Genelec Frequency Response Optimisatio, Manual

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GOLDBERG AND MÄKIVIRTA AUTOMATED IN-SITU EQUALISATION
AES 23RD CONFERENCE, May 23-25, 2003 9
reduced after equalisation, which indicates that equali-
sation compensates well for the loudspeaker loading.
A better match across subbands of the average sub-
band median level demonstrates that equalisation has
improved the broadband flatness. The largest im-
provement is seen in the three-way loudspeakers. In
the two-way systems the equalisation has improved
broadband flatness only marginally as the subband
median levels do not show major signs of change. The
broadband flatness improvement is mainly the result
of better alignment of the LF subband with the MF and HF subbands. This indicates that the equalisation
has not only reduced the variation inside individual
subbands but also improved the broadband flatness of
the acoustical response, translating to a reduced
colouration of the audio at the listening position.
For all loudspeakers pooled together (Figure 3), the
equalisation reduces the variance in the median level
for the LF subband. A similar outcome is noted sepa-
rately for each loudspeaker type. However, only in the
three-way systems is an improvement seen also in the
MF and HF subband variance.
25% to 75% Percentile Difference
Change due to Equalisation - All models
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
RMS Deviation
Change due to Equalisation - All models
-5
-4
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
25% to 75% Percentile Difference
Change due to Equalisation - Small models
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
RMS Deviation
Change due to Equalisation - Small models
-5
-4
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
25% to 75% Percentile Difference
Change due to Equalisation - 2-way models
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
RMS Deviation
Change due to Equalisation - 2-way models
-5
-4
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
25% to 75% Percentile Difference
Change due to Equalisation - 3-way models
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
RMS Deviation
Change due to Equalisation - 3-way models
-5
-4
-3
-2
-1
0
1
Broadband LF MF HF
Level, dB
Figure 4. Change in sound level deviation due to equalisation. For each subband, quartile difference and RMS de-
viation from the median. The error bar indicates the standard deviation.