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iOS app for measuring sound directivity of loudspeakers and microphones
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Polar Pattern Plotter

Polar Pattern Plotter is an iOS app for measuring sound directivy patterns for loudspeakers and microphones. The iOS binary is available for free download on the App Store:

Source code is provided here for those who'd like to help improve the functionality of the app for the good of the community. See below for suggested improvements!

PPP Web Site

Paper: "Visualizing Sound Directivity via Smartphone Sensors," by S.H. Hawley and R.E. McClain Jr., The Physics Teacher 56, 72 (2018). Also pre-print on


  • Make sure you have Xcode installed.
  • Clone this GitHub repository.
  • Open the .xcworkspace file with Xcode, e.g. $ open PolarPatternPlotter.xcworkspace
  • Choose "Run" from the "Build" dropdown, or just click the "Play" (▶️) button.


Features to be added (you can help!):

  • A variable frequency-filter, to reject background noise and to allow simultaneous experiments (at different frequencies).
  • Corrections to angular drift. Currently there's a slider but it's not enabled. The code for this isn't quite working and it's commented-out in the source.
  • Interpolate / smooth the data, and do polar-harmonic decomposition
  • Port it to Android
  • Some kind of "burst mode," where the phone outputs the test signal and rejects sounds that arrive after some (tunable) interval, to allow for use in reflective rooms.

Author: Scott Hawley

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