A method for adjusting a cross-over frequency of a loudspeaker system, the loudspeaker system comprising at least a first loudspeaker for frequencies below the cross-over frequency and a second loudspeaker for frequencies above the cross-over frequency, wherein the method comprises: - matching level of the first loudspeaker with the second loudspeaker using a first test signal by: providing the first test signal to the first loudspeaker to produce audible signals sweeping a first frequency range; receiving the audible signals; determining a room frequency response of the first loudspeaker on the basis of the received signals; measuring the level of the received signals; providing the first test signal to the second loudspeaker to produce audible signals sweeping a second frequency range; receiving the audible signals; determining a room frequency response of the second loudspeaker on the basis of the received signals; measuring the level of the received signals; using the measured levels to match the level of the first loudspeaker with the second loudspeaker; - compensating the room frequency response of the first loudspeaker and the room frequency response of the second loudspeaker on the basis of the determined room frequency responses; characterized in that it further comprises: - measuring the compensated room frequency responses using a second test signal; computing an estimate of summed total harmonic distortion for the first loudspeaker and an estimate of summed total harmonic distortion for the second loudspeaker; - determining a maximum frequency for the first loudspeaker by examining the measured compensated frequency response of the first loudspeaker and determining a roll-off point of the first loudspeaker; and - determining a minimum frequency for the second loudspeaker by examining the measured compensated frequency response of the second loudspeaker and determining a roll-off point of the second loudspeaker; and - searching a cross-over frequency between the minimum and maximum frequency that results in a minimum cumulative total harmonic distortion energy at one or more sound pressure levels. - matching level of the first loudspeaker with the second loudspeaker using a first test signal by: providing the first test signal to the first loudspeaker to produce audible signals sweeping a first frequency range; receiving the audible signals; determining a room frequency response of the first loudspeaker on the basis of the received signals; measuring the level of the received signals; providing the first test signal to the second loudspeaker to produce audible signals sweeping a second frequency range; receiving the audible signals; determining a room frequency response of the second loudspeaker on the basis of the received signals; measuring the level of the received signals; using the measured levels to match the level of the first loudspeaker with the second loudspeaker; providing the first test signal to the first loudspeaker to produce audible signals sweeping a first frequency range; receiving the audible signals; determining a room frequency response of the first loudspeaker on the basis of the received signals; measuring the level of the received signals; providing the first test signal to the second loudspeaker to produce audible signals sweeping a second frequency range; receiving the audible signals; determining a room frequency response of the second loudspeaker on the basis of the received signals; measuring the level of the received signals; using the measured levels to match the level of the first loudspeaker with the second loudspeaker; - compensating the room frequency response of the first loudspeaker and the room frequency response of the second loudspeaker on the basis of the determined room frequency responses; characterized in that it further comprises: - measuring the compensated room frequency responses using a second test signal; computing an estimate of summed total harmonic distortion for the first loudspeaker and an estimate of summed total harmonic distortion for the second loudspeaker; - determining a maximum frequency for the first loudspeaker by examining the measured compensated frequency response of the first loudspeaker and determining a roll-off point of the first loudspeaker; and - determining a minimum frequency for the second loudspeaker by examining the measured compensated frequency response of the second loudspeaker and determining a roll-off point of the second loudspeaker; and - measuring the compensated room frequency responses using a second test signal; computing an estimate of summed total harmonic distortion for the first loudspeaker and an estimate of summed total harmonic distortion for the second loudspeaker; - determining a maximum frequency for the first loudspeaker by examining the measured compensated frequency response of the first loudspeaker and determining a roll-off point of the first loudspeaker; and - determining a minimum frequency for the second loudspeaker by examining the measured compensated frequency response of the second loudspeaker and determining a roll-off point of the second loudspeaker; and - searching a cross-over frequency between the minimum and maximum frequency that results in a minimum cumulative total harmonic distortion energy at one or more sound pressure levels.