Audio Credit: Caltech/MIT/LIGO Lab
As the black holes spiral closer and closer in together, the frequency of the gravitational waves increases. Scientists call these sounds "chirps," because some events that generate gravitation waves would sound like a bird's chirp. See: The Sound of Two Black Holes Colliding
This is an Audio Animation above.
The upcoming network of Earth-based detectors, comprising Advanced Virgo, KAGRA in Japan, and possibly a third LIGO detector in India, will help scientists determine the locations of sources in the sky. This would tell us where to aim “traditional” telescopes that collect electromagnetic radiation or neutrinos. Combining observational tools in this way would be the basis for a new research field, sometimes referred to as “multimessenger astronomy” . Soon we will also collect the first results from LISA Pathfinder, a spacecraft experiment serving as a testbed for eLISA, a space-based interferometer. eLISA will enable us to peer deeper into the cosmos than ground-based detectors, allowing studies of the formation of more massive black holes and investigations of the strong-field behavior of gravity at cosmological distances .See: Viewpoint: The First Sounds of Merging Black Holes