Does FIRmaker require on-site measurements?
No, FIRmaker is using high-resolution loudspeaker modeling data to simulate the performance of the system. Based on that FIRmaker computes optimal FIR filters for each DSP channel. Extensive tests in the field have shown that the accuracy of the simulation predicts system performance better than measurable differences of the real setup.
On-site measurements e.g. with SysTune or EASERA can, of course, be performed additionally to refine the performance and align the array to other parts of the sound system.