Measurement of the resonance curve (Acoustics)

[fbouquet]

Ah, this is exactly the experiment I wanted to program! Thank you to both of you, Julien, Solid.

I played a bit with the phyphox program.

Concerning the "scratches" when the frequency jumps, I tried many things, but could not avoid them. So I guess we are stuck with it.

Concerning the offset between the measurement and the frequency, I think the reason is that you do not save the data at the right time in your analysis cylce: if I understand correctly, the audio_input that is used was filled with sound from the frequency of the previous analysis cycle, so you should couple the frequency of the previous cycle (before you calculate the new currentF) with the measure of the audio amplitude of the current analysis cycle.

I hope I am clear (and I hope I did not say anything wrong). Here is my implementation of the code I suggest (I also changed the way the frequency is sweep for personal taste).

Now let us look for things to measure... Have you tried a mug?

Cheers,

Fred

[fbouquet]

I played a bit with the phyphox program.

 
I was told that the above program only works for android smartphones, sorry... The reason is hidden in the exact process of opening an experiment which is slightly different on both platform. Here is a version that should work on both, even if I am not totally pleased with the way it is done. Any comment is welcome.

Cheers,

Fred

[solid]

Julien,
your good coincidence here is only by chance (see my answer in 'corkscrew and speed of sound'  in this forum). Here I compare the results of two techniques for a different graduated cylinder (100 mL):

           

The resonance frequency for the direct measurements was obtained by fitting the resonance curve, which is pretty good in this case.

[julien]

well done !

[solid]

The results with somewhat corrected "corkscrew and speed of sound"  program.

       

[Sebastian Staacks]

Little update:
I just submitted a beta version for the next phyphox update 1.1.6 (well, it is more alpha than beta as there are not even all features for this version included), which includes a new tone generator module. This is not (yet) supported by the editor, but if you are comfortable with directly editing XML, you can try to use this module for synchronization.

With the new audio output module, you can define the tone parametrically, so instead of actually calculating the waveform, you can directly set the frequency and phyphox takes care of maintaining the phase of the generated tone. There should be no clicking when changing the frequency and there should be no periodic clicking if the defined frequency does not match up with the sampling frequency. You can find the details in our wiki (https://phyphox.org/wiki/index.php?title...ule:_audio) and you can have a look at the configuration file of the new tone generator in the development branch on githubg (https://github.com/Staacks/phyphox-exper...or.phyphox). Note that the waveform is only calculated in this example to display it to the user.

Also, you can now try a different technique that might be interesting to those of you who are working with resonances. The beta version allows you to generate white noise in the audio spectrum experiment (Settings, below the number of samples), so you can feed the white noise into your resonator and can see the amplified resonant frequencies in the audio spectrum.

You can join the public beta test at https://phyphox.org/download/. The Android version should be available within an hour (maybe a bit longer due to caching of the Play Store app) and the iOS version right after Apple has reviewed this version (probably tomorrow).

[solid]

Thank you Sebastian!
I will try to learn this new possibility which will allow to produce really good product ready to give to students.

[fbouquet]

That is great news, thank you Sebastian!

High school and university students' labs are going to be adapted next year, and phyphox flexibility of building a specific app for one's students is going to be much appreciated by teachers I am sure...

Cheers,

Fred

[fbouquet]

Hello,

I have tried the parametric tone generator, and it works fine (on Android)! I still have to test it on Iphone, and try the noise function...

Thank you again,

Cheers,

Fred

(attached the acoustic resonance program without any clicks)

[solid]

Thank you, Fred.

Finally I have succeeded to upgrade phyphox to the beta version and tried your new version of the program. It works perfectly!