Fuel filter...
An example of psychological noise is when someone is preoccupied with personal worries or stress, making it difficult for them to fully concentrate on a conversation or message they are receiving. This internal distraction can interfere with their ability to encode and comprehend the information being communicated.
you must focus, focus and focus some more, shut out the noise that is surrounding you.
wheel bearing
you must focus, focus and focus some more, shut out the noise that is surrounding you.
X-files
Take it to a repair shop and get it fixed!
Ask your plumber to install a water hammer arrester.
The X-Files
Noise is common from any engine, the TYPE of noise is what you should worry about. Is it a knocking noise? hum? squeak? rattle?
A clock is the answer
Noise blocking headphones insulate your ear from outside sounds to reduce the amount of outside noise allowing you to better hear and focus on the sounds from the headphones.
There may be some drag on the AC clutch when it is disengaged as the clutch 'free-wheels' during this time. When you engage the AC ,the clutch 'locks up' and the noise disappears. If the noise gets worse you may need to replace the clutch, if it stays the same and it not very loud, I would not replace it.