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Hello,
I want to use Phyphox Noise Intensity with my students but I don't understand why the measures (SPL db) are always negative. Is it because the sensor is not calibrated ? How can I get positive values without calibrating the sensor ?
Thank you for your help.
Philippe Schmidt
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The audio amplitude experiment could only provide relative intensity information if the sensor is not calibrated. So: yes – and you can‘t. Please find some details in the experiment info via the three vertical dots menu.
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(05-01-2020, 07:19 PM)Jens Noritzsch Wrote: The audio amplitude experiment could only provide relative intensity information if the sensor is not calibrated. So: yes – and you can‘t. Please find some details in the experiment info via the three vertical dots menu.
Thank you !
Philippe
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Get negative dB?
Calibrate.
How to calibrate?
Get positive dB from other soundmeter app.
Posts: 543
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Institution: RWTH Aachen University
(09-09-2020, 09:45 AM)Roland Van Kerschaver Wrote: Get negative dB?
Calibrate.
How to calibrate?
Get positive dB from other soundmeter app.
Thanks, Roland, for pointing this out. That has fallen short in my reply.
For the sake of completeness I also add our “disclaimer”, see phyphox.org/wiki/index.php/Experiment:_Audio_Amplitude:
“Even a well calibrated experiment is still limited in its accuracy as the experiment does not take into account the base noise, the spectral dependency of the microphone, non-linear responses and directional dependencies. So, this experiment may be suitable for simple educational purposes, but for serious measurements you will either need a dedicated app for your device or, much better, professional equipment.”
