audio - Sampling rate on Android phones -


i trying compare 2 recorded signals @ same frequency different sampling rates. first signal sent , recorded @ 44.1 khz (first spectrogram), , second sent , recorded @ 48khz (second spectrogram). can see, clearer less distortion @ 48khz. m not sure these red parallel signals are. aliasing effect? echoes? though @ 44.1khz signal verifies nyquist-shannon theorem (20khz frequency of signal).

i should mention sent android tablet , recorded nexus 4 phone.

any explanation plz?

enter image description here enter image description here

i believe nexus 4 phone uses 48khz native sampling rate. in other words, first spectrogram audio sampled @ 48khz, , resampled , saved @ 44.1khz. seeing on first spectrogram sampling rate conversion artefacts (from resampling).

the second recording not have resampled, , correspondingly second spectrogram not show such artefacts.


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