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. 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. See this tutorial topic for more information.
Such a text file is said to be in FRD format, even if its extension is something other than .frd. 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.
Before You Export Text: Guaranteeing That Smoothing Will Be Removed
In REW, there is a condition related to the Allow 96 PPO log spacing option that can prevent all smoothing from being removed. To guarantee that all smoothing will be removed in the export steps described below, it's important to first check the Allow 96 PPO log spacing option in the Analysis tab of the REW Preferences dialog. If that option is enabled, or if it was enabled at the time the measurement was performed, or at the time the impulse response measurement window was last applied to the measurement, REW's Remove smoothing command won't remove all the smoothing, but will leave the measurement at 1/48 octave smoothing.
To completely clear out any smoothing effect caused by the Allow 96 PPO log spacing option, perform the following steps:
- In REW, uncheck the Allow 96 PPO log spacing option in the Analysis tab of the Preferences dialog.
- Select any sub measurement.
- Click the IR Windows button.
- Click the Apply Windows To All, Keep Ref Time button in the IR Windows dialog.
Then, when you choose the option to export text without smoothing using the export dialog discussed below, all smoothing will be guaranteed to be removed.
REW's Measurement Export Dialog
There are two ways to export a measurement as text 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.
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. To ensure the exported measurements use no smoothing, choose Use custom smoothing and specify No smoothing as shown in the image above. Next, choose Use REW export format. The Use a separate file for each measurement option should be selected. For the File extension option, choose .txt. For the Export units, choose SPL. For the Export text delimiter, choose Space or Tab. Then click OK to save the files. Choosing the options specified above will ensure all your exported text files are compatible with MSO.
If you chose to export all measurements at once, 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 "POS1-SUB1.txt", "POS2-SUB1.txt", "POS1-SUB2.txt" and "POS2-SUB2.txt".
If you put the name of the position first in the measurement name (which becomes the file name), this makes it easier to use the Measurement Associations page of the MSO Configuration Wizard. See the REW Export section of the tutorial and the tutorial description of associating measurements for more information about why good measurement naming practices make using the Configuration Wizard easier.
Keeping Track of Measurements and Filter Channels
It's a good idea to either keep a rough sketch showing the correspondence of sub name (Sub 1, Sub 2 etc.) to the physical location of each sub, or to name the sub according to its location (e.g. LF, RF, LR and RR). Likewise, these notes should identify the DSP channel that each sub is connected to. If you are using a miniDSP device, it helps to use its channel labeling feature to make each channel's name the same as the name of the sub to which it is connected. 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.