Sound machines

Kaila • Baby #1 Sophia 4/19/19🌸🎀

I have a 20month old little girl who has always slept with a box fan on instead of a sound machine. But as she gets older I’m thinking a sound machine would be better especially once she goes to a regular bed so she doesn’t get hurt. What are some good sound machines? And has anyone ever switched from something else as white noise to a sound machine is it a difficult transition?