Edit directivity

Directivity measurements in one or two planes are to be displayed and edited here. Two sections are available for the horizontal and vertical measurements, which are to be edited independently.

X-axis and y-axis represent frequency and angle respectively. Level is illustrated by colours. If Normalize is active, directivity is displayed relative to a main axis (usually the 0° hor, 0° ver direction). The colours then visualise the decrease of sound pressure compared to the main axis.

Measurement info

Manufacturer, Loudspeaker type and Configuration information can typed into the corresponding fields. These are displayed in the header of the diagram in this order.

Reload and refresh

Reload data & refresh reloads the directivity data and refreshes the display, Refresh only updates the display with the selected parameters.


The Import of measurements is performed either from a directory containing single measurements from WinMF or Monkey Forest (Hor/Ver from SPK folder), or by a POX file (Hor/Ver from POX file). POX is an ASCII format used by Monkey Forest. The measurements are assigned to the Hor and Ver domains correspondingly.

SPK balloon to directivity: Inside a directory containing a balloon measurement in the form of single SPK files, this function creates two subdirectories hor and ver, where the measurements in the horizontal and vertical planes from the balloon measurement are put into. If the balloon measurement only contains a half or quarter balloon due to symmetry, the files missing for the directivity data set are created by mirroring and put inside the subdirectories.


Save hor./ver. dir. as VACS ASCII saves the content of the hor./ver. field in the format of VACS, a visualising tool which can display various audio measuring formats.


Default configurations for plotting the directivity can be loaded: +/-90° 1/12 oct. smooth and +/-180° 1/3 oct. smooth. These settings can further be edited.


Show horizontal/vertical controls switches visibility of the Horizontal/Vertical setup menus containing parameters for plotting the directivity.

Horizontal/Vertical setup

The first data field contains the data path as selected when importing the data. It can be edited manually.

Import step [°]

The angle grading of the single measurements to be imported is entered here.

Azimuth [°]

If the spk directory contains several planes or a balloon measurement, Azimuth [°] defines the plane to be displayed as directivity. 0° and 90° specify the horizontal and the vertical plane respectively. With balloons it is possible to select planes in between.

Upper/Lower limit [Hz]

These parameters define the upper and lower limit of the frequency range to be displayed.

Max./Min. Angle [°]

This defines the angle range to be shown.

Lev. max./min. [dB]

These parameters define the level range to be represented by the colour spectrum. The colour grading is spread evenly across the level range specified here. When using the standard values +3dB/-30dB, the colour transition from orange to yellow represents the -6dB contour line, which is commonly used as definition for dispersion width.

Ref. method

Plotting of relative levels (Normalize activated) is done in relation to a designated single measurement or an average of several single measurements.

Choosing sel. axis allows selecting the reference measurement under Ref. axis 1. Standard setting is reference to 0°.

av. both. axes allows referring to the Average of two single measurements, which are to be specified under Ref. axis 1 and Ref. axis 2.

av. between axes takes the average of the range from Ref. axis 1 to Ref. axis 2 as reference.

Cyc. mov. [step] performs a cyclic move of the single measurements. The value to be specified here is the number of steps to be taken, considering the angle written under Import step [°].

Show 0° impulse response

This function performs an IFFT of the 0° measurement and plots the result in the time domain window.


Mirror: The directivity from the positive angle range is mirrored to the negative range.


All single measurements are processed as described in Processing. Notably windowing and smoothing can be applied to the single measurements. The setup for this is done via Proc. para.