Three phyphoxphones and superposition

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Hi Erik,

I realized some measurements of the classical interference of (sound) waves from two "point" sources (headphones) from a smartphone using "Tone generator" of phyphox. In order to have a stronger sound I have added a small HiFi headphone amplifier as you can see on the given photo.  The result of the interference measurements by a second smartphone with "Audio amplitude" of phyphox is not so bad. It could be better but somebody from a nearby laboratory was not too much happy hearing (reasonably) amplified 4000 Hz. For comparison I have calculated the expected interference pattern for exactly the same parameters:

• Speed of sound Cair = 344 m/s
  
• Frequency f = 4000 Hz
  
• Wavelength (from previous two) = 8.6 cm
  
• Distance between sources L = 54 cm
  
• Distance from the sources to the measurement line d = 69.5 cm
  
• Interval of measurements (second phone scan) x from -50 cm to + 50 cm
  

Knowing the time interval of measurements (with constant speed of the phone) one can recalculate time to x.
Additionally a small modification of the "Audio amplitude" was done to see the sound intensity in the direct scale (also attached here). Unfortunately, I had to keep only French and German translations because somewhere in many others an error existed and I could not find it.

Enjoy
Mikhail