This cell only responded to higher frequencies, especially at low volume levels; increased volume expanded the cell's frequency range of response. (sciencedaily.com)
«This makes it possible to communicate at much lower volume levels than before.» (sciencedaily.com)
Sounds with high volume and rich frequency spectrum affect the majority of the boids, while low volume level and less quantity of active frequencies produces subtle visual variations and a slower graphic evolution. (discovermagazine.com)