Exporting Measurements From Your Measurement Software
Measurements must be exported in a text format for which the measurement data consists of three columns, separated by spaces or tabs, but not commas. Each row of data must contain frequency in Hz, SPL in dB, and phase in degrees in that order. It's helpful if your measurement software allows exporting user comments to the file. The names of your exported files should contain information allowing the speaker or sub being measured and the listening position at which the measurement was taken to be identified.
Such a text file is said to be in FRD format. In addition to specifying which columns contain which data, this format specifies that optional comments must begin with the "*" character in the first position of each row of comment text. The comment lines must be at the beginning of the file, before the columns of data. MSO accepts this format, but does not require strict conformance to it. The following guidelines apply.
- Any line of text that MSO determines to not be data is treated as a comment and ignored.
- The leading "*" character required of comment lines in the FRD format is not strictly necessary to import them into MSO successfully.
- Lines of text containing frequency response data can use the "dot" character or the comma for the decimal separator, as long as all lines of data are consistent in this regard.
- MSO allows the use of the comma as a decimal separator to accommodate older versions of Room EQ Wizard and other software that uses the operating system's specified locale to determine the decimal separator when exporting measurements as text.
- For this reason, commas must not be used to separate columns of data (as in a .csv file). Do not use the .csv format to export your measurement data.
REW's Measurement Export Dialog
There are two ways to export a measurement in FRD format in REW. To export a single measurement, select the measurement in the tabs on the left of the REW window and choose File, Export, Export measurement as text. This allows you to choose a file name and extension for each measurement text file, but it's tedious because you must do this once for each measurement. The recommended method is to export text files of all of your measurements at once. To do this, choose File, Export, Export all measurements as text. In either case, the following dialog box will appear.
Before continuing, check the status of Use smoothing of measurement:. If it does not say None, you should dismiss this dialog and remove smoothing from all measurements using the procedure in the measurements section.
If the highest measurement frequency is 400 Hz or less, choose Use range of measurement. Otherwise, choose Use custom range, specifying a maximum frequency of 400 Hz. Next, choose Use resolution of measurement. Choose Use smoothing of measurement, which should now say None if you've performed the procedure to remove smoothing. Next, choose Use REW export number format. For the Choose export text delimiter option, choose Space or Tab. Then click OK and save the file(s). Choosing the options specified above will ensure an FRD-compatible export file.
If you chose to export all measurements at once, the file names will be given a ".txt" extension, and the names of the files will correspond to the measurement titles on the measurement tabs at the left of the REW main window. For instance, if the measurement tabs look like the picture below, the exported file names will be "SUB1_MLP.txt", "SUB2_MLP.txt", "SUB3_MLP.txt" and "SUB4_MLP.txt".
Keeping Track of Measurements and Filter Channels
It's a good idea to keep a rough sketch showing the correspondence of sub name (Sub 1, Sub 2 etc.) to the physical location of each sub. Likewise, these notes should identify the DSP channel that each sub is connected to. This will help prevent the data from becoming mixed up when you import them into MSO and name the MSO filter channels. If such a mix-up occurs, the final measured data with all subs activated at once won't match MSO's prediction, and you'll need to do all the measurements over again.