Charting Sub Responce in Excel (1 Viewer)

[Mark Fitzsimmons]

I have to do a project in Excel for my computer programming class. So I charted the responce of my sub at 1/6th octave incriments, I then graphed those results. Now, I want to apply the correction values and graph it again. I took my best shot at it but it didn't come out right. Can someone tell me how to apply the correction values in an Excel database?
Heres what I have so far...
www.markfitzsimmons.com/htforum/
Thanks

 

[Anthony_Gomez]

Mark, first of all, you need your correction values to apply to ALL frequencies. If you download my spread sheet, it has corrections extrapolated out to 1/12th octaves.
The second problem is that your frequencies need to continually increase. ex: 20,21.1,22.4,23.7 and NOT 21.1,22.4,20,23.7 (this happens more than once)

 

[Mark Fitzsimmons]

I don't know why it wasn't in order, I know when I typed them in, they were in order. I guess I hit a button or something by accident that moved them out of order.

OK, well I went back and put them in order. Since I'd like it to be my work for this project, can you tell me how to extrapolate out the correction values and apply that to my spreadsheet?

 

[Patrick Sun]

Maybe I'm missing something, but all I did was create:

1st column: Frequency (Hz)
2nd column: SPL measured for given frequency (db)
3rd column: 2nd column cell +/- correction factor. (this is the column with the corrected SPL level for a given frequency.

To plot the graph, just use the 1st column as the frequecy (X-axis), and the 2nd and 3rd columns for the data (SPL) for the measured and corrected SPL values (Y-axis)

 

[Anthony_Gomez]

Pat, you didn't miss anything. THat is what you should do. you should actually create 4 colums though (for ease of use)
1=frequency
2=raw spl
3=correction
4=corrected spl

 

[Patrick Sun]

You get school credit for this sort of stuff? I feel old...

 

[Anthony_Gomez]

see...I need to find a way to convince the purchasing department that I HAVE to buy all sorts of quality audio gear/speakers so that I can accurately test chemical reactions pertibated by sound waves
..ya...um...I will be proving that ...ummm...the "sound waves" from quality music/movie recordings inhibit the production of tropospheric ozone

 

[Mark Fitzsimmons]

I corrected it from Anthony's instructions. Check it out now.
Thanks for the help

 

[Anthony_Gomez]

looking better.

use a log scale on the x-axis, and have the spl go from 80-120db on both graphs

 

[Mark Fitzsimmons]

Definitly looks better on 80-120, but I can't figure out how to get the log scale to work correctly... lil'help?

 

[Pete Mazz]

If you go into "Format Axis" and select "Properties" then "Scale", click on logarithmic and you'll have to set your max value to 100.

Pete

 

[Mark Fitzsimmons]

OK, I had that before, but didnt think it was useful, since there are no numbers inbetween 10 and 100 on my graph when I put it on logarithmic; making it harder to interpret.

What are the advantages to a logarithmic scale?

 

[Mark Fitzsimmons]

Any suggestions on how I can make this better?

 

[Dan M~]

Reviving this old thread to ask:

Anthony_Gomez-

If you download my spread sheet, it has corrections extrapolated out to 1/12th octaves.

I don't see a spread sheet on your site. I downloaded the tones, but failed to find the corrections for the RS SPL meter. Help... :b

 

[Anthony_Gomez]

dowload the PEQ program. It is an excel based spread sheet that is intended for use with the BFD. On the measurements page (where you type in data), it has the corrections. (extrapolated from 1/3 octave)

 

[Dan M~]

Got it, Thanks.