Making a calibration file from a printed analysis

[Synchro]

My t.bone MM-1 mic was supplied with a printed frequency response graph:

I have successfully turned it into a .csv file using Engauge Digitiser, however, I'm not sure that it's in the right format. The points were entered by hand (not placed on 1/12th octave points or anything) and values seem reasonable, however, they are are offset by a sensitivity value of about -47dB, as the graph was presented. Example points:

29.9651,-47.3598
31.7527,-46.69
33.2158,-46.1276
34.012,-46.0726
35.595,-46.6812
36.6064,-46.6791

What do I need to do to this data to turn it into something that software like REW expects?

 

[dengland]

From the Help file

Calibration File Format

The calibration file is a plain text file which by default has the extension .cal, though other extensions are also accepted. It should contain the actual gain (and optionally phase) response of the meter or microphone at the frequencies given, these will then be subtracted from subsequent measurements. The values in the calibration file can be separated by spaces, tabs or commas. Typically the values are relative to the level at some reference frequency, e.g. 1kHz, so the gain value there is 0.0.

• Each line of calibration data must have a frequency value and a gain value, a phase value is optional
• Frequency is in Hz, gain in dB, phase in degrees
• The cal points can be at arbitrary frequency spacing, but each line must have a higher frequency than the one before and there must be at least 2 freq, gain data pairs
• Only lines which begin with a number are loaded, others are ignored
• In comma-delimited files there must be at least one space after the comma
• Spaces before values are ignored

Here is an example section of a valid file format:

SPL Meter Calibration data

20 -15.38
50 -3.69
100 -1.34
200 -0.62
500 -0.26
1000 0.0
2000 1.80
5000 3.95
10000 -0.71
20000 -6.28

I have attached mine for reference.

 

[Synchro]

I'd seen that format, but this is the critical bit:

Typically the values are relative to the level at some reference frequency, e.g. 1kHz, so the gain value there is 0.0.

In my case the graph mentions a 1kHz sensitivity of -46.5dB, so I gather I should offset all my values by that amount?

 

[dengland]

It is an offset that is applied to the measured range. It shouldn't matter.

So, I would just add 46.5dB to each value. That will give you RELATIVE offsets.