The spin-energy E _ { rot } of a Kerr black hole surrounded by a torus may power emissions in multiple windows .
The recently determined true GRB-energy E _ { \gamma } = 3 - 5 \times 10 ^ { 50 } erg indicates a minor fraction E _ { j } / E _ { rot } \simeq 0.1 \% in baryon poor output , here considered as jets along open magnetic flux-tubes from the horizon to infinity .
A major fraction E _ { gw } / E _ { rot } \simeq 5 \% is expected in gravitational radiation from the torus .
A LIGO/VIRGO detection of \alpha = 2 \pi \int fdE _ { gw } in excess of the neutron star limit \alpha ^ { * } \simeq 0.005 promises a calorimetric test for Kerr black holes .
We expect a sample of LIGO/VIRGO detections to obey the distribution of redshift corrected GRB-durations .