© Genelec Oy, 2006. Published in Resolution Magazine, Sweet Spot, p 46-47, April 2006, V5.3
4
problem in the monitor itself. The
reasons are either in the room or in
the placement of the monitor into the
room, or both. However, the
magnitude of the aberrations a room
or wrong placement can cause may
exceed any reasonable correction
capacity, and hence everything possible
should be done to remove the root causes. As
said in the beginning, it is better to prevent the
errors from happening than correct them
afterwards. Also the microphone works in a
different way to an ear, so the correction
algorithms shall be carefully considered.
The Genelec AutoCal
TM
is a fully automated
acoustical calibration tool for a single room
multi-loudspeaker system. This software was
preceded by the DIPtimiser work mentioned
earlier. The AutoCal system produces
loudspeaker-generated test signals recorded
by a high quality calibration microphone to
determine correct acoustical alignments for
every loudspeaker and subwoofer on the GLM
control network. AutoCal uses a sine tone
sweep generated in each monitor and
subwoofer. This sweep is recorded using
Genelec 8200A Calibration Microphone at one
(SinglePoint
TM
) or more positions
(MultiPoint
TM
). The frequency response for
every monitor is calculated. AutoCal then
determines the correct acoustical settings for
flat frequency response at the listening position
(or over an area), aligns for equal delay from
all monitors to the primary listening position,
and aligns output levels and subwoofer
crossover phases.
AutoCal sets the four notch filters in the 7200
series subwoofers and four notch filters in the
8200 series monitors along with two high
frequency and low frequency shelving filters.
The automated calibration procedure aligns
distances within 1.5 cm (3/4”) and levels to
within 1 dB. A
typical 5.1 system
takes about five
minutes to
calibrate.
The technology in
Genelec 8200 and
7200 DSP loud-
speakers is not
there to correct
and fix mistakes in
the electro-
acoustic design
but rather to offer improved usability and
flexibility for often complicated and rapidly
changing productions and to provide an
efficient tool for integrating loudspeakers into
the acoustics of the listening environment. The
monitoring system should adapt to the working
needs and situations as far as possible, not the
other way around. Built on the solid acoustical
foundation of the 8000 and 7000 series
products, these new products are the logical
step in the line of development to make the
end user’s work easier, more enjoyable and
more productive.
Written by Christophe Anet & Ilpo Martikainen
© Genelec Oy, 2006.
