General Antonyms:
* Soothing
* Calming
* Reassuring
* Peaceful
* Tranquil
* Comforting
Antonyms related to specific types of disturbing:
* Pleasing (if something is disturbing because it is unpleasant)
* Encouraging (if something is disturbing because it is discouraging)
* Inspiring (if something is disturbing because it is disheartening)
* Uplifting (if something is disturbing because it is depressing)
More specific antonyms:
* Invigorating (if something is disturbing because it is dull)
* Enlightening (if something is disturbing because it is confusing)
* Harmonious (if something is disturbing because it is chaotic)
The best antonym for "disturbing" will depend on the specific context in which the word is used.