The SH50 is a long way from the typical 1" CD on a shallow waveguide.
Please state your case and present your evidence as to why you believe horn depth has no audible effect.
Please state your case and present your evidence as to why you believe horn depth has no audible effect.
.........😗.........
...No, I've been taught quite well to be concise, not complete. I'll try to keep this short, but complete enough to follow the train of thought. I'll present the more socially acceptable part, first...
First note that I never said that horn depth had no effect on your subjective perception of "What A 'Good Horn' Should Sound Like" (let's use "WAGHSSL" for short, since I think this is going to come up again). I implied that your perception of a "shallow horn" where you can see the horn throat open area at the mouth of the horn at the designed off-axis angle (e.g., notionally 45 degrees for a 90 degree coverage, etc.) is not really the source of the horn/driver sound quality differences you apparently cherish.
You might note that I posted a couple of plots above in #708, but curiously, you didn't ask about those two plots. I posted them to let you (or your subconscious perhaps) ponder where I was going--since my intent is not to surprise but rather to illuminate the phenomenon a bit more.
If you consider a direct radiator, such as a cone or dome driver on a flat baffle as a limiting case, you might also associate the term "baffle step". This is nothing but the loss of polar control of the first 1/4 wave of sound at the point where the "180 degree waveguide" (the baffle, that is). So the closer the horn coverage angle is to 180 degrees, the lower the "horn gain" of that driver or those drivers, and more that the phenomenon known as modulation distortion becomes the real difference in the sound quality of "horns vs. direct radiators". Still with me here? (I'm assuming you're an old horn guy at this point and can follow this line of discourse.)
So as the horn coverage angle gets wider and wider, the more the driver's diaphragm has to move (all other things being equal) to maintain a certain SPL on axis, and almost as much diaphragm motion is required to maintain a certain SPL in-room (factoring in the early reflections around the loudspeaker being perceived in the Haas interval as direct arrivals). Still with me?
So I think is occurring in your WAGHSSL definition is that you're very sensitive to at least treble modulation distortion, and probably compression distortion if you evaluate your loudspeakers listening at 100+ dB SPL (1m) for any length of time--using very dynamic recordings. The Altec A7- which in the past was your go-to system of record, Pano, crosses notionally at 1250 Hz. That means that the bass bin's very short horn must control anything from that point downward (and I don't have directivity plots for the A7 bass bin, unfortunately). So modulation and compression distortion enjoy a breakpoint/separation at that 1250 Hz (notionally) crossover point. So that means you're not so sensitive to bass bin-generated midrange modulation distortion, since I've not seen you talk about full-range horn-loaded bass bins like a La Scala, FH-1, Belle, Khorn, or Jubilee enjoy. So somewhere in the lower midrange, you're listening to higher levels of midrange modulation distortion if listening at or above say 83-90 dB (which I find a lot of horn enthusiasts will listen in the music transients during dynamic recordings).
Still with me? Okay, so Pano, you listed a bunch of horns (i.e., the ones you could remember their names). The largest one was 10". Those plots in that link show the horn dies at ~1 kHz (probably due to the one inch compression drivers used, which is usually about as far as 1" compression drivers go unless using a Klipsch K-55 (a hand-selected Atlas PD-5VH with slightly closer phase plug spacing--which goes down to 200-400 Hz, but dies at 5 kHz). I think you're really talking about directivity control down to a lower point than 1 kHz, combined with some other subjective listening traits that I'll keep to myself for the present, as well as lower modulation distortion that you get with direct radiators.
So how do we avoid loss of directivity control down to (at least ) 500 Hz? A larger horn mouth (hor, vert). How do we avoid treble modulation distortion? Good horn loading, or a larger diaphragm area (i.e., 2" compression driver rather than 1") if crossing as low as 1 kHz.
So why do you think the SH-50 sounds like a "deeper horn" by the above argument? Well, modulation distortion is controlled due to a good handoff from the 1" compression driver (which I think dies at ~1 kHz and is crossed at ~1750 Hz to the multiple cone midranges). You can still see the throat entance from the horn mouth at 25 degrees off-axis, but you aren't detecting what you might call "short horn syndrome". Directivity control is very good down to ~500 Hz, at which point the horn begins to gradually lose directivity control down to about 175 Hz:
Do I need to say any more to highlight what I've said? There is a lot more I could talk about, but I've been taught to keep it as short as possible, so I stop there for the moment.
Chris
Thanks for the explanation Chris, but it mostly doesn't work for me.
The stock A7 crosses at 500Hz when using the 511 horn and 800Hz when fitted with the 811 horn. Neither of those crossover points work very well with those horns and 1" drivers, but that's what Altec supplied.
No. My go-to system is the A5, which uses a larger horn and driver than the A7. I've run the A5 with 300Hz and 500Hz horns. I tended to high pass the horns circa 600-700 Hz. 500Hz with a coaxial driver, but that's pushing it.
The stock A7 crosses at 500Hz when using the 511 horn and 800Hz when fitted with the 811 horn. Neither of those crossover points work very well with those horns and 1" drivers, but that's what Altec supplied.
Not exactly. The short front horn on the 828 bass cabinet has directivity control down to about 300 Hz and side wings were added to extend that a bit. But that short horn is loading a 15" woofer, not a 1" or 1.4" exit compression driver. Very different things. I don't have the directivity plot of the 828 bass horn, but it shouldn't be difficult to figure out. The size of the bass horn and the size of the big multi-cell horns seems to match well, they blend together nicely. It's difficult, even up very close, to tell where one ends and the other begins. (but that's another topic)
No, the largest IIRC was 12", on the Gedlee speakers. Or 16" if you count the P.Audio 18" coax.
Yes, that is about right for small, shallow waveguides.
Yes and yes. Acoustic impedance is very different for long and short horns with the same entrance and exit diameters. Does that correlate to "loading"? Probably a good bit. A long horn, or at least a narrow throat, means higher acoustic impedance at a lower frequency. For example a shallow expo horn has an acoustic impedance plot that reaches down lower than the same size conical horn. The initial expansion rate matters.
That has to be a large part of it. The SH50 isn't asking too much of the CD, as it gets handed off earlier. Also, if you've seen an SH50 or SH60, you might notice that you can't see the compression driver throat. Voila! Mystery solved. 😉 Just kidding of course, but the SH50 isn't as shallow as some popular waveguide types. Those Dayton waveguides are about 55% as deep as they are wide with a very rapid expansion, the SH50 is (a guess) about 85% as deep as it is wide. I don't know the diameter to depth ratio of the Gedlees waveguides, but they are not a deep horn.
This isn't a phrase that I have used, so it isn't accurate to ascribe it to me. Those are not the terms I used nor was it my meaning.
Sorry but the SH-50 in my storage room is straight-walled, then has a short secondary taper near the mouth. You can see the compression driver throat easily out to its design coverage angle (50 degrees included angle). I can include a picture if needed. The other wider coverage Danley Synergy horns are all shorter.
I'm actually not sure why this is important that you can't see the driver entrance from the horn mouth off-axis coverage angle--and that it is a "good thing". I didn't include that portion of the explanation above for a reason...but I can launch into it if you wish to. It likely won't be a feel-good exercise. Your choice. It starts out by saying that beaming highs are never a desirable thing. It goes downhill at that point.
I read the 1250 Hz crossover point with a setup using a 311-90 horn (also mentioned above). My bad. I did think at the time that it was too high for the bass bin woofer to cross, so it's nice to know that it crosses lower. The crossover interference band seems extremely narrow for those designs--sort of like the tweeter/midrange interference band in PWK-designed Klipsch Heritage models (i.e., 4.9 kHz ±200 Hz center frequency).
Chris
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Sorry Chris, you missed the joke.
Not seeing the bug screen is just a rule of thumb. With shallow horns it easy to see.
There is no argument that will make me prefer shallow horns to deep ones. Similar to the way I can enjoy and appreciate a good fullrange speaker, but it doesn’t give me the satisfaction of a big horn system. I simply don’t like the sound of shallow as much as I like the deep horns. After decades of working with horns I have learned what I like and don’t like.
Not seeing the bug screen is just a rule of thumb. With shallow horns it easy to see.
There is no argument that will make me prefer shallow horns to deep ones. Similar to the way I can enjoy and appreciate a good fullrange speaker, but it doesn’t give me the satisfaction of a big horn system. I simply don’t like the sound of shallow as much as I like the deep horns. After decades of working with horns I have learned what I like and don’t like.
for me it's the opposite , i don't like long tratrix horn and prefer short profile like JMLC or ARAI more appropriate for home use distance . but the real deal is to have the horn made specially for the compression driver like the Tad Horn , Onken , Altec with the their throat angle matches the entry of their horns.
Sorry but I set my threshold for humor artificially high when posting on forums. I've found that almost all forum melt-downs occur when humor is misunderstood or injected into these type of discussions. It's much safer to ignore any attempts at humor but the most obvious ones.
Thanks for simplifying the argument. You're willing to trade what you want (in this case, older 1950s-70s horn profiles) and accept high frequency polars with beaming.
Personally, I've heard the difference (for many years now) and I can tell you that nostalgia isn't something that replaces acoustic performance. If you are willing to settle for beaming HF polars, that's your prerogative, but it's been my experience most people will choose the better polars given honest comparisons. Honestly, we probably also wouldn't be having this conversation at this level of detail if your posts didn't say "Administrator" but instead, "Member", so that regular blokes reading this don't misunderstand personal opinion for forum endorsement. I've found it better to know if the forum is still honest and open before investing more time and effort. [I spent 15 years on another forum that suddenly changed its policies to "we don't like your (open and honest) opinions now" and started deleting user posts and threatening users. That forum has basically collapsed in terms of current participation since that occurred.]
I do think Toole and Olive (...and others...) have showed fairly conclusively that people will select what sounds better given the chance to honestly choose without sighted bias (and having reasonable hearing facilities). Nostalgia, branding, etc. don't matter.
Chris
No Chris, that is not correct. That is why I use multi-cell horns. But there are other deep horns that don't beam.
When I can replace highly engineered, modern line arrays with a single 18" woofer topped by an old Altec multi-cell horn and get far more even coverage, intelligibility and SQ across the audience, then I need go no further, I've found what works. I don't even need to consider how well that works at home, the proof is right there in the air. No amount of hand waving by modern audio salesmen can ever change that. At some point in my experience I have to say to myself "this works better than that" and not let people with a sales agenda change my mind. There is little to no sales profit for the audio industry if I use 60 year old horns, so to audio pitchmen they are bad. (a least publicly) And no one is going to mass produce the old designs, they are too clumsy and expensive and we've been told they are not good. Not enough money to be made.
I use what works well for me out of almost a century of audio design. If that's some new coaxial or carbon fiber compression driver, cool - I'll use it if it works better than other drivers. If it's a horn designed in the 1930s or 40s, cool - I'll use it because it works better than other designs. Modern design is interesting to look at, understand and follow, but I take the sales hype with a large grain of salt. People love to have new designs and ideas to hype and sell, it's a way to make a living. And to make the new designs look even better they want to tell us how bad the old stuff is. At this point in my audio life I know from experience what works and I stick to it.