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Old 28th January 2012, 04:43 AM   #1451
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Quote:
Originally Posted by Djim View Post
In figure 4, I made a suggestion for a new screen page that shows the "POWER response" with all valuable information. If Zmin is not used this page is not available.

Click the image to open in full size.
Hi Djim,

Just curious - what power is shown in the Figure 4 Power Response chart, and how is it calculated? Thanks.

Kind regards,

David
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Old 28th January 2012, 09:01 AM   #1452
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Quote:
Originally Posted by David McBean View Post
Hi Djim,

Just curious - what power is shown in the Figure 4 Power Response chart, and how is it calculated? Thanks.

Kind regards,

David
The “Flip Horizontal” function calculates that curve quite nicely .
It provides all any sound engineer needs to know, one can put a narrow Q boost at 56 Hz on the kick drum and not burn the voice coil in this cabinet because an amplifier won’t deliver significant power in to a 58 ohm load.

I consider Djim a friend, but this pursuit of his is a 58 ohm load of haufen mist .

Art
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File Type: png Flip,Flop&Fly.png (152.2 KB, 438 views)

Last edited by weltersys; 28th January 2012 at 09:04 AM.
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Old 28th January 2012, 03:53 PM   #1453
Djim is offline Djim  Netherlands
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Hi David,

Figure 4 is like my other examples screens just an example and haven't paid much attention to its accuracy. But figere 4 is based on a Voltage constant of 2.9V (figure 1) at an power of 1 Watt based on the lowest impedance of 8.4409 Ohm in the bandpass at 88.67Hz.

Hi Art,

A model should be theoretically correct and doesn't 'see' reality. In other words in reality the impedance peak would be much lower and wouldn't end in a perfect pointy peak. Even for friends, in theory it would be difficult to burn out the VC at that specific point since it would go way beyond its Xmax much sooner
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Old 29th January 2012, 01:59 AM   #1454
Djim is offline Djim  Netherlands
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I'll show another example of Power in relation to Impedance how it should look like (note: this one is an accurate theoretical model )
Black = Power (in Watts)
Red = Impedance (in Ohms)
Purple = Excursion (in 0.1mm)

Click the image to open in full size.

Last edited by Djim; 29th January 2012 at 02:03 AM.
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Old 29th January 2012, 05:10 AM   #1455
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Quote:
Originally Posted by Djim View Post
Figure 4 is like my other examples screens just an example and haven't paid much attention to its accuracy. But figere 4 is based on a Voltage constant of 2.9V (figure 1) at an power of 1 Watt based on the lowest impedance of 8.4409 Ohm in the bandpass at 88.67Hz.
Hi Djim,

Thanks for clarifying that the Power Response chart shown in Figure 4 is for illustrative purposes only, and that the results are not meant to be an accurate representation of what actually happens in practice.

Just for the record - using your Figure 1 input parameter values, the predicted electrical input power will be as shown in attachment 1, and the predicted acoustical output power will be as shown in attachment 2.

The information used to generate the two attachments was taken from Hornresp exported chart data.

Kind regards,

David
Attached Images
File Type: png Power_In.png (71.5 KB, 359 views)
File Type: png Power_Out.png (68.9 KB, 357 views)
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Last edited by David McBean; 29th January 2012 at 05:13 AM.
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Old 29th January 2012, 05:30 AM   #1456
Djim is offline Djim  Netherlands
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Hi David,

Looks great!
Out of curiosity, since all the data is already there in the export file why haven't you put it in a chart within HornResp before?
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Old 29th January 2012, 07:22 AM   #1457
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Quote:
Originally Posted by Djim View Post
Out of curiosity, since all the data is already there in the export file why haven't you put it in a chart within HornResp before?
Hi Djim,

While the variation of electrical input power with frequency for a constant input voltage is certainly of some interest, I didn't think that it was really necessary to provide the information in a chart in Hornresp. Power values can be readily checked at particular frequencies if required using the Sample tool with the SPL response chart, or by scanning the exported chart data.

Incidentally, it is interesting to note the difference between the power calculated by Hornresp - which takes into account the resistive and reactive components of the complex impedance Ze (red trace), and the power calculated using simply the magnitude of Ze as given in the Hornresp electrical impedance chart (blue trace).

Kind regards,

David
Attached Images
File Type: png Power_Compare.png (74.3 KB, 50 views)
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Last edited by David McBean; 29th January 2012 at 07:31 AM.
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Old 29th January 2012, 07:09 PM   #1458
Djim is offline Djim  Netherlands
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Hi David,

Ooohhh I like these charts very much! The last chart raises the question if the complex calculation method is always similar to the Zmin calculation within the 1/4WL and full WL?

An example of how these charts can be used :-)
Instead of looking to the SPL Response for setting out the bandpass, you can also use the Power chart for a more balanced power bandpass, or to show where the dynamic compression points can be found. Lots of extra information...
I use the 1 Watt horizontal as reference line in both examples (this could also be your max AES power or the power based on Xmax for instance).

Click the image to open in full size.

Last edited by Djim; 29th January 2012 at 07:11 PM.
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Old 30th January 2012, 07:12 AM   #1459
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Quote:
Originally Posted by Djim View Post
The last chart raises the question if the complex calculation method is always similar to the Zmin calculation within the 1/4WL and full WL?
Hi Djim,

Attached are the power curves for the William Cowan 60 hertz tapped horn with Eg = 2.83 volts.

Kind regards,

David
Attached Images
File Type: png TH.png (75.3 KB, 31 views)
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Last edited by David McBean; 30th January 2012 at 07:14 AM.
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Old 30th January 2012, 03:06 PM   #1460
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David,

Have you given any thought towards allowing the ability for complex inductance effects to be included into HR modeling? Many of the modern high power bass drivers on the market cannot be accurately simulated with parameters not including inductance or even using a simple inductance model when that information is actually given.

For example see the attachment. This is a simulation of a driver in a sealed enclosure using the measured specification without LE (Red response curve), using the simple LE model (Orange response curve), which is what capability HR currently has and finally using complex inductance (Yellow response curve).

q18 wt2 simulation.PNG

I have also attached a real measurement of the driver in question in the enclosure to show how closely the complex model matches and how progressively more inaccurate the simpler models are without this information. Note this is not an outlier driver either, this type of response and sensitivity variation due to inductance is very common with large bass drivers. Some are much worse than this.


close mic in room q18.jpg
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