Weighting Curve Files

Macros: CurveFile0-3, Curve0LI, RI, LO, RO, etc

There are four separate buttons for loading Curve files. Below each Curve button is a row of four smaller channel select buttons. These are disabled until a file is loaded.

Channel buttons are interlocked vertically, so you may apply only one Curve to any given channel, but any number of channels may use the same Curve.

Curve files have a .CRV extension but use the same format as Calibration .CAL files. A Curve file must have a 'Unit:' name and a 'Sens:' value, but those entries will be ignored. Following must be a list of up to 512 lines, each line with a frequency value in Hertz, then one or more spaces, then a dB value for the relative response at that frequency.

Here is a simple Curve file example:

    Unit:None
    Sens:0
    0       -90
    10      -20
    100       0
    500       6
    1000      0
    5000    -20
    50000   -90

This example file will boost the value at 500 Hz by 6 dB. Frequencies between 100 and 1000 will be boosted using simple linear interpolation within each defined curve segment. For example, in the segment between 100 and 500 Hz, 300 Hz is half-way and would be boosted 3 dB (half of 6 dB).

The first line should be for 0 Hz; if one is not found, a default entry of -90 dB will be assigned.

The last line should be at least as high as the highest frequency of interest. Responses for higher frequencies will be found by extrapolation, which tends to give poorer results than interpolation here.

Several Standard weighting curves are supplied with Daqarta, especially for use with the Sound Level Meter option.

Loaded Curve files and channel selections will be retained for future Daqarta sessions.

If you want to remove a specific Curve, click on it and you will see a confirmation prompt. If you accept, that Curve will be unloaded and you will be able to load another to that button.

Macro Notes:

CurveFile0 to CurveFile3 macros have no effect if any File Open or Save As dialog is already active.

CurveFile0= without a name will pop up the File Open dialog for Curve 0, showing all CRV files but with no default name.

CurveFile0="MyCurve" will pop up the File Open dialog with the default name set to MyCurve. (Note that quotes are needed around all filenames in macros.) If you accept this by hitting Enter or the Open button in that dialog, Daqarta will attempt to load a file named MyCurve.CRV as Curve 0, and will fail if that file is not found.

A.CurveFile0="MyCurve" will load MyCurve.CRV directly to Curve 0, without any File Open dialog. Note that if there was a file already loaded for Curve 0, it will be replaced with the specified file.

CurveFile0=">Field1" will use the contents of Field1 as the default file name, and A.CurveFile0=">Field1" will load a file of that name directly.

Once a Curve 0 file has been loaded, you can select it for use on a given channel via Curve0LI=1 for Left Input, Curve0RI=1 for Right Input, Curve0LO=1 for Left Output, and/or Curve0RO=1 for Right Output. If you use a value of 0 instead of 1, the specified channel will be unselected for that curve. A value of x will toggle the specified channel from its current state.

You may load curve files to any Curve button; they do not need to be loaded in any order.

If a Curve button already has a file loaded, you can unload it by giving another CurveFile command. CurveFile0= (with no name given) will prompt you to confirm unloading Curve 0. If you use A.CurveFile0= the current file will be unloaded without any confirmation prompt.

To test if a Curve button already has a file loaded, you can use an IF statement with a 0 or 1 in place of the file name. IF.CurveFile0=1 will be true if there is a file loaded.

See also Spectrum Curves Dialog, Mirror Curve Files, Spectrum Control Dialog