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Old 24th January 2010, 05:22 PM   #101
gfiandy is offline gfiandy  United Kingdom
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Hi Earl,

I think your spec may have exceeded my excel skills. Excel can almost certainly do it but I am just a casual excel user.

I was going to look at it but I can't even work out how to get the data you described out of Holm inpuse. The only complete datasets I can get are the impulse responses. How do you get a set of frequency data without exporting each one seperately?

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Andrew
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Old 24th January 2010, 05:36 PM   #102
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Doesn't excel have complete VB support. I would think you could write an excel VB script/macro that would import the data from a Holm Impulse file, do the calcs for setting the ranges and any other data manipulation you wanted and then display the graph all in one step.
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Old 24th January 2010, 05:56 PM   #103
gfiandy is offline gfiandy  United Kingdom
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Hi,

Not sure who the last post is directed at, perhaps Earl could do this but I am not a programmer and don't know VB. Like I said I think this has probably exceeded my abilities at this point.

Regards,
Andrew
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Old 24th January 2010, 06:45 PM   #104
gedlee is offline gedlee  United States
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Quote:
Originally Posted by gfiandy View Post
Hi Earl,

I think your spec may have exceeded my excel skills. Excel can almost certainly do it but I am just a casual excel user.

I was going to look at it but I can't even work out how to get the data you described out of Holm inpuse. The only complete datasets I can get are the impulse responses. How do you get a set of frequency data without exporting each one seperately?

Regards,
Andrew
Well to be honest, I don't and maybe thats why this can't work. Ask said that he would setup HolmImulse to output a frequency array, but perhaps he just hasn't done that yet.

I read the impulse responses into MathCad, then add in the nearfield measurement for the low end, smooth to 1/10 or 1/6 octave while I output log spaced points. The smoothing then just becomes part of the interpolation. It may well be that this later aspect is too much to ask Ask to do and it may be quite tough in Excel (i'm not an Excel user either, I don't really like it all that much except for data analysis from subjective tests).

Best bet might be the VB program, but that will take some time.

I just got Visual Studio 2008 and wanted something to try it out on.
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Old 24th January 2010, 07:14 PM   #105
gfiandy is offline gfiandy  United Kingdom
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I think I will gracefully bow out at this point as I know I can't solve that problem. If anyone wants the raw excel file to have a play with; warts and all, let me know.

However I did also want to say, thankyou to Earl for his very illuminating paper. I had struggled with the concept of constant directivity speakers as it seemed that this was a description of an impossible design and I must be missing something. Your paper made it very clear that CD does not in fact mean Constant directivity in this case and controlled directivity is a much better term.

Whilst I think I find the 3D contour maps easier to read, I do now understand your plots. I would recomend changing the plots on your site to be symetircal like the ones in your papers, if you can find time, as this was part of what helped me to visualise better what was going on.


Regards,
Andrew
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Old 24th January 2010, 08:51 PM   #106
SunRa is offline SunRa  Romania
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Hello Andrew,

Please post the excel here. In a week or so I'll be able to look close at it and maybe I'll find a way to easily import the data.

If not, I have a colleague at work, excel wizard, and he is doing just that. Finding ways to get txt. data imported to excel.

I think this would be a usefull piece of data vizualisation...
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Old 24th January 2010, 09:04 PM   #107
gedlee is offline gedlee  United States
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Quote:
Originally Posted by gfiandy View Post
I think I will gracefully bow out at this point as I know I can't solve that problem. If anyone wants the raw excel file to have a play with; warts and all, let me know.

However I did also want to say, thankyou to Earl for his very illuminating paper. I had struggled with the concept of constant directivity speakers as it seemed that this was a description of an impossible design and I must be missing something. Your paper made it very clear that CD does not in fact mean Constant directivity in this case and controlled directivity is a much better term.

Whilst I think I find the 3D contour maps easier to read, I do now understand your plots. I would recomend changing the plots on your site to be symetircal like the ones in your papers, if you can find time, as this was part of what helped me to visualise better what was going on.


Regards,
Andrew
I would like the data, can you PM me with it.

Yes, Controlled Directivity may be a better term, but its also very easy to say that anything is "controlled directivity", so in that sense it doesn't mean very much.

Yes, I agree that the symmetrical plots make more sense. But it is redundent data, so thats why I left it off. Its easy to just fold it over and make a full 180 degree plot so I will do that, thanks.
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Old 24th January 2010, 10:58 PM   #108
gfiandy is offline gfiandy  United Kingdom
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Hi,

I have attached the excel spread sheet. It just fits the upload limit zipped.

This is a rough working sheet so its not documented well.

The CODA III data I had was only at 12.5deg steps so I averaged it to create more steps. It was also a very rough measurement as the reason I was measuring them is the base drivers are failing (the voice coil former is unwrapping - quite common with this speaker) and I was looking at them to try to find a replacement that might work with minimal modification to the crossover. (which I couldn't find, so the garage will be short of speakers for a while longer)

The graphs are on the later sheets so do look at all of them.

The last sheet has some initial prototype work on a linear interpolation algorithm and linear data set. It works to extract log steps from linear data. However the log step sizes need to be sorted to creat a larger set of data.

I did say it was warts and all and there are plenty of warts

Share and enjoy.

Regards,
Andrew
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Old 24th January 2010, 11:20 PM   #109
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There are VB addins to Excel to make contour plots too. See Contour Plotting in Excel for example. It took me about 10 minutes to figure out how to use this.
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Last edited by john k...; 24th January 2010 at 11:23 PM.
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Old 25th January 2010, 12:11 AM   #110
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There may be a very simple low tech solution to the data format dillemma......

I'm not an Exel expert, neither have I played with Holmimpuls yet, but a fairly standard delimited ASCII format would look something like this:

Frequency,Angle1,Angle2,Angle3, etc. etc.
1000,91,95,94, etc.etc.

Once your measurement software can spit out this format, either tab or comma delimited, for instance, you can simply import that into a blank worksheet, let Exel create the columns, then simply copy the columns, and paste them in the corresponding columns of the graphing worksheet.

One can even do any normalizing/massaging of the data in the 1st blank worksheet to make it conform to whatever the graphing worksheet will need, before copying and pasting.

This format seems to be universal, in that my Audio Precision software, and LinearX Leap 5 & LMS 4 will generate data in this format, easy for data exchange between the two, as well as for importing into Exel for whatever analysis/manipulation I may need to do.

Lukas
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