Two clips touching at their edges do not give you an overlapping passage to compare. Before shaping a crossfade, decide which part of the outgoing sound should coexist with the incoming one.
In a practice project, place two short ambient recordings on separate tracks and overlap them. Listen to the overlap without any fade first. Note whether a recognisable event, such as a door closing, appears twice or becomes confusing.
The Audacity Crossfade Tracks documentation explains its arrangement: the upper selected track fades out while the lower one fades in. Its fade choices can produce different level behaviour in the overlap.
Judge the join in context
Start playback before the transition and continue beyond it. Replaying only the middle encourages you to optimise a moment without hearing how you arrived there.
A longer overlap is not automatically smoother. Two rhythms may fight for attention, or a distinctive background sound may make the location change ambiguous. Shorten the shared interval when it improves the intended transition.
Keep a version before processing, and check the relevant manual for limitations affecting existing envelopes. For your edit note, describe the audible decision: “the second room arrives after the final word.” That is more useful than recording only the effect name.
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