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Old 9th January 2011, 12:11 AM   #1571
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Hey while I' thinking about it I have something to ask about.

What is the difficulty in making an area where we could do horns with multiple taps alla unity type horns. I have been working on a few.

And I'm just a little bit tired of that byzantine nightmare called AKaBak. I have hardly any hair left to pull out!

If I don't ask I don't get.

I probably won't get but you know...

Even the hardest rocks get warn away by soft water...
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Old 9th January 2011, 07:54 AM   #1572
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Originally Posted by pk View Post
I would like to know how to use HornResp to match the dispersion at the crossover point (e.g. 1300 Hz) between, say, a non CD mid horn and a non CD tweeter horn. For instanse, if I have a LeCleach flared or tractrix flared mid circular horn with a Fc=200 Hz, then how do I "see" the dispersion at different frequencies?
Hi Peter,

If you are referring to acoustic dispersion in the strictest sense, then I don't think that Hornresp can help you much. If however you simply want to check the directivity characteristics of a particular speaker over a given frequency range, then Tools > Directivity > Beam Width and Tools > Directivity > Polar Map would be good places to start (bearing in mind that the Hornresp directivity models are indicative only).

Kind regards,

David
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Old 9th January 2011, 08:10 AM   #1573
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Quote:
Originally Posted by mwmkravchenko View Post
What is the difficulty in making an area where we could do horns with multiple taps alla unity type horns.
Hi Mark,

This feature has been requested before by others, and unfortunately the answer has to remain the same. The Hornresp user input interface would require significant modification and many coding changes to accommodate the additional functionality. I am not in a position to do this.

Sorry, but AkAbak is your only option :-).

Kind regards,

David
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Old 9th January 2011, 10:32 AM   #1574
pk is offline pk  Denmark
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Hi David,

Thanks a lot for your reply! I will try what you suggest and then eventually get back

Best regards
Peter


Quote:
Originally Posted by David McBean View Post
Hi Peter,

If you are referring to acoustic dispersion in the strictest sense, then I don't think that Hornresp can help you much. If however you simply want to check the directivity characteristics of a particular speaker over a given frequency range, then Tools > Directivity > Beam Width and Tools > Directivity > Polar Map would be good places to start (bearing in mind that the Hornresp directivity models are indicative only).

Kind regards,

David
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Old 9th January 2011, 10:52 AM   #1575
pk is offline pk  Denmark
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Default Directivity - sanity check

Hi David,

I used HornResp to simulate the beamwidth of a 200 Hz LeCleach flared horn (see attachment). One question in order to check whether I understand this right:

Let's say I wanted to build a conical tweeter horn to match the 200 Hz LeCleach horn at 1500 Hz (crossover point), then - if I understand the simulation correct - I should build a conical horn with 60 degrees dispersion for the tweeter.

Or alternatively, if I wanted to build a conical tweeter horn to match the dispersion of the 200 Hz LeCleach mid horn at 900 Hz (crossover point), then the dispersion of the conical horn should have 80 degree dispersion.

Am I correct?

Thanks a lot!

Best regards
Peter



Quote:
Originally Posted by David McBean View Post
Hi Peter,

If you are referring to acoustic dispersion in the strictest sense, then I don't think that Hornresp can help you much. If however you simply want to check the directivity characteristics of a particular speaker over a given frequency range, then Tools > Directivity > Beam Width and Tools > Directivity > Polar Map would be good places to start (bearing in mind that the Hornresp directivity models are indicative only).

Kind regards,

David
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File Type: jpg Beam width for 200 Hz LeCleach horn.JPG (75.8 KB, 311 views)
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Old 10th January 2011, 04:57 AM   #1576
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Originally Posted by pk View Post
Am I correct?
Hi Peter,

You are interpreting the Hornresp Beam Width chart correctly. For the example you have given, at 1500 Hz and 30 degrees off-axis (60 degrees beam width), the SPL is down 6 dB from its value on axis. Similarly, at 900 Hz the SPL is down 6 dB from its on-axis value at an angle 40 degrees off-axis (80 degrees beam width).

Note that all four Hornresp directivity charts are inter-related. To illustrate, I have attached the results for a 160Hz Le Cléac'h horn with T = 0.80.

1. From the Beam Width chart you can see that the -6 dB beam width at 1000 Hz is 67.1023 degrees. For the purpose of the exercise we will assume that the beam width is actually 68 degrees, equivalent to an off-axis angle of 34 degrees.

2. Now look at the 1000 Hz directivity pattern. The "-6 dB beam" is given as 67.1 degrees, which is consistent with the value obtained in 1 above. 34 degrees off-axis the SPL is down 6.2 dB from the on-axis value. This is also consistent with the earlier result - the value would be exactly -6 dB if we could sample at precisely the half-beamwidth angle, rather than at the 34 degree approximation.

3. The attached SPL response chart compares the response 34 degrees off-axis (black trace) to the on-axis response (gray trace). At 1000 Hz the off-axis response is 6.2 dB down, consistent with the value obtained in 2 above. At 1000 Hz and 34 degrees off-axis the SPL is 107.7433 dB.

4. If you now check the polar map, you will see that at 1000 Hz and an off-axis angle of 34 degrees, the SPL is 107.74 dB, the same value (rounded to two decimal places) as given in 3 above.

Hope this helps to clarify the Hornresp directivity results.

Kind regards,

David
Attached Images
File Type: png Beamwidth.png (24.8 KB, 282 views)
File Type: png Pattern.png (21.0 KB, 283 views)
File Type: png Response.png (27.8 KB, 278 views)
File Type: png Polarmap.png (47.5 KB, 274 views)
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Last edited by David McBean; 10th January 2011 at 05:05 AM.
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Old 10th January 2011, 05:35 AM   #1577
pk is offline pk  Denmark
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Hi David,

Thanks a lot for your thorough and clear reply!

Best regards
Peter


Quote:
Originally Posted by David McBean View Post
Hi Peter,

You are interpreting the Hornresp Beam Width chart correctly. For the example you have given, at 1500 Hz and 30 degrees off-axis (60 degrees beam width), the SPL is down 6 dB from its value on axis. Similarly, at 900 Hz the SPL is down 6 dB from its on-axis value at an angle 40 degrees off-axis (80 degrees beam width).

Note that all four Hornresp directivity charts are inter-related. To illustrate, I have attached the results for a 160Hz Le Cléac'h horn with T = 0.80.

1. From the Beam Width chart you can see that the -6 dB beam width at 1000 Hz is 67.1023 degrees. For the purpose of the exercise we will assume that the beam width is actually 68 degrees, equivalent to an off-axis angle of 34 degrees.

2. Now look at the 1000 Hz directivity pattern. The "-6 dB beam" is given as 67.1 degrees, which is consistent with the value obtained in 1 above. 34 degrees off-axis the SPL is down 6.2 dB from the on-axis value. This is also consistent with the earlier result - the value would be exactly -6 dB if we could sample at precisely the half-beamwidth angle, rather than at the 34 degree approximation.

3. The attached SPL response chart compares the response 34 degrees off-axis (black trace) to the on-axis response (gray trace). At 1000 Hz the off-axis response is 6.2 dB down, consistent with the value obtained in 2 above. At 1000 Hz and 34 degrees off-axis the SPL is 107.7433 dB.

4. If you now check the polar map, you will see that at 1000 Hz and an off-axis angle of 34 degrees, the SPL is 107.74 dB, the same value (rounded to two decimal places) as given in 3 above.

Hope this helps to clarify the Hornresp directivity results.

Kind regards,

David
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Old 11th January 2011, 05:52 PM   #1578
vadi is offline vadi  Austria
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Hi, can I use Hornresp to calculate the SPL response of a driver without a baffle?
I just read about it on Audiocircles forum (scorpion's post) and the results seem to be higher than from Linkwitz's spreadsheet - not that I would be against this.

Click the image to open in full size.
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Last edited by vadi; 11th January 2011 at 05:55 PM.
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Old 12th January 2011, 10:51 PM   #1579
vadi is offline vadi  Austria
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Quote:
Originally Posted by vadi View Post
Hi, can I use Hornresp to calculate the SPL response of a driver without a baffle?
I just read about it on Audiocircles forum (scorpion's post) and the results seem to be higher than from Linkwitz's spreadsheet - not that I would be against this.

Click the image to open in full size.
Sorry, it's closed box response.
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Old 13th January 2011, 07:58 AM   #1580
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Originally Posted by vadi View Post
Hi, can I use Hornresp to calculate the SPL response of a driver without a baffle?
Hi vadi,

Yes you can, by setting Ang = 4.0 x Pi, S1 = Sd, S2 = Sd and L12 (Con) = 0.01. Note that the 'combined response' SPL will be very low because the signals from the front and rear sides of the diaphragm are almost 180 degrees out of phase, resulting in nearly perfect cancellation.

Kind regards,

David
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Last edited by David McBean; 13th January 2011 at 08:06 AM.
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