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Old 6th May 2009, 10:13 AM   #501
Jmmlc is offline Jmmlc  France
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Hello David

That's OK, so in the case of the combined response, the artifacts are probably due to the phase wraping.

Unwraping the phase should solve this.

Could you send me the SPL and phase used for the pulse response for the following example :

http://www.diyaudio.com/forums/atta...tamp=1239376483

or for other examples as the ones illustrated by Sabbelbacke...

Best regards from Paris, France

Jean-Michel Le Cléac'h



Quote:
Originally posted by David McBean
Just to clarify, the phase shown on the phase response chart is not the same as the phase used in the impulse response calculations. The phase for the combined response impulse response is recalculated, and hopefully is the phase of the combined outputs.

The phase shown on the chart does not change because as Eva has pointed out, it simply shows the phase shift through the driver only. It is not updated at any time.

Kind regards,

David
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Old 6th May 2009, 10:13 AM   #502
Eva is offline Eva  Spain
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Jmmlc is more or less complaining about the same thing as me. The phase and group delay shown when the combined response option is used are not updated either.

There is currently no way to know combined phase and group delay. A real pity for tapped horns.
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Old 7th May 2009, 05:13 AM   #503
GM is offline GM  United States
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Default Re: Hornresp Version 21.40

Quote:
Originally posted by AndrewT

use dos to swap folder names back and forth.
Have two or three icons, each uses a different dos file to use the folder you need.
Thanks, I was afraid this would be the solution. Fortunately though.........

Quote:
Originally posted by David McBean

Also, the limit on the maximum number of data records has been increased to 9999 - hopefully this will be enough even for GM :-).
Thanks, appreciate it! Actually, now that MJK has withdrawn his MathCad software I've been promoting HR as a basic substitute for MLTLs, etc., so if the 2500+ MC sims are any indication plus all the compound horn sims I plan it might not be if I don't die young .............

Speaking of which, any hope of getting an adjustable vent location option to go along with the offset driver option?

BTW, in playing with the new features, I did a simple sealed cab sim (attached), looked at the various graphs, clicked on FIND expecting to be asked if I wanted to save it and instead got a pop-up "runtime error '9' subscript out of range", clicked OK and it closed HR without saving the sim. So far though, in looking up a few impulse plots of existing sims it hasn't happened again.

GM
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File Type: gif b&c 8ndl51 (dual) 0.5 qtc sealed.gif (14.7 KB, 516 views)
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Old 7th May 2009, 05:24 AM   #504
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Quote:
Originally posted by Jmmlc
Could you send me the SPL and phase used for the pulse response for the following example
Hi Jean-Michel,

I can do even better than that :-). Please see my latest email.

Kind regards,

David
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Old 7th May 2009, 05:34 AM   #505
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Quote:
Originally posted by Eva
There is currently no way to know combined phase and group delay. A real pity for tapped horns.
Hi Eva,

The attached screenprint shows the system phase response for the William Cowan 60 hertz tapped horn with Eighteen Sound 10W400 driver.

The system group delay for the same loudspeaker is given in my next post.

How would you use this information to improve the design?

Kind regards,

David
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File Type: jpg phase.jpg (49.3 KB, 519 views)
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Old 7th May 2009, 05:36 AM   #506
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Quote:
Originally posted by David McBean
The system group delay for the same loudspeaker is given in my next post.
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File Type: jpg delay.jpg (42.8 KB, 513 views)
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Old 7th May 2009, 05:54 AM   #507
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Default Re: Re: Hornresp Version 21.40

Hi GM,

Quote:
Originally posted by GM
I've been promoting HR as a basic substitute for MLTLs, etc., so if the 2500+ MC sims are any indication plus all the compound horn sims I plan it might not be if I don't die young .............
Sorry, 9999 records are all you are going to get :-).


Quote:
Originally posted by GM
Speaking of which, any hope of getting an adjustable vent location option to go along with the offset driver option?
Very little at this stage, I'm afraid :-).


Quote:
Originally posted by GM
BTW, in playing with the new features, I did a simple sealed cab sim (attached), looked at the various graphs, clicked on FIND expecting to be asked if I wanted to save it and instead got a pop-up "runtime error '9' subscript out of range", clicked OK and it closed HR without saving the sim. So far though, in looking up a few impulse plots of existing sims it hasn't happened again.
Many thanks for the feedback. I haven't been able to generate the error myself - hopefully it was a "one-off". Could you please let me know if it happens again. I have checked the relevant code, and as far as I can see everything should be okay.

I have assumed that you are now using Version 21.50.

Kind regards,

David
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Old 7th May 2009, 06:15 AM   #508
GM is offline GM  United States
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Greets!

Correct, will do. Not knowing what it meant, I wondered if it had something to do with me having previously overwritten sim 999, then deleting another one, dropping it to 998 using the older version, then making another 999 in the latest version causing a one time glitch in the database conversion.

GM
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Old 7th May 2009, 06:51 AM   #509
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Quote:
Originally posted by GM
Not knowing what it meant, I wondered if it had something to do with me having previously overwritten sim 999, then deleting another one, dropping it to 998 using the older version, then making another 999 in the latest version causing a one time glitch in the database conversion.
Hi GM,

The 'subscript out of range' runtime error is generated when an array element is given an index number greater than the allowable array size.

I suspect that in your case, the error was generated exactly because of the sequence of events you described.

With any luck, it will not happen again.

Thanks for providing the additional information.

Kind regards,

David
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Old 7th May 2009, 07:54 AM   #510
Eva is offline Eva  Spain
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Quote:
Originally posted by David McBean


Hi Eva,

The attached screenprint shows the system phase response for the William Cowan 60 hertz tapped horn with Eighteen Sound 10W400 driver.

The system group delay for the same loudspeaker is given in my next post.

How would you use this information to improve the design?

Kind regards,

David
The phase plot includes propagation delay, thus making it much harder to interpret due to wrappings, and the scale of the group delay plot is too wide (the negative spikes are a calculation artifact) making quite hard to see the small bumps. I can't see clearly on these plots the information that I would need to try to make this design more crossover-friendly, although it seems to be good already.

When designing a horn it's useful to know in advance where are going to be the bumps in group delay because they require compensation in the crossover for proper summing. Knowing in advance the kind of compensation required is useful. The size of front and rear chambers has a great impact on these bumps too, they may be "shaped".

For example, I'm trying to determine the rear chamber size for my midrange horns that results in the most uniform group delay (or a good compromise between size and the resulting peak) and Hornresp currently does not help me at all because the response after the sound travels through the horn is completely different from shown.

For tapped horns (and scoops) a group delay plot allows to know in advance the irregularities that require compensation on the top octave, so that they can be minimized, moved or the way to compensate them can be known in advance. Measuring this in practice is quite difficult.

For front loaded bass horns, having actual phase and group delay plots allows to evaluate the amount of phase and group delay ripple depending on how much size reduction is applied. This ripple causes bad summing in the crossover region and may need external correction. I usually compensate bottom octave ripple by adjusting the size of the rear chamber, and top octave ripple by adding a last extra section to the horn with an higher cutoff. But again, the current phase and group delay plots tell nothing about whether I'm doing it right or not.
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