You may be wondering how to create the wonderful polar plots of loudspeaker response that you've seen online. In this app note we will show you step by step.
Requirements [Top]
-
Room EQ Wizard (REW) from https://www.roomeqwizard.com
-
VituixCAD from https://kimmosaunisto.net
Step by step [Top]
-
Create measurements at different degrees in REW, either free field measurements or with the near field/far field merger technique. Name the files accordingly to the position.
-
Bulk export the measurements as .txt files.
-
Start VituixCAD and connect the amplifier source to the loudspeaker via a virtual wire.
-
(1) Go to Options and use the CTA-2034-A preset. (2) Test if your naming pattern used for the measurements is interpreted correctly.
-
Start the Merger tool
-
(1) Select Far field measurements>. (2) Load your measurement .txt files. (3) Save the new measurement set. (4) Make sure to select Feed speaker. (5) Click on Save.
-
The preview window in VituixCAD will now show your SPL on top, Spinorama in the middle window and isobaric plots in the bottom left window. Polar plots and settings can be accessed via right click into the window. The isobaric plots give you a quasi‑3D display of level, frequency and degree at the same time. In the 2D polar plot, the directivity per frequency can be evaluated.
Wrapping up [Top]
That's it for this app note! Have fun, and please share your experiences in our community forum.
