Just a note here, as I think it's appropriate. The "X-Shape" uses a "trick" with the constrained throat horizontally, making it effectively smaller in that direction. With data presented from that exact horizontal plane, it looks very good, but this behaviour gets lost pretty quickly as you move from this exact plane. I made these experiments in the past ("BLD") and must admit it's a nice trick. Still only a trick though. In fact the performace of the device everywhere else will be much closer to its vertical performance, or worse.
Last edited:
You right but not mine, I call it the cross syndrome, some other horn are concerned (that don't look the same at all), the "trick" is average of profile principle.
it possible that some modern JBL has it but it need to be measured.
It's why I fix it thanks to FEA 😉
https://audiohorn.net/sciences/cross-wavefront-syndrome/
Polar on diagonal, accident after 14khz is due to out of plane wave radiation of the compression driver, as usual.
It's really good for a diagonal that is usually the worst place to take a polar.
it possible that some modern JBL has it but it need to be measured.
It's why I fix it thanks to FEA 😉
https://audiohorn.net/sciences/cross-wavefront-syndrome/
Polar on diagonal, accident after 14khz is due to out of plane wave radiation of the compression driver, as usual.
It's really good for a diagonal that is usually the worst place to take a polar.
So what's the true DI for this device? Do you have it? It should be no problem for FEA either. Now this looks pretty ordinary to me.
All your data look terribly smoothed, BTW.
All your data look terribly smoothed, BTW.
This is best proved by showing the throat impednace. Or is it a problem for FEA?
When I look at your waveguides and the same drivers as I've tested, I see they reach about the same low frequencies as my waveguides. And I would certainly not call them "huge loading" (a "bit better than usual", perhaps) . Again, this may be a problem of a definition. So, what exactly do you call "huge loading"? 🙂
I prefer the GD in situation because it takes everything into account (of course, directivity and distortion must also be taken into account), after the EQ. Loading is not something uniform. But I notice you added a kind of throat tube like on your horns, after criticizing the design of mine and attempting to steal authorship some time ago 😉. So on yours, yes, yours too, congratulations!
Loading can be directly simulated, it's not uniform, I will not help you (again 🙂 ).
Loading can be directly simulated, it's not uniform, I will not help you (again 🙂 ).
In the spirit of the origin of this thread, we’re not breaking any new ground here folks……new clothes for old ladies is all I can take away from the past 4-5 years this thing has lingered on. Sounds great to some……but just smells like mothballs and cedar to me. These huge systems kinda remind me of vintage seaman’s trunks…..too much nostalgia being repurposed here for sale in the new age audio thrift store. And mostly from old dudes whose outer ear waveguide is collapsing under its own weight, desperately trying to recapture their aural acuity.
Fellas…..get a really comfy chair, a great pair of Audeze headphones and embrace your seniority. Close your eyes, Add in a little aroma therapy and I guarantee that all the sights and sounds of a Friday night at The Blue Note will come rushing in like waves.
Fellas…..get a really comfy chair, a great pair of Audeze headphones and embrace your seniority. Close your eyes, Add in a little aroma therapy and I guarantee that all the sights and sounds of a Friday night at The Blue Note will come rushing in like waves.
Don't be ashamed to show it, we are used to see throat impedances. It's "huge", so it must be something worth showing.
NicoB said:
Or is it actually not so huge, after all (as usual with your claims)?
"A system which has a rising on-axis DI cannot be successfully equalized, because the on-axis response will tend to rise at high frequencies."
Might this mean for example that you can equalize the Radian745Be/TH4001 combo for relatively flat off-axis response but not the same driver in the AH425 horn?
Okay, then I presumably this is good. https://www.parts-express.com/Speaker-Grill-Cloth-Black-Yard-70-Wide-260-335?quantity=1
I was only asking those questions to try to confirm if that what Camplo at least seemed to me to be implying. But at least most of what you've said seems to confirm my correct interpretation of same. FWIW, as I've yet had the opportunity to hear JMLC horns (have you?), I can't know how much of a head is vise experience it would be for me. Certainly, Lynn Olson wouldn't classify the 425 as such; post 15235.
In any case, as one major goal has been pursuit of direct "I am there" sound without consequence, I've been all along here seeking measurements and recommendations (OOPs! Is the latter a dirty word here??) for horns which if not true CD horns are very close approximations above ~ 700Hz. But I can't recall a single horn discussed here, at least during the last two months, whose plots show it to be a CD horn. The last suggestion was http://www.alg-audiodesign.com/pavillons-mono-cellule/
However, at least to my understanding, the DI curves of the JBL 2360A in that tech bulletin you just posted look extremely good; see attached.
But MUST it be so gigantic?? Isn't there a smaller version for home use? OR another CD horn with equal or better performance?
Should be OK, but probably not stretchy enough to conform to a horn roll-back contour.
To have pattern control to lower frequencies the mouth dimensions need to be similar to the wavelength.
The JBL 2380 has similar horizontal directivity as the 2360 in a much smaller package, though the reduced dimensions raise the pattern control frequencies accordingly.
The reduced vertical dimension allows a closer center to center distance to the woofer, an advantage for closer listening distance.
Both the 236x and 238x series throats are pinched to ~1", the diffraction this causes is used to achieve the even polar response.
Diffraction does not sound as "pure" as your AH425 horn's response, one of those trade offs required for wide constant directivity past 10kHz using 2" exit drivers.
Try to understand that off-axis response (other than at VHF) is a property of the horn, not the driver.
Frequency response can be equalized to any response desired, within limitations of the driver.
A horn like the AH425 with rising on-axis DI can be equalized, but it's response will only be the same on that particular axis, "failure" rather than "success" in PA use where it is important for each portion of the audience to receive the same response whether they like it or not 😉
In your home listening environment you only have to please yourself.
With a beaming horn, if you prefer the sound to be more "dark", sit more off-axis, more "bright", more on-axis, no EQ required for multiple response variety.
Art
I think that the original Iwata profile would fit to your needs / expectations:
https://www.audioheritage.org/vbulletin/showthread.php?31481-Are-Iwata-horns-that-good
It is looking very nice and seems to have good acoustic loading. Personally, I don't like the jmlc Iwata variant.
Another option but maybe much more expensive are the Yamamoto horns without fins SS-500 or better SS-300.
The opening sentence... maybe its a language thing. "The opening coverage" needs a definition. It being "given where its constant"... as if to say, if DI is never constant there is no coverage. I think you are trying to neglect the spectrum in your horn above its constant DI area, an easy way to dismiss this area when peers question it? If it didn't matter then why would Mabat create a waveguide/phase plug that allowed Constant Directivity to reach 20khz? I say everything you can perceive matters and I can perceive signsal over 10khz.
I don't know if Geddes or Toole said what you claim. Id rather not guess. Maybe we can find what was actually said, so that we can maintain proper context. Making sure to reach constant DI through the critical zone, is pretty logical. Maintaining constant DI to 20khz is just as logical and a step above, the former.
The equal loudness contour is something that is already taken into consideration when the signal was designed, it is a major concern of the sound engineer designing the material. It is the job of the loudspeaker to be a transparent reproduction of the signal that has already been designed.
"They all have a sweet spot vertically"??? "If you want a horn that provide no sweet spot on both axis, "??? - I think you mean; they all tend to beam vertically or they all have a narrow sweet spot on the vertical plane. Every loudspeaker has a sweet spot.
"It's a matter of preferences but it's important to be constant horizontally in the plain audibility range as I or other specialist or acousticians said."
- There's a lot of things said. Constant directivity is not my enemy. Show me a Constant directivity Horn/Waveguide with a 40 degree wide pattern and I might be interested. I have no desire to hear sound reflected off of walls any more than necessary, the higher the DI the better for me. We are focused as if constant directivity is the main issue when really yours and other popular horns beamwidth is simply too high for a person who is interested more so in accuracy instead of being able to have an audience spread out horizontally.
A Smooth On axis response void of large peaks n nulls is more important than Constant Directivity.
A Smooth off axis transition void of large peaks n nulls is more important than Constant Directivity.
A Smooth transition of DI from one part of the spectrum to the other, particularly a Smooth rising DI, is only second to Constant Directivity. These 2 outcomes, Smoothly rising DI or Constant Di are completely acceptable for critical listening in my opinion.
Where the controversy truly lives is in achieved DI. Above, I think I've done a fair job in prioritizing the aspects of Dispersion. Toole has said the on Axis FR is the most important subjective aspect of sound quality, and that a smooth non coloring response is the most desirable. He says a smooth and relatively constant DI is choice. The rising DI of a well designed exponential horn is definitely smooth. We could debate on the aspect of how relatively constant the DI is, I guarantee if it was designed by Docali there would be no issues.
The DI achieved in a lot of the horns and waveguides I've analyzed is higher than what I desire. Over time I've realized that Dr. Geddes waveguide is of higher DI than I originally thought. It seems you and others seek to replicate the DI of the Geddes waveguide. Not a bad idea being that 60 degrees will be a happy median... I may represent a niche of listeners who desire "very" high DI as 60 degrees seems too wide in my opinion, I'd try 30degree n 40degree till -3db to begin with.
I am with you that those narrow horns have a special sound. I own a Selenium 40x20 horn, and it is fairly constant within this coverage angles. iirc they produced a very dynamic sound and a deep sound stage at the sweet spot (they are there). If you can live with this quite narrow listening window, then it is fine for you. It is easy to design a narrow and constant horn, but you will not find it anymore in the market because the demand has changed towards much wider coverage. There was also a trend to shorter devices. But I don't want to claim that you are completely old school ;-) 👍
Not when you move off axis.... when you move past the sweet spot. The sound power in the room never needed to be identical in the first place. It needs to be smooth, without large resonances or nulls. As I said before, the sound power, if a small room, comes more like that of a large room, hardly a problem.
DI. The older exponentials tend to reach a much higher DI in parts of the upper spectrum. If you have a large horn like mine, a good amount of the HF will have a smaller beam width than 60degrees. Beamwidth is a factor of a particular design, not constant or rising DI. My mistake for kinda talking as if this wasn't the case. I tried to clarify that on my last post.
A CD waveguide can be designed to have whatever DI the designer choses. Within the characteristics of such, an exponential is no different. That being said, I have not personally seen a constant activity wave guide design to have a smaller beam with than 60°. The traditional exponential horns that are available are reaching 15 to 10° by the time it reaches 20,000 kHz
Clarity increases with directivity. The higher the DI, the less indirect sound that is created. Indirect sound can be argued to be a form of distortion. This increasing clarity is not subjective and can be measured. If we have two constant directivity wave guides and one with significantly higher directivity than the other, the wave guide with the higher directivity will give a measurement that shows a significant clear impulse response. The increase in indirect sound only increases comb-filtering, group delay and decay.
Last edited:
Why can't I find any directivity plots for the AH425 in this GedLee https://cdn.shopify.com/s/files/1/0...BMS_4591-8_off-axis3_480x480.png?v=1649504045 or in that (?) format for the JBL horns from your last post?
Difficult to interpret. https://www.diyaudio.com/community/attachments/ah425_field_-gif.128080/
Why not just one plot from ~ 200Hz to 20kHz?
I too was surprised when discussing the availability of his speakers ("the tooling is all gone")-particularly the NS15 http://www.gedlee.com/Loudspeakers/NS15.aspx -Dr. Geddes replied
Regarding “perceptions”, you have things backwards from my thinking. A wide directivity will have many early reflections which tends to yield the “I am there” perception on live venue recordings. A very narrow directivity – like my speakers are designed for – will have very low early reflections and yields a very high “they are here” perception – especially on studio recordings. Live venue recordings have a mixed perception depending on the recording technique.
This is how I view the situation and what I have experienced.
That way of plotting would be better at conveying some of the information of interest to a horn designer. If those are Bjorn Kolbrek's plots that body of work was revealing and worth reading if you design horns.
I'm sorry to hear you are still undecided. Are you searching for a low diffraction horn with the directivity the room requires? Those should really constrain your decision.. for example when you go deeper into what's necessary the compromises should be jumping out at you. This should be causing you to cross things off your list.