We show how, combining their outputs, at least six resonant bar antennae give with isotropic sensitivity the amplitude, polarization, and direction of propagation of a burst and test for two distinctive properties of the Riemann tensor: transversality and tracelessness. If not located at the same site, to exert the two vetoes, the burst arrival times on three antennae must be known; we show how to determine them. Then in addition the propagation of the burst at light velocity is tested