The image shows a quiet workshop, yet a loud continuous machine noise sits beneath it. If that sound does not fit the visible activity, it may create a false impression. Ambience should support the location and make the actual situation understandable. Decide which sounds belong to the scene and which occurred incidentally during setup.
Choose a suitable listening position
A wide room view and a close machine detail may need different sound perspectives. First record a steady overall atmosphere from a plausible position. Capture a separate closer recording for an important detail afterwards. Keep microphones outside hazardous working areas and do not alter running machinery merely to experiment with sound.
Listen for your own movement, clothing and cables during capture. The operator can spoil an otherwise quiet room recording. Leave enough space before and after an individual event for clean editing later. Do not begin only when the door is already closing.
Separate continuous background from events
Steady room sound works as a background. A recognisable hammer strike, telephone ring or shout is an event with its own meaning. Save and name these separately. This prevents a recurring signal accidentally becoming an allegedly unobtrusive loop in editing.
With stereo recording, check orientation. A left-to-right movement should not appear reversed merely because the microphone was turned around. Note position and facing direction alongside the filename. These details are particularly useful when someone else edits the pictures later.
Balance it beneath speech
Initially place the ambience quietly under the scene and raise it only enough to establish the location. In an explanatory video, intelligible speech usually takes priority. Also listen through small loudspeakers, where some noise components may compete more strongly with consonants.
A change of location can remain audible. Do not carry the same background across every room simply to maintain one continuous track. Short crossfades can soften transitions without concealing the difference. Retain untouched ambience recordings so another duration or perspective can be selected later.