Hello Camplo
They claim full horn loading to 200Hz and there is directivity control you can see it in the beam width plots. If you look closer they start really "working" at 500Hz and above. Closer to 1K on the 2366. This is where the claimed vs actual pattern control lines up. This make sense as in actual use 500Hz would be where the crossover would be. These are real measurements not simulations.
I don't understand you last line hear: Seems like every above 370Hz or so would be 180 degrees???
Also what with the posted plots for the 140hz vs 280hz are those simulations of your horn?? What are you using to determine pattern control?? -6db point so the contour from say 115 and 109?? on the 140Hz. Can't you plot them without the dead space out to 10 hz and change to say 200Hz and up???
Rob
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It is not about wanting to "hear" it a certain way, it just is that way. You need to learn the language that already exists to describe the fairy dust floating around in your head. Until you realize this every topic becomes an argument over the fact that you can't explain yourself.
Increasing the length narrowed the wall angle (as much as there can be one in a profile like this) which is why the high frequency directivity is now narrower.
Some of what you say ends up at the right answer but for the wrong reason.
Seems like every above 370Hz or so would be 180 degrees??? = Seems like everything below 370hz or so would be 180 degrees, wide open, completely loss of directivity....Hello Camplo
They claim full horn loading to 200Hz and there is directivity control you can see it in the beam width plots. If you look closer they start really "working" at 500Hz and above. Closer to 1K on the 2366. This is where the claimed vs actual pattern control lines up. This make sense as in actual use 500Hz would be where the crossover would be. These are real measurements not simulations.
I don't understand you last line hear: Seems like every above 370Hz or so would be 180 degrees???
Also what with the posted plots for the 140hz vs 280hz are those simulations of your horn?? What are you using to determine pattern control?? -6db point so the contour from say 115 and 109?? on the 140Hz. Can't you plot them without the dead space out to 10 hz and change to say 200Hz and up???
Rob
I tried to find polar maps and FR/impedance measurements, no luck yet. The 2365 and 2360 likely do not load to 200hz, it claims 350hz loading at the top of the article but it gives 350hz minimum XO for those horns ( then it says 300hz minimum use) ...The 2366 listed 200hz lower use limit, 300 lowest XO (lowest xo used with jbl 2485 rated to 300hz).... The 2366 is also 54" long. The other 2 are 32" long....My tractrix is 36" long and loads to ~150hz
Proper Xo would require at least a cutoff 1.5-2x under desired Xo, isn't that the general consensus?
140hz vs 280hz are those simulations of your horn?? - Horn Resp sims
What are you using to determine pattern control?? - Horn Respsims
Can't you plot them without the dead space out to 10 hz and change to say 200Hz and up??? - 10hz and up or 1hz and up...I put in a request to add option to change spl scale to -25db =)
Thats very authoritarian of you...I just need to get my info and context right is all. Definitely regarding the diff between horn dispersion and dynamic radiator.
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It was an excellent post; with real authority. Fluid got it right:
"You need to learn the language that already exists to describe the fairy dust floating around in your head. Until you realize this every topic becomes an argument over the fact that you can't explain yourself."
https://www.diyaudio.com/community/...ion-with-a-2-way.334757/page-466#post-6900553
You are arguing way above your pay-grade.
When will you actually add to the conversation? you are just a heckler
Fluid may be correct but he actually adds to the conversation, which is way more respectable then whatever it is you call what you do
So far, you bought the book I recommended. Perhaps you will learn something from it. Perhaps not.
You've been given good info and advice here from a lot of people. There isn't one of us you haven't stomped on.
Pearls are being wasted.
The good thing is the info and advice can be used by others who read here, and who know the technical world is not defined by camplo-isms.
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I think what many folks have been trying to tell you, is that most of the "pearls" appear to be the product of self-stimulation.
What this makes me think of is the polar pattern of the next driver in line....the driver below the horn has similar directivity at 555hz and 370hz....if I cross at 555hz the pattern goes from 60degrees to 90degrees...if I cross at 370hz I go from 90degrees to 90degrees, and the pattern is still 60degrees at 555hz....So if I take the horn down till it looses directivity, I will have the most directivity I can get....which makes sense if the horns mouth is the same width as the baffle....at ~30" width, baffle vs horn mouth, the axial length and wall angle creates more directivity
Camplo, the crossover slope will be a function/summation of both the horns cut off and the electrical cutoff of the filter. You need to take this into account plus the physical Z offset between the acoustical centers to get your filter to work. I suggest you take a look at some of the TAD/Kinoshita designs out there with a side to side configuration to gauge their complexity.
OK, I tread lightly around this Z topic because I was certain that it was a very simple problem and solution yet I am still learning so, here goes;
Z offset....Time alignment of each driver...Z offset is 0... I thought this was status quo....
Regarding cutoff and Xo....Yes....the purpose of the 150hz cutoff is to be able to cross over close to 300hz with no issue.
Is there more?
Personally I see no "complexity"....its woofers side by side. The issue that side by side woofers have can be mitigated by lowering the XO....Viewing window and listening proximity are an issue...I don't exactly know the math on the issues or the range of issues but as for comb filtering as an effect on FR I can simulate this and see it in VituixCad. The most experienced person I talked to on the subject, described a "phasiness" experience with side to side head movements, regarding the above design (2401 twin)....I'm not sure how to view this in the Simulation if even possible...it might be as simple as looking at the phase? Can we hear phase changes?
Z offset....Time alignment of each driver...Z offset is 0... I thought this was status quo....
Regarding cutoff and Xo....Yes....the purpose of the 150hz cutoff is to be able to cross over close to 300hz with no issue.
Is there more?
Personally I see no "complexity"....its woofers side by side. The issue that side by side woofers have can be mitigated by lowering the XO....Viewing window and listening proximity are an issue...I don't exactly know the math on the issues or the range of issues but as for comb filtering as an effect on FR I can simulate this and see it in VituixCad. The most experienced person I talked to on the subject, described a "phasiness" experience with side to side head movements, regarding the above design (2401 twin)....I'm not sure how to view this in the Simulation if even possible...it might be as simple as looking at the phase? Can we hear phase changes?
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Simply stated a horn such as yours is probably imposes a 4th order crossover in itself at cutoff. With the intrinsic cutoff of the horn at 150Hz and the electrical cutoff 1 octave above that it's not going to be a true 2nd or 3rd order, or whatever, filter.
Edit: How are you achieving Z=0 physically with such a huge horn?
Edit: How are you achieving Z=0 physically with such a huge horn?
Does the slope of filter matter? a 48db filter at 300hz isnt going to be true? I can only speculate because I have not the actually response to play with....I do have this FR to play with...my best guess AxiSim with a round tractrix sim about the same width as my e-tractrix horn lol....the ballpark way
I was thinking that it might be wise to cross at where the horn looses directivity, this approximate 330-370hz.
Is this idea of being "true" to the slope, relevant?...isn't the end goal of a flat resulting crossband...the decider? Meaning that if I can achieve that, I can move on? Or is there more to this idea of being true to the slope...
I was thinking that it might be wise to cross at where the horn looses directivity, this approximate 330-370hz.
Is this idea of being "true" to the slope, relevant?...isn't the end goal of a flat resulting crossband...the decider? Meaning that if I can achieve that, I can move on? Or is there more to this idea of being true to the slope...
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Leaving aside the issues of the Yosemite Halfdome filter, your acoustical filter will be a composite of the two, horn cutoff and electrical. I suppose at some point the added effect will be moot but you still have to make the woofer hand over nicely. I would look at it the other way, you have free slope from the natural cutoff, work with that and don't try to beat it.
Is that a thing!? I was getting wind of this from some of my readings but my first thought was that something would be wrong with excursion...time to look at horn resp.....wait a second....are you suggesting to layer an electrical filter on top of the mechanical one.....or to not use an electronic filter, period lol....
Forget the horn for a moment. Just measuring the twin woofers will reveal any directivity mismatches that might occur when handing off to the horn (after it has been measured). There most likely will be off axis horz. nulls with the twin woofers. Where and how wide these nulls are can only be determined by measurement.