I played a 1khz sinus wave.
Why do I see a completely different amplitude as soon as I activate oversampling?
In addition, the amplitude oscillates in the low frequency range, when oversampling is activated.
By how much are you oversampling this file?
Also do you have this particular 1kHz sine wave tone available to share for testing purposes?
Majority of the ones I have gotten for free from the web are at 0dBFS, and their peak level does not change or decrease in any appreciable way when oversampling (but my device's display is a paltry 800x480 instead of 3200x1440 so you can definitely see more granular changes than I can).
You have Follow Source Frequency enabled under Spectrum Analyzer settings. Should you disable this, you can see that when Neutron outputs at higher and higher sampling rates, Spectrum Analyzer merges the amplitudes of lower frequencies together into single band(s).
For example, native playback of 44.100 kHz file, the leftmost amplitude is a single band ranging from 20 to about 40 Hz.
When I oversample (X2), the leftmost amplitude is a single band ranging from 20 to about 80 or 90Hz.
(These screenshots are all at different places within same 44.100 kHz file, so amplitudes will vary, this is more to show the width of the bands)
Follow Source Frequency (In Spectrum View) Disabled - Oversampling (X2) Enabled
Follow Source Frequency (In Spectrum View) Disabled - Oversampling Disabled
Follow Source Frequency (In Spectrum View) Enabled - Oversampling (X2) Enabled
Follow Source Frequency (In Spectrum View) Enabled - Oversampling Disabled