Automated In-situ Frequency Response
Optimisation of Active Loudspeakers
Andrew Goldberg
1
and Aki Mäkivirta
1
1
Genelec Oy, Olvitie 5, 74100 Iisalmi, Finland.
ABSTRACT
This paper presents a novel method for robust automatic selection of optimal in-situ acoustical frequency response
within a discrete-valued set of responses offered by room response controls on an active loudspeaker. A frequency
response measurement is used as the input data for the algorithm. The rationale of the room response control system
is described. The response controls are described for each supported loudspeaker type. The optimisation algorithm
is described. Examples of the optimisation process are given. The efficiency and performance of the algorithm are
discussed. The algorithm dramatically improves the speed of optimisation compared to an exhaustive search. It
improves the acoustical similarity between loudspeakers in one space and performs robustly and systematically in
widely varying acoustical environments. The algorithm is currently in active use by specialists who set up and tune
studios and listening rooms.
1. INTRODUCTION
This paper presents a system to optimally set the room
response controls currently found on full-range active
loudspeakers to achieve a desired in-room frequency
response.
The active loudspeakers [1] to be optimised are
designed and calibrated in anechoic conditions to have
a flat frequency response magnitude within the design
limits of ±2.5 dB. When a loudspeaker is placed into
the listening environment, response changes due to the
loudspeaker-room interaction. To help alleviate this,
these active loudspeakers incorporate a pragmatic set
of room response controls accounting for some
common acoustic issues found in professional
listening rooms.
Although many users have the facility to measure
loudspeaker in-situ frequency responses, they often do
not have the experience of calibrating active loud-
speakers. Even with experienced system calibrators a
