# Dayton EEM-6. Have cal chart chart but have questions.



## fastline (May 7, 2010)

I have uploaded the chart. I do not quite understand the "correction factors" and how this might relate to my setup of software. I want to ensure that the dbs showing in the software reflect accurate measurements. 

Also, it looks like the test was performed at -40.3db, shall I use this as "flat" and any deviance from 40.3 would be an correction factor in a calibration file?


ALso, I have been trying to get a hold of Dayton all day to ask about these questions. No one answers the phone and no one returns a call. Is this typical of them? I thought they were a pretty good company?? This chart I have IMO is hard to see "exactly" what the values will be. I was hoping for a list of values that I could just enter into a cal file. Looks like I will have to guess as to what the values should be....

Another, I see where there are adjustments are made in a cal file but wondering if there is a "Q factor" applied to a curve that is used when applying a correction factor? IE, if I correct 50hz at -2db, how will 52hz react??


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## fastline (May 7, 2010)

To better understand, I would like it spelled out I guess. IE, in the graph, when the curve goes, lets say up 2db, I would add a correction factor for ""-2db"" in the software? I am just trying to understand this graph and how it is derived.


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## Wayne A. Pflughaupt (Apr 13, 2006)

It’s not clear from your post what it is you’re trying accomplish. Are you trying to create a calibration file from the attached graph to use with REW? If so you might want to review this post on how to create a calibration file.




> Also, it looks like the test was performed at -40.3db, shall I use this as "flat" and any deviance from 40.3 would be an correction factor in a calibration file?


Yes.




> Another, I see where there are adjustments are made in a cal file but wondering if there is a "Q factor" applied to a curve that is used when applying a correction factor? IE, if I correct 50hz at -2db, how will 52hz react??


There is no Q factor. How 52 Hz will react depends on the calibration values beyond it. For instance, if you have a calibration value at 50 Hz of – 2 dB, and the next value is -6 dB at 55 Hz, then 52 Hz will be somewhere between – 2 and -6 dB.

Regards,
Wayne


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## fastline (May 7, 2010)

So in other words, REW will plot straight lines?


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## Wayne A. Pflughaupt (Apr 13, 2006)

REW will plot straight lines between the data entry points of the calibration file, if that’s what you’re asking.

Regards,
Wayne


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## fastline (May 7, 2010)

Wayne, after looking at your graph and values, it looks like you are doing the opposite of what I imagined. 

For instance, at 5500hz, your graph goes up to +5db, so you put +5db in your table. I honestly figured that to mean the mic responded with higher dbs so the correction factor would be the opposite so -5db. Can you clarify?


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## fastline (May 7, 2010)

Wayne A. Pflughaupt said:


> REW will plot straight lines between the data entry points of the calibration file, if that’s what you’re asking.
> 
> Regards,
> Wayne




Yes. To add to that, do you have to add a function to return it back to flat or 0? IE, 500hz needs +2db but 600 needs 0, if I create a line in the cal file for 500 +2, will REW stay at +2 until giving another command such as 600 0 to bring it back to flat? 

Probably some dumb questions but we program CNC machines all day and they are rather stupid so they usually require on and off commands for about everything....




Also, regarding construction of the .cal file, I have seen other software such as "db plot" that will plot the graph and kick out the values which is probably a bit more accurate than just looking at the graph. However, I cannot seem to get the software to work right. Not finding my jpg file for some reason.


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## Wayne A. Pflughaupt (Apr 13, 2006)

The calibration file tells REW what the actual response of the mic is. When REW “sees” +5 dB at 5500 Hz, for instance, the program will subtract 5 dB at that frequency. Make sense?

Regards,
Wayne


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## Wayne A. Pflughaupt (Apr 13, 2006)

> To add to that, do you have to add a function to return it back to flat or 0? IE, 500hz needs +2db but 600 needs 0, if I create a line in the cal file for 500 +2, will REW stay at +2 until giving another command such as 600 0 to bring it back to flat?


As mentioned:



Wayne A. Pflughaupt said:


> REW will plot straight lines between the data entry points of the calibration file...


 IOW, If you want the correction to remain flat above 500 Hz to 600 Hz, you’ll have to “tell” it that:

500 +2
599.999 +2
600 0

I.e., the corrected response is going to trace whatever calibration entries you include, plain and simple.

Regards,
Wayne


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