It's the sound of non-copyrighted music

Not being allowed to use copyrighted sound (very annoyingly) our dreams of using 'Tea for Three plus One'- the original sound used in The Woman in Black- were shattered. However- with the help from Ms Foster- we found Epidemic Sound, an amazing site FULL of non-copyrighted sounds! By picking a genre and mood, the site directs you to sounds matching your description!