Hornresp - Page 312

whgeiger · 22nd January 2013, 12:47 AM

Hi David

For an additional option you may want to consider Cornu's spiral. It is a plane curve whose curvature is proportional to its arc length, and whose Cartesian coordinates are given in parametric form by the Fresnel integrals. Also known as a clothoid; Euler's spiral it is similar in form to JMLC’s method of determining horn wall geometry. I suspect that one may well be a parameterization of the other. For details see: Euler's spiral

Regards,

Bill

David McBean · 22nd January 2013, 05:13 AM

Quote:

Originally Posted by more10

I was trying to change from Lec to Rad, but coultn't.

Hi more10,

To change from Lec to Rad, double-click on the Lec label in edit mode and then press R.

Kind regards,

David

David McBean · 22nd January 2013, 05:22 AM

Quote:

Originally Posted by Kolbrek

Hornresp could include an algorithm to determine your state of alertness, and shut down if you are too tired

Or perhaps it could make you a strong cup of coffee instead :-).

David McBean · 22nd January 2013, 05:39 AM

Quote:

Originally Posted by David_Web

Can F45 label be used to show mouth angle?

Hi David_Web,

The radius horn mouth flare tangent angle is given by the Fta parameter.

The Horn Segment Wizard enables Fta to be specified as an input value if so desired.

Kind regards,

David

David McBean · 22nd January 2013, 05:49 AM

Quote:

Originally Posted by David_Web

The design tool for Rad has a bug in it allowing it to calculate invalid horn with negative volume.

Hi David_Web,

Many thanks for bringing this to my attention - it will be fixed in the next release.

Kind regards,

David

David McBean · 22nd January 2013, 06:06 AM

Quote:

Originally Posted by whgeiger

For an additional option you may want to consider Cornu's spiral.

Hi Bill,

Thanks for the suggestion - I suspect that it might be a little too esoteric for Hornresp though :-).

Kind regards,

David

Don Hills · 22nd January 2013, 08:12 PM

Quote:

Originally Posted by whgeiger

... For an additional option you may want to consider Cornu's spiral. ...

Bill,
It is very close to an exponential profile. See here:
Ever think of building a Cornu Spiral horn? Now you can!

David McBean · 23rd January 2013, 05:51 AM

Hi Everyone,

1. Schematic diagram horn profiles are now perfectly symmetrical for all screen resolutions and text size settings. Previously, one-pixel-width "quantisation error" discrepancies could sometimes be seen. The change is purely cosmetic, and the calculated results are not affected in any way.

The attached screenprints show an example of the "old" and "new" profiles. Note the subtle differences - particularly near the throat.

2. The radius horn segment wizard bug reported by David_Web has been fixed.

Kind regards,

David

David McBean · 24th January 2013, 05:34 AM

Hi Everyone,

A small spurious spike present at high frequencies in the throat acoustical impedance chart results for some radius horns, has now been eliminated.

See old / new comparison screenprints attached.

Kind regards,

David

AndrewT · 24th January 2013, 09:51 AM

David and others,
could you talk us through what the "shape" of those plots is telling us?
There are some small ripples on the flanks, what do they mean?
There is an asymetry over the peak, what does that mean?
Why does the black have a more pronounced ripple at ~900Hz
What is the difference in the red and the black?
Why the difference in slopes before and after the peak? Red is slow before and fast above, whereas black is fast below and slow above?
Why is the red at zero at both limits whereas the black is zero at low limit and 1 at the high limit? Is it exactly 1? Why 1, what does that mean?

22nd January 2013, 12:47 AM	#3111
whgeiger diyAudio Member Join Date: May 2004 Location: Pensacola, Florida	Yet Another Alternative Horn Curve Hi David For an additional option you may want to consider Cornu's spiral. It is a plane curve whose curvature is proportional to its arc length, and whose Cartesian coordinates are given in parametric form by the Fresnel integrals. Also known as a clothoid; Euler's spiral it is similar in form to JMLC’s method of determining horn wall geometry. I suspect that one may well be a parameterization of the other. For details see: Euler's spiral Regards, Bill

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24th January 2013, 09:51 AM	#3120
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	David and others, could you talk us through what the "shape" of those plots is telling us? There are some small ripples on the flanks, what do they mean? There is an asymetry over the peak, what does that mean? Why does the black have a more pronounced ripple at ~900Hz What is the difference in the red and the black? Why the difference in slopes before and after the peak? Red is slow before and fast above, whereas black is fast below and slow above? Why is the red at zero at both limits whereas the black is zero at low limit and 1 at the high limit? Is it exactly 1? Why 1, what does that mean?