Hornresp

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#1,325
David_Web said:
But somehow I can no longer export horn data.
Click to expand...

Hi David_Web,

The schematic diagram horn data export bug you identified has now been fixed. The latest release is Product Number 2800-100725. Many thanks for the detailed description of the problem - it made finding the cause that much easier. The problem only occurred with negative flare parabolic segments.

Please note the new Hornresp website address below.

Kind regards,

David
 
#1,330
David, Jean-Michel - this spectrogram feature is smashing !! :up:

skorpion said:
Regarding Hornresp it might be of some interest to point to a simulation of an H-baffle OB with the help of the programme which I posted in the AudioCircle: 15" woofer at 1KHz? .

/Erling
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I'm playing around with Ripol right now and would like to ask for some advice / help in simulating it (if thats the right thread for such).
To get started I checked out your H-Baffle simulation setup at the audiocircel posting and got this results:

hornresp_spectr_1.png


Already pretty good. What can I do to improve for Ripol ?
What I built is a "as compact as it gets" (38x38x42cm) design - a dual 15" box with two Selenium 15PW5 and a "mouth" area of roughly 10x35cm each.

Could you possibly help on my project in setting up a "correct" simu for Ripol speakers?

One thing I noticed is that the spectrogram seems to have different SPL scaling than the SPL plot.
Comparing the difference in SPL from 300Hz and 100Hz its about 30-40dB indicated by the spectrogram whereas its at a more realistic 15dB in the SPL pllot ?


Thanks
Michael
 
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#1,331
Hi Michael,

It was Rudolf's work to simulate H-dipol and Ripol in the AJ-Horn programme that got me interested in what Hornresp could do. In fact with the use of the Compound Horn model it is very easy to set up these models. And I think that the results are valid. H-dipol simus I have compared to MJK's models and the difference is very small.

Here is a Ripole example, which is the same as Rudolf use in his paper in the Download section on his Web: Offene Schallwand (OB) . I think that the pictures tell the story, combined response is calculated with 37 cm difference as in Rudolf's example.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


The Hornresp results are a bit different from Rudolf's and I am no Ripol-expert, so it would be nice if he could comment on them.

/Erling
 
#1,332
Thanks Earling - the link to the new paper of Rudolf in simulating Ripol with AJH is very welcome.

As I see it for now, the Ripol compared to a H-dipole has the additional complexity of closing the radiating area - very much like a front chamber for horns - just the horn omitted.

It should be possible to do that in Hornresp as well.

The other added complexity IMO is that the membrane is not at the "back" of the front chamber but "to the side" (more like the pleats of an AMT configuration) - not knowing if Hornresp simu would be any affected ?

Michael
 
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#1,333
I have simulated the Ripol also with front and back chambers a bit like I did the original H-dipole model. The results have been identical. The Compound Horn model has the intuitive easy understanding coupled to it so I would go for that.

Hornresp is very versatile, in fact you could simulate the now popular baffle-less speakers also.

Perhaps David could comment about the 'mismatch' of membrane surface and hornsegment surface, if that would have any effect on simulations ?

/Erling
 
#1,334
skorpion said:
Perhaps David could comment about the 'mismatch' of membrane surface and hornsegment surface, if that would have any effect on simulations ?

/Erling
Click to expand...

Yes - that would be good to know - to my understanding the "hornless front chamber" of a ripole includes some volume that might make it behave a little bit like a band-pass or like a transmission line - but with kind of "distributed drivers" along the line.
Or possibly seen otherwise - like a tapped horn with no horn afterwards.

I just do not know how Hornresp deals with such things ?

backview2.JPG


Michael


Michael
 
#1,335
skorpion said:
Perhaps David could comment about the 'mismatch' of membrane surface and hornsegment surface, if that would have any effect on simulations?
Click to expand...

Hi Erling and Michael,

For the example you have given, I would think that the Hornresp predictions should be reasonable. Obviously though, as the difference in areas becomes very large, the accuracy of results will decrease. The program assumes that the driver is loaded by the throat acoustical impedances of the cylindrical horns mounted on each side of the diaphragm.

Kind regards,

David
 

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#1,336
mige0 said:
One thing I noticed is that the spectrogram seems to have different SPL scaling than the SPL plot.
Comparing the difference in SPL from 300Hz and 100Hz its about 30-40dB indicated by the spectrogram whereas its at a more realistic 15dB in the SPL plot?
Click to expand...

Hi Michael,

Jean-Michel would perhaps be best placed to comment on this. He is off-line until August 20th.

Kind regards,

David
 
#1,337
David McBean said:
Jean-Michel would perhaps be best placed to comment on this. He is off-line until August 20th.
Click to expand...

Hi Michael,

Jean-Michel may wish to provide more detail - but essentially, as indicated in the Hornresp Help file, the impulse spectrogram displays the normalised amplitude in decibels as a function of frequency, versus time in milliseconds.

The spectrum amplitude is normalised between the limits of 0dB and -40dB.

Kind regards,

David
 
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