On-axis loudspeaker responses with and without spectral equalisation, measured under optimal conditions and after installation in the array. (a) Top/bottom: On-axis loudspeaker sound pressure level transfer functions without/with FIR filters, measured in the hemi-anechoic chamber. Grey and black lines display individual and mean magnitude spectra, respectively. (b) Comparison of an example loudspeaker’s on-axis sound pressure level transfer function, measured in the centre of the loudspeaker array (grey line) and in the hemi-anechoic chamber (black line), with activated FIR filters.