Sound isn't often considered when designing a garden. We're very attuned to sounds when we're walking through a forest, but it takes a back seat to the other senses, in a garden. That doesn't mean it's not there. Probably the most heralded garden sounds are birds chirping, water gurgling and the wind rustling ornamental grasses.
Sound adds a surprising dimension to a garden. More often than not, it surprises or startles you. But listening for the sounds of your garden keeps you alert and so, more in tune with the other elements of your garden and of the seasons.
Water, wind and wildlife play a big part in the music of a garden, but I'll add one more; walking. You add sounds to your garden just by being there, whether it's crunching, clanking or rustling, sound is an element you contribute and a chance to become a part of the combined senses that bring your garden to life.