Coarse grid finite-difference schemes do not allow for general source and r
eceiver positions. This problem is here solved with optimized operators wit
h general phase-shift properties. These operators are bandlimited represent
ations of the Dirac delta function and the derivative of the Dirac delta fu
nction. The scheme is tested for a single source and a source array. The re
sulting finite-difference solutions are for both cases close to the analyti
cal solution.