Architecture and design guru William T. Georgis designed his dramatic pool for his private West Coast getaway. A raised planter ingeniously created planting space at the foot of a large retaining wall, which we filled with statuesque junipers and striped flax. Water spilling from pin jets into the pool is a lovely soundtrack in the already tranquil spot.
From Gardens are for Living: Design Inspiration for Outdoor Spaces by Judy Kameon
How can I interpret “soundtrack” here? Does it mean background sound? Does it imply the sound makes the spot even more tranquil?
Soundtrack:
the sounds, especially the music, of a film, or a separate recording of this:
https://dictionary.cambridge.org/dictionary/english/soundtrack