I too am hearing impaired. The first ones we had were not as loud as the newer ones are. Newer ones also have batteries that can be replaced after a year. The Tile app on your phone which sends the signal also has a circular image which fills in, getting greener as you get nearer the lost Tile.
Tiles also ping each other whenever you are near someone else who has a Tile, so if he had left his keys at a restaurant and someone nearby also had a Tile, my phone app would indicate where his keys Tile was last pinged.
Their website probably gives a much clearer explanation than I do.