Possible Problem w/ V.2870-110816
Hi David,
After installing the newest version (2870-110816) I encountered the following problem:
Some files saved with BR or ND come up as TH.
(OD files come up as OD. CH come up as CH. TH come up as TH.)
Warning: Once the new version is installed, and has been run, the data file cannot be opened with a previous version.
I had an older version (2830-110124) installed under a different name (Hornresp2), and it still functions just fine.
Regards,
Hi David,
After installing the newest version (2870-110816) I encountered the following problem:
Some files saved with BR or ND come up as TH.
(OD files come up as OD. CH come up as CH. TH come up as TH.)
Warning: Once the new version is installed, and has been run, the data file cannot be opened with a previous version.
I had an older version (2830-110124) installed under a different name (Hornresp2), and it still functions just fine.
Regards,
OK, what is the advantage of having the driver see a resistive load? Does it increase efficiency or something? Do direct radiator type of loudspeakers see a resistive load in the free air? Why can't the resonant impedance peak be removed by a notch filter? I have not read the patent but I can do that today.
Resistance dissipates energy, reactance stores it. By increasing the resistance compared to the reactance, you increases efficiency. Reactance anulling increases efficiency near the horn cutoff, where the horn load is dominated by the reactance of the air mass, that you just move back and forth.
Direct radiators mainly see a reactive acoustical load; the air mass that the diaphragm moves back and forth. There is a small resistive part there too (the energy dissipated in this acoustical resistance is what you hear as sound), but it is very small compared to the mass reactance. This is the reason for the low efficiency of direct radiators.
A notch filter can fix the electrical impedance peak as seen by the amplifier. It can't do anything with the efficiency of the acoustical coupling between the driver and the horn.
Bjørn
Resistance dissipates energy, reactance stores it. By increasing the resistance compared to the reactance, you increases efficiency. Reactance anulling increases efficiency near the horn cutoff, where the horn load is dominated by the reactance of the air mass, that you just move back and forth.
Direct radiators mainly see a reactive acoustical load; the air mass that the diaphragm moves back and forth. There is a small resistive part there too (the energy dissipated in this acoustical resistance is what you hear as sound), but it is very small compared to the mass reactance. This is the reason for the low efficiency of direct radiators.
A notch filter can fix the electrical impedance peak as seen by the amplifier. It can't do anything with the efficiency of the acoustical coupling between the driver and the horn.
Bjørn
OK, very interesting thanks! I think I have something pretty good with a 100Hz hyp-ex straight horn for my 12PE32 drivers. They are 74cm square by 105cm deep. Of course, I'll need a subwoofer or two....
Hi David,
Just a little more information to the problem I reported in Post #2141: I deleted the Hornresp folder with the newest update (2870-110816), and reinstalled a saved copy of Hornresp. This old version had most of the problem files. Then I updated to 2860-110805, and everything seems to work just like normal. So, as far as I can tell the problem occured between 2860-110805 and the latest greatest.
Regards,
Just a little more information to the problem I reported in Post #2141: I deleted the Hornresp folder with the newest update (2870-110816), and reinstalled a saved copy of Hornresp. This old version had most of the problem files. Then I updated to 2860-110805, and everything seems to work just like normal. So, as far as I can tell the problem occured between 2860-110805 and the latest greatest.
Regards,
Is it possible to simulate a folded horn in your program?
Hi dirkwright,
Yes. Most bass horns simulated in Hornresp are folded designs.
Kind regards,
David
Hi David,
After installing the newest version (2870-110816) I encountered the following problem:
Some files saved with BR or ND come up as TH.
(OD files come up as OD. CH come up as CH. TH come up as TH.)
Warning: Once the new version is installed, and has been run, the data file cannot be opened with a previous version.
I had an older version (2830-110124) installed under a different name (Hornresp2), and it still functions just fine.
Regards,
Hi Oliver,
Thanks for the feedback.
The format of the Hornresp.dat data file was changed with the release of Version 28.70. The existing file should have updated automatically without the user being aware of it. Files so converted are not backwards compatible - hence the warning message.
You indicate that some records saved with BR come up as Nd. Where does BR come from? There should be no BR driver arrangement option
The problem may have something to do with the fact that you are running multiple copies of Hornresp at different version numbers. If you attempt to share a common data file at any stage, then data corruption is likely to occur.
Would it be possible for you to send me a copy of the Hornresp.dat data file that does not convert correctly (before conversion is attempted) so that I can investigate further using your original uncorrupted file. My e-mail address is dmcbean@bigpond.com.
Has anyone else experienced a similar problem to Oliver?
Kind regards,
David
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Hi dirkwright,
Yes. Most bass horns simulated in Hornresp are folded designs.
Kind regards,
David
OK, but I guess what I was getting at is the program doesn't seem to take into account the affects of the folds on the performance of the horn. For example, I've read that folded horns typically do not go as high in frequency response as straight ones. There are losses in the folds, depending on how they are done. More specifically, the size and shape of the corners in the folding are a kind of acoustical filter. Certain frequencies are attenuated and others are allowed to pass. I have read that as the sound wavelengths approach the dimensions of the corners, they become more attenuated. I'm sure it would be very complicated to implement this kind of simulation, but thought I'd just share what I've read about folded horns.
OK, but I guess what I was getting at is the program doesn't seem to take into account the affects of the folds on the performance of the horn. For example, I've read that folded horns typically do not go as high in frequency response as straight ones. There are losses in the folds, depending on how they are done. More specifically, the size and shape of the corners in the folding are a kind of acoustical filter. Certain frequencies are attenuated and others are allowed to pass. I have read that as the sound wavelengths approach the dimensions of the corners, they become more attenuated. I'm sure it would be very complicated to implement this kind of simulation, but thought I'd just share what I've read about folded horns.
I looked around and there is a lot of research in this area, but I'd have to pay to read the articles. Mostly, the research is about wave propagation in pipes.
I looked around and there is a lot of research in this area, but I'd have to pay to read the articles. Mostly, the research is about wave propagation in pipes.
I have some information on my website about how sound waves propagate around horn bends. It might not be exactly what you're looking for, but it's a start.
I have some information on my website about how sound waves propagate around horn bends. It might not be exactly what you're looking for, but it's a start.
Thanks. I'm not really looking to design a folded horn but I find the subject interesting anyway. It would be awesome if David incorporated something like that into Hornresp, though as it stands now it is an incredible service to us to provide such a powerful software package for free. We didn't have this kind of stuff back when I last designed a horn in 1991. I'm really grateful for David's contribution.
I have some information on my website about how sound waves propagate around horn bends. It might not be exactly what you're looking for, but it's a start.
Very interesting article! thank you! Your animations are fascinating. The sound just seems to squish around the corners, sometimes getting confused reflections or just disappearing. It seems to me that folded corners are low pass acoustical filters that add a lot of distortion, but that's just a guess on my part.
http://www.jhsaudio.com/waves.html
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Thanks. Actually bends would probably remove distortion. If they're an acoustical low pass filters, they would attenuate harmonics which are what distortion is. They can definitely have a negative effect on frequency response and polar response at higher frequencies though.
You've got mail.
Thanks Oliver, I will let you know what I find.
Kind regards,
David
would it be possible to see an option to choose a frequency response curve between "Acoustic power" and "Acoustic pressure" like Akabak?
Hi julienb34,
Select the Tools > Directivity > Response... menu command to show the pressure response.
Note that the tool only applies to finite single-segment non-negative flare horns.
You will find that the results are probably different to those generated by AkAbak, which uses a relatively simple directivity model compared to Hornresp.
Kind regards,
David
It would be awesome if David incorporated something like that into Hornresp.
Hi dirkwright,
Sorry, it's not going to happen...
Kind regards,
David
Bug Fix
Hi Oliver,
The bug you found has now hopefully been fixed.
Could you please confirm that your Hornresp_good.dat file converts correctly when opened using Product Number 2870-110818.
Thanks again for all your help!
Kind regards,
David
Thanks Oliver, I will let you know what I find.
Hi Oliver,
The bug you found has now hopefully been fixed.
Could you please confirm that your Hornresp_good.dat file converts correctly when opened using Product Number 2870-110818.
Thanks again for all your help!
Kind regards,
David
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