I have other infos for reality. Plane wave radiation is theory, but in a real life setup there might be always a curved wavefront at exit. Even 18s confirms that it is not exactly plane wave for their largest drivers.
Mmmhhhh, we are in an open diy forum here and not in a vendor forum.I working in pro FEA on supercomputer, of course I know where it is... my specialty in audio is wavefront propagation and his behavior.
And I made phase plug too so...
The only things I show/will show is the external as on my website.
Bi-radial horns are just narrower vertically when X-Shape is at 60° constant vertically, so it's a different type of listening, there is also a different way to distribute energy, inside the +/- 6dB, energy is stage a little bit differently with fins (with no accidents in my design).
Usually I said if you listen some time sit down and sometime you move and your are stand up making other things, take X-Shape, otherwise the bi-radial is interesting too, but it's not related to fins at all, it's related to vertical directivity.
But I don't said it's the better horn, I have a client at the US (New York) that have bought one pair of X-Shape X41 and one of bi-radial mk2, for the pleasure to test, with 18Sound ND3, 18Sound 15NTLW3500 as woofer bellow and 18NLS4000 as subs, Hypex Ncore Amp and miniDSP Flex HTX as DSP/pre-amp.
You do not disclose impedance measurements for your horns here.
You do not disclose distortion measurements for your horns here.
You do not show real life driver polar measurements here.
You do not disclose pictures of the throat entry section here.
But you say that customers buy your devices just for the pleasure of test.
I have a different understanding of give and take in a discussion.
It's not only the shape of the wavefront but also its intensity distribution, both are equally important. What the fins do is they take the wavefront and separate its different regions (which would otherwise tend to average out), and "magnify" these little differences to a much larger area down the horn. Relative to wavelengths involved, this is seldom a good thing to do. For this to work well you would need a perfect wavefront, or at least nearly perfect, which is far from reality, unfortunately. It's mainly because the compression cavity is a terrible place to create a uniform sound source to begin with.
Yes not exactly plane but plane enough to be predictable, when not in break-up as already said.
You do not disclose impedance measurements for your horns here. => dependent of driver and always plane in almost every horn whatever you do, Kolbrek book again
You do not disclose distortion measurements for your horns here. => depending on driver and EQ and there is test 1" and 1.4" on X-Shape on my web site with each polar.
You do not show real life driver polar measurements here. => my polar ARE real life polar, all, with VituixCAD in Half Space selected and -6dB on the Yellow, the best one to see all possibles default, the more honest possible.
What is this ? You try to fool people saying it's simulated ? it's real polar !
You do not disclose pictures of the throat entry section here. => no, and I will not, you have missed something and I will not help you, there is a chasm between BEM and pro FEA, do you will paid the kW of electricity + time of the super computer ? no, so accept that there is others method, closer to what does big brands, to resolve problematics.
But you say that customers buy your devices just for the pleasure of test. => He see the real polar on the webiste, use an X41 that is the best horn that he have listening and used (and it's not a beginner at all...) and want to listen the bi-rad mk2, he will be in my house seen his own horn before shipping in few days, it's call trust based on real technical, real polar and human characteristics apparently...
Agree on ESxxx
Yes it separate the wavefront but at the origin the fins was there to maintain the hypex law of surface with constant directivity in H, later we disover that the energy distribution was different inside the +/-6dB, we agree on this mabat, for the rest, well, there is things that can be do, just by looking the picture of the mk1 version some things are obvious but well...
Again my real polar speaks on themself with comparison to Arai on TH4001
For the discussion I'm here only decause DIY readers ask me to come to see your response and feel that it need precision as you may have no understand everything properly.
For the Mk2 it will be publish when it's ready, soon.
You do not disclose impedance measurements for your horns here. => dependent of driver and always plane in almost every horn whatever you do, Kolbrek book again
You do not disclose distortion measurements for your horns here. => depending on driver and EQ and there is test 1" and 1.4" on X-Shape on my web site with each polar.
You do not show real life driver polar measurements here. => my polar ARE real life polar, all, with VituixCAD in Half Space selected and -6dB on the Yellow, the best one to see all possibles default, the more honest possible.
What is this ? You try to fool people saying it's simulated ? it's real polar !
You do not disclose pictures of the throat entry section here. => no, and I will not, you have missed something and I will not help you, there is a chasm between BEM and pro FEA, do you will paid the kW of electricity + time of the super computer ? no, so accept that there is others method, closer to what does big brands, to resolve problematics.
But you say that customers buy your devices just for the pleasure of test. => He see the real polar on the webiste, use an X41 that is the best horn that he have listening and used (and it's not a beginner at all...) and want to listen the bi-rad mk2, he will be in my house seen his own horn before shipping in few days, it's call trust based on real technical, real polar and human characteristics apparently...
Agree on ESxxx
Yes it separate the wavefront but at the origin the fins was there to maintain the hypex law of surface with constant directivity in H, later we disover that the energy distribution was different inside the +/-6dB, we agree on this mabat, for the rest, well, there is things that can be do, just by looking the picture of the mk1 version some things are obvious but well...
Again my real polar speaks on themself with comparison to Arai on TH4001
For the discussion I'm here only decause DIY readers ask me to come to see your response and feel that it need precision as you may have no understand everything properly.
For the Mk2 it will be publish when it's ready, soon.
It is not the first time that you claim others may have not have understand something properly. It is kind of blocking a further discussion while keeping certain facts disclosed. @oltos is considering a bunch of different horns/wg for his future setup. So he asked about your design and I suggested him to ask you some distinct questions to ***** of your horn fits his design requirements. sfaik he mentioned somewhere a crossover region around 500Hz (a challenging objective). I do not see your published horn wrt this xover. The roll-off of JBL2451SL SPL below 550Hz is imo not appropriate. All other drivers you showed at your site roll-off at the same point so it is a function of the horn. I asked for distortion figures and impedance shots for these drivers with your horn but you don't want to show them here. Those data would not disclose your design but they are essential to integrate the combined system driver/horn into a speaker system.
If you would have read my post carefully you may have noticed the word "here" occurring several times. For a good reason it is practice to attach pictures in a thread itself. This enables all readers, also years later, to follow and understand the discussion.
Btw, a driver break-up itself in a horn without fins has almost no to less effect on directivity. Directivity control is a sole function of the horn. And concerning my JBL 2450SL aquaplus drivers have very controlled behaviour up to about 18k. I cannot detect any relevant break-up modes for my drivers below that. Maybe your copies have no aquaplus or may be defect.
What I do not understand is that you point on your super computer calculations. I know what this is as I burned way more super computer time for quantum chemical calculations as you probably will ever be able to get in your life but it is no argument in a discussion using a super computer. In the end it is always only to make a model and use a method and get a results regardless of using a pc or super computer. wrt the results you need to know the restrictions of model and method.
@NicoB
I have indeed an issue to understand what you intend to say with this which is taken from your site:
https://audiohorn.net/next-gen-bi-radial-horn/
Could you elaborate on this? What are the two constant 90° horns you refer to? Btw, a constant horn is per definition constant...
I have indeed an issue to understand what you intend to say with this which is taken from your site:
https://audiohorn.net/next-gen-bi-radial-horn/
Could you elaborate on this? What are the two constant 90° horns you refer to? Btw, a constant horn is per definition constant...
you right a tool is a tool and only final result mater, but I maintain that you said about crossover is wrong (it's GD that have to be look, after EQ it flat), and of course it's not simulate polar on my website...
The mk1 (that is replaced) is actually crossed at 700hz with 15" by pro.
For the rest I have already explain it and it's on my website and here, and yes I know apex and a lot of horn's behavior thanks to FEA, same for Kolberk, Cinnani, Nielsen...
No "Constant" is not enough for some acousticians, they will ask you, "yes constant but at -3db ? -6db perfectly too ? -12 db too ?", it's really what happens.
It's where fins change the stage of energy, if you look the polar of a good fins horn you will see that it stay constant at a lower energy, in relative.
There is a difference between fins horn and other horn about this whatever the design, we can said that is because technically it's act a multiple close to each other horns in a way (I don't remember who said it first, Arai show it in his book may be), the game is then to see the wavefront and to making evolving/tune the principle to have what you want.
The mk1 (that is replaced) is actually crossed at 700hz with 15" by pro.
For the rest I have already explain it and it's on my website and here, and yes I know apex and a lot of horn's behavior thanks to FEA, same for Kolberk, Cinnani, Nielsen...
No "Constant" is not enough for some acousticians, they will ask you, "yes constant but at -3db ? -6db perfectly too ? -12 db too ?", it's really what happens.
It's where fins change the stage of energy, if you look the polar of a good fins horn you will see that it stay constant at a lower energy, in relative.
There is a difference between fins horn and other horn about this whatever the design, we can said that is because technically it's act a multiple close to each other horns in a way (I don't remember who said it first, Arai show it in his book may be), the game is then to see the wavefront and to making evolving/tune the principle to have what you want.
No, I did not say that. There was only a recommendation how I would use your horn that has been published. Maybe 900 to 1k crossover but @oltos mentioned a much lower point. The old rule of thumb is about one octave headroom and this is still my design objective as I am using passive crossover with a similar order than the old TAD designs and I prefer lowest distortions
GD is not enough to look at. Distortions are important too. You need to take driver "out of the game" when distortions become worse. I should tat region for my wn300alo horn.
btw, @mabat has shown numerous times that fins are not mandatory to yield nicely constant behavior together with a very broad dispersion.
The fins do less wrt constant directivity except they help a little in the upper 1.5 octaves and mitigate midrange narrow. In the collaboration with donvk and fluid I created a lot of different fin horns. The task was always to first optimize the horn profile without fins. You will be surprised how small the effect is when adding the fins. The effect on loading is substantial. So I suggest that you enhance your understanding about the contribution of fins. The main purpose is to preserve loading as compared to an exponential profile you only cur away material from the outer profile to make it almost straight and distribute it on the section wise apex of the wf (or an assumption of it) and divide this by the number of fins.
Here is one of the variants without fins:
Now you need a very detailed understanding what the fins change wrt this polar. This example is an almost perfect behavior before adding the fins.
The fins do less wrt constant directivity except they help a little in the upper 1.5 octaves and mitigate midrange narrow. In the collaboration with donvk and fluid I created a lot of different fin horns. The task was always to first optimize the horn profile without fins. You will be surprised how small the effect is when adding the fins. The effect on loading is substantial. So I suggest that you enhance your understanding about the contribution of fins. The main purpose is to preserve loading as compared to an exponential profile you only cur away material from the outer profile to make it almost straight and distribute it on the section wise apex of the wf (or an assumption of it) and divide this by the number of fins.
Here is one of the variants without fins:
Now you need a very detailed understanding what the fins change wrt this polar. This example is an almost perfect behavior before adding the fins.
@oltos
The best what I can suggest to you wrt the thread title is to use the Yuichi design but with the different fin orientation we used for the mk3b2. This should not be so hard to realize for any of the clone makers. Maybe you could ask @fluid for the CAD files. I cannot remember if he attached the files here in the forum.
The best what I can suggest to you wrt the thread title is to use the Yuichi design but with the different fin orientation we used for the mk3b2. This should not be so hard to realize for any of the clone makers. Maybe you could ask @fluid for the CAD files. I cannot remember if he attached the files here in the forum.
Strange the kind of diffraction after 6kHz but this is that allow to be constant upper apparently.
About this and constant aspect at -3/-6/-12 dB, I don't said that it need to be constant at -12dB at all but -3dB is very important to be clean and regular as it's generally this that early reflection will sent to the listener in a room (sides walls).
The diffraction can be avoid in all design but may be it's due to 2" throat, if it's a 2" throat horn, I don't know.
The aspect "partially hyper constant" can be only found with fins, but again I don't said it's better or whatever, I use both with and without fins horns, I haven't any religion about it but all my designs are free of diffraction by nature 😀.
About this and constant aspect at -3/-6/-12 dB, I don't said that it need to be constant at -12dB at all but -3dB is very important to be clean and regular as it's generally this that early reflection will sent to the listener in a room (sides walls).
The diffraction can be avoid in all design but may be it's due to 2" throat, if it's a 2" throat horn, I don't know.
The aspect "partially hyper constant" can be only found with fins, but again I don't said it's better or whatever, I use both with and without fins horns, I haven't any religion about it but all my designs are free of diffraction by nature 😀.
For the JBL 2450SL aquaplus (that is "aquaplus" the blue treatment ? I don't remember what is after the "aqua"), I have the same driver :
It still a good compression driver, I have it too and appreciate it but the breakup begin seriously at 9khz and show sign at 5kHz.
It's why she begin to act a little bit on herself after 9khz in a horn (like "shaking"), if we compare to others one, the plane wave radiation is not more plane wave.
It still a good compression driver, I have it too and appreciate it but the breakup begin seriously at 9khz and show sign at 5kHz.
It's why she begin to act a little bit on herself after 9khz in a horn (like "shaking"), if we compare to others one, the plane wave radiation is not more plane wave.
This was pre-optimization step before adding the fins as I wrote so putting lines here to show anything is meaningless.
yes a dark blue, I have the same, well in your burst the breakup is hidden, outside scale, look :
I thinks you can see it with your horn, put your mic at 0cm of the mouth and EQ the driver flat until 20kHz, then you will see the same basically 👍
I thinks you can see it with your horn, put your mic at 0cm of the mouth and EQ the driver flat until 20kHz, then you will see the same basically 👍
This is all I get out of this SW:
This is an excellent sounding driver. If there are any break-up modes, they do not harm imo.
This is an excellent sounding driver. If there are any break-up modes, they do not harm imo.
Actually, when comparing my Altec 416 to what presumably is a very similar 15” ElectroVoice woofer (see attached T/S parameters if this helps), Weltersys seems to predict that it will be free of beaming as high as 1kHz, yielding 90 degrees coverage; see posts # 185, 205. Thanks to Weltersys for this comparison.
So while Troy Crowe’s measurements do site 500Hz as ideal, that range in between does not appear problematic.
Nice view, could you measure EQ flat until 20kHz at high volume and not just selected "relative" ?
As if you use only relative alone a part of the information have disappear in the room's noise, as the driver goes down in HF naturally, thanks 😀.
Yes after 10k it not harm, I like this driver to of course.