Re: Re: Re: Question for David
Hi Eva,
I agree that it would be great if Hornresp could do all sorts of other things - unfortunately I have to draw the line somewhere, otherwise I would be working on the program 24/7
. I will nevertheless keep your suggestion in mind for the future - thanks.
Note that the current phase response chart only shows the phase shift through the driver itself, not down the horn as well.
Kind regards,
David
Eva said:
Hi Eva,
I agree that it would be great if Hornresp could do all sorts of other things - unfortunately I have to draw the line somewhere, otherwise I would be working on the program 24/7
. I will nevertheless keep your suggestion in mind for the future - thanks.Note that the current phase response chart only shows the phase shift through the driver itself, not down the horn as well.
Kind regards,
David
Eva said:
Hi Eva,
There is more to life than money
.To be perfectly honest, in the past I have really only added things to Hornresp that required me to learn something new - the tapped horn simulation model is a good recent example of that. The problem I now face is that a lot of the requests I receive are for enhancements that do not require me to gain new knowledge, so that the motivation to upgrade the program is not as strong.
Also, to do some of the new things properly would really require a total revision of the Hornresp platform and the (originally DOS-based) user interface. Unfortunately, I simply do not have the time or enthusiasm to undertake such a major re-build. It has taken me thousands of hours to get Hornresp to where it currently is - I have been working on the program in one form or another for over thirty years.
Perhaps I am just getting old and tired...
.Kind regards,
David
Horn phase response in the crossover region is a very interesting subject. Impedance peaks and the usually sharp LF roll-off result in gentle and wild phase shifts, sometimes over 180 degrees "p-p". I have done measurements but the software is weak (again!) when it comes to produce meaningful phase plots.
On the other hand, multi-way systems involving one or more horns without phase matching in the crossover region produce a typical horn-sound signature: Some frequencies are summing strong on-axis, others are summing only off-axis and others are just disappearing, and all this happens within only one octave or two. Optimum polarity or plain delay can produce some improvement but can't solve the problem.
Phase matching is much more important than an inherently flat SPL response, it is the key to get hi-fi sound from horns, and it is achieved by placing parametric EQs at the right frequencies with a DSP crossover. SPL response may be corrected later with a graphic EQ (which responds much better after matching).
The process of adjusting the parametric EQs by ear becomes quite easy if you have the tools to do some previous analysis and you know how many "positive" and "negative" bumps you have to flatten and their order. It becomes very hard if you don't have that data.
That's why I'm asking for meaningful phase plots.
If the the current plot is not including the horn, then, does it serve any purpose? I think it doesn't. Everybody using the program is expecting to get a phase plot modelled at the same place where SPL plot is. It's more like fixing a bug than like adding a feature.
On the other hand, multi-way systems involving one or more horns without phase matching in the crossover region produce a typical horn-sound signature: Some frequencies are summing strong on-axis, others are summing only off-axis and others are just disappearing, and all this happens within only one octave or two. Optimum polarity or plain delay can produce some improvement but can't solve the problem.
Phase matching is much more important than an inherently flat SPL response, it is the key to get hi-fi sound from horns, and it is achieved by placing parametric EQs at the right frequencies with a DSP crossover. SPL response may be corrected later with a graphic EQ (which responds much better after matching).
The process of adjusting the parametric EQs by ear becomes quite easy if you have the tools to do some previous analysis and you know how many "positive" and "negative" bumps you have to flatten and their order. It becomes very hard if you don't have that data.
That's why I'm asking for meaningful phase plots.
If the the current plot is not including the horn, then, does it serve any purpose? I think it doesn't. Everybody using the program is expecting to get a phase plot modelled at the same place where SPL plot is. It's more like fixing a bug than like adding a feature.
Hy David,
Do you happen to have a changelog? I´ve been following changes for some time and dokumenting them whenever I see something. But due to beeing occupied in my job I lost track since November last year.
Thanx again for this very nice peace of software. I build a few TH and hornresp helps a lot everytime
Do you happen to have a changelog? I´ve been following changes for some time and dokumenting them whenever I see something. But due to beeing occupied in my job I lost track since November last year.
Thanx again for this very nice peace of software. I build a few TH and hornresp helps a lot everytime
Sabbelbacke said:
Hi Sabbelbacke,
A copy of the Hornresp Version History list follows. Coincidentally, just today I have released a minor update (Ver 17.10). The Combined Response Tool can now show either the combined response, or just the "rear-side" direct radiator / port output. My thanks to Eva for suggesting this enhancement.
Kind regards,
David
///////////////////////////////////
HORNRESP VERSION HISTORY
Version 1.00 - First release.
Version 1.10 - Support for all standard international number settings.
Version 1.20 - Sound pressure on axis at one metre rather than at horn mouth.
Version 1.30 - Thiele-Small parameter converters for Bl and Rms.
Version 1.40 - SPL response chart comparison.
Version 1.50 - Help print.
Version 2.00 - Tractrix.
Version 2.10 - Sensitivity model changed.
Version 2.20 - Export frequency response data.
Version 3.00 - Salmon's family hyperbolic-exponential.
Version 3.10 - Schematic diagram.
Version 3.20 - Tractrix model changed.
Version 3.30 - Vrc units from cc to litres.
Version 4.00 - Isophase wavefront option for Salmon's family.
Version 4.10 - Conical, hyperbolic-exponential and tractrix wizard tool.
Version 4.20 - Thiele-Small parameter converter for Mmd.
Version 4.30 - Isophase wavefront model changed.
Version 5.00 - Converted to multiple-document interface (MDI).
* Electrical impedance and diaphragm displacement charts.
* Horn mouth acoustical impedance model changed.
* Chart frequency range extended down to 10 hertz.
* Automatic scaling of chart Y-axis.
* Horn and chart data exported.
* Air chamber resonance masking.
* Variable input signal voltage.
* Optional saving of record changes.
Version 5.10 - Options tool.
Version 5.20 - Sensitivity model changed.
Version 5.30 - Find tool.
* Diaphragm displacement chart comparison.
* Range tool.
Version 5.40 - Multiple drivers tool.
Version 5.50 - Eg parameter calculator.
* Automatic selection of wavefront model.
* Multiple speakers tool.
Version 5.60 - Tractrix model changed.
* Universal data file.
Version 5.70 - Find tool changed.
Version 5.80 - Diaphragm displacement model changed.
Version 6.00 - Phase response chart.
Version 6.10 - Electrical impedance chart comparison.
Version 6.20 - Hypex designer tool.
Version 6.30 - Specify Cir or Fta option added to wizard tool.
* Zoom option added to range tool.
Version 7.00 - Directivity and pattern tools.
* Horn cross-section height and width data exported.
Version 7.10 - Directivity model changed.
Version 7.20 - Install on any drive.
Version 7.30 - Multiple speakers model changed.
Version 7.40 - Support for all standard Windows display settings.
* Far-field response for multiple speakers.
Version 7.50 - System volume specified on schematic diagram.
Version 8.00 - SPL response and directivity models changed.
Version 8.10 - Back horn tool.
* Phase response model changed.
Version 8.20 - Sort tool.
Version 8.30 - Group delay chart.
Version 8.40 - Acoustical impedance chart comparison.
* Captured results comparison option.
Version 8.50 - System design tool.
* Thiele-Small parameter calculator.
* J1 and K1 Fortran algorithms.
Version 9.00 - Oblate spheroidal waveguide.
Version 10.00 - Spherical horn.
Version 11.00 - Vented rear chamber.
Version 12.00 - Wavefront simulator tool.
Version 13.00 - Beam width tool.
* Maximum SPL tool.
Version 14.00 - Rg and Nd.
* File and tools menus changed.
Version 15.00 - Tapped horn.
* 20 KHz data exported.
* Constant 4 Pi area.
Version 16.00 - Combined response model changed.
* Infinite tapped horn.
Version 16.10 - Tapped horn wizard tool.
Version 16.20 - Tapped horn wavefront simulator.
Version 16.30 - Copy and paste driver parameter values.
Version 16.40 - Mass-loaded horn.
* Negative conical flare.
Version 17.00 - Le Cléac'h horn.
Version 17.10 - Combined response rear output only.
///////////////////////////////////
Attachments
Thank you very much David. I find this new feature quite useful to model rear loaded horns. I'm getting headaches trying to cross over some good old JBL 4520 super scoopers with mid horns. I may get a better understanding about where the horn (with its 220cm delay) dominates and where the 15" inch drivers (with no delay) dominate. Phase response is wild.
David McBean: Hi David, first thanks you for the latest update of Hornresp, another useful feature, and a very impressive list of revisions.
As Eva has been so successful - - I have another request too, it pertains to the tapped horn:
The Danley patent - as referenced by Marcello in the collaborative tapped horn thread - shows the inside of the TOP in Fig.8 and Fig.9. The same construction method seems to have been applied
to the DTS-20.
The sequence of the forward acoustic flow is:
- driver front
- compression chamber
- horn throat
- horn run driver front to back
- horn run driver back to mouth.
There is no S1 to S2 section.
From the photographs of the inside of the DTS-20 it is obvious, that at least two resonance pipes are being employed.
At present this tapped horn configuration cannot be modeled in Hornresp. Is there any hope for adding at least the front compression chamber, e.g.: in front of the S1 to S2 section, with the respective relocation of the driver to S1 when this feature is used? I realize, that it is possible to minimize the impact of the S1 to S2 section in the current model, but with such a fine piece of software that just about makes me cringe.
Not being a programmer, I have no real idea of what I just asked, and I should probably find some early morning hours to learn how to use AkAbak.........
Thanks again, bye for now.
As Eva has been so successful -
- I have another request too, it pertains to the tapped horn:The Danley patent - as referenced by Marcello in the collaborative tapped horn thread - shows the inside of the TOP in Fig.8 and Fig.9. The same construction method seems to have been applied
to the DTS-20.
The sequence of the forward acoustic flow is:
- driver front
- compression chamber
- horn throat
- horn run driver front to back
- horn run driver back to mouth.
There is no S1 to S2 section.
From the photographs of the inside of the DTS-20 it is obvious, that at least two resonance pipes are being employed.
At present this tapped horn configuration cannot be modeled in Hornresp. Is there any hope for adding at least the front compression chamber, e.g.: in front of the S1 to S2 section, with the respective relocation of the driver to S1 when this feature is used? I realize, that it is possible to minimize the impact of the S1 to S2 section in the current model, but with such a fine piece of software that just about makes me cringe.
Not being a programmer, I have no real idea of what I just asked, and I should probably find some early morning hours to learn how to use AkAbak.........
Thanks again, bye for now.
G'day tb46
There is essentially no compression chamber in the front of the DTS-20 driver as shown in the image in the patent, only the volume taken by the cone, perhaps 1Liter. With a model for this, just make your start area very small (1cm^2) and expand to your throat size in a distance that gives you the same volume as that contained in the cone. This should get you very close.
The resonant pipes will be hard to model, this should be done with trial and error. The length of the pipes adjusts their resonant frequency and the amount of fill in them will adjust the 'Q' and also the resonant frequency, because the fill will slow down the speed of sound in the pipe.
Cheers
William Cowan
There is essentially no compression chamber in the front of the DTS-20 driver as shown in the image in the patent, only the volume taken by the cone, perhaps 1Liter. With a model for this, just make your start area very small (1cm^2) and expand to your throat size in a distance that gives you the same volume as that contained in the cone. This should get you very close.
The resonant pipes will be hard to model, this should be done with trial and error. The length of the pipes adjusts their resonant frequency and the amount of fill in them will adjust the 'Q' and also the resonant frequency, because the fill will slow down the speed of sound in the pipe.
Cheers
William Cowan
cowanaudio: Hi William, I guess I should have posted this in the collaborative TH thread.
I have been using the work-around you are describing for a while, and it is good to know that from your experience it gives good results. I've mentioned resonant pipes, helmholz resonators and filters for a while at the TH thread, but there was no interest until people saw the pictures of the inside of the DTS-20, oh well. There should be a way to include these in a model, but, it may take AkAbak to do it.
Thanks for your great site. Bye for now.
I have been using the work-around you are describing for a while, and it is good to know that from your experience it gives good results. I've mentioned resonant pipes, helmholz resonators and filters for a while at the TH thread, but there was no interest until people saw the pictures of the inside of the DTS-20, oh well. There should be a way to include these in a model, but, it may take AkAbak to do it.
Thanks for your great site. Bye for now.
Or maybe some of us showed no interest in the hope of protecting TD's intellectual property for as long as practical since there's folks that wouldn't think twice about using it for personal gain before his patent was granted.......
Anyway, he's publicly stated that it can be modeled in Akabak.
GM
Anyway, he's publicly stated that it can be modeled in Akabak.
GM
Hi GM: Good point. As far as I'm concerned I have already passed on the information about Tom's company and their product to an interested party, and I think he is delivering a great product at a very fair price. Once he has placed his patent applications he should be reasonably protected, I hope.
Hi David
I have managed to put together an accurate phase measurement setup by feding to the line input of my laptop both a sample of the signal being fed to the speaker and the signal from the measurement microphone preamplifier. Analyzer software does the rest.
The results are a bit puzzling. In few words: Horn group delay is neither constant across the passband nor related directly to horn lenght.
I measured one bass, one midrange and one tweeter horn. Only the group delay of the bass horn matched its lenght in the middle of the passband, but it became progressively lower for low frequencies and higher for high frequencies. Also, the bass horn exhibited quite different resonant modes than Hornresp would predict (I will investigate further on this). Midrange horn exhibited similar behaviour, but mid-band group delay was approx. 45cm as opposed to the 35cm path length. Tweeter horn was quite similar with 32cm mid-band group delay as opposed to 21cm path length. In all cases, group delays in the lower crossover region were similar or shorter than path length while group delays in the upper crossover region were higher than path length (even two times higher).
I have managed to put together an accurate phase measurement setup by feding to the line input of my laptop both a sample of the signal being fed to the speaker and the signal from the measurement microphone preamplifier. Analyzer software does the rest.
The results are a bit puzzling. In few words: Horn group delay is neither constant across the passband nor related directly to horn lenght.
I measured one bass, one midrange and one tweeter horn. Only the group delay of the bass horn matched its lenght in the middle of the passband, but it became progressively lower for low frequencies and higher for high frequencies. Also, the bass horn exhibited quite different resonant modes than Hornresp would predict (I will investigate further on this). Midrange horn exhibited similar behaviour, but mid-band group delay was approx. 45cm as opposed to the 35cm path length. Tweeter horn was quite similar with 32cm mid-band group delay as opposed to 21cm path length. In all cases, group delays in the lower crossover region were similar or shorter than path length while group delays in the upper crossover region were higher than path length (even two times higher).
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