Is hiss in the recording being automatically removed?


I have just upgraded from Fedora 33 (X / XFCE / ALSA) to 34 (Wayland / Sway / PipeWire etc) and have pretty much got all the UI stuff sorted out but I notice when I record anything locally eg with Audacity, that there is a noticeable hiss on the recordings but if I use exactly the same setup to record online eg with a mic testing site or with sessions saved on DropBox - there is NO hiss! Does this mean that there is some post-processing going on to remove the hiss (like what can be done with Audacity post recording)?