Klein + Hummel 0810 Bedienungsanleitung Seite 20

room. When calibrating subwoofers there are three areas requiring attention: in-room response, level relative the
main loudspeakers, and phase relative to main loudspeakers.
For systems containing subwoofers, it is highly recommended to use an acoustical measurement system to set
the acoustical controls (gain, parametric and low cut filters, and phase) in the most appropriate way to
compensate for the subwoofer's location. This is especially true of the parametric equalizer's controls which are
very hard to set by listening.
The acoustical control set consists of the following:
• The Low Cut control reduces the output level of the subwoofer in ranges of 30 Hz using a peak filter centered
on 30 Hz and with a Q of 1.5 – see graph below. This is used to compensate for a rise in level seen at very low
frequencies due to a lack of LF damping.
Low Cut acoustical control
• The Parametric Equalizer is a single stage PEQ filter with gain (+4...-12 dB), frequency (20...120 Hz) and
Q (1...8) controls designed to control nonlinearities seen below 120 Hz – see graph above. These
nonlinearities can come from boosts caused by constructive interference or strong room modes. It is possible
to bypass the parametric equalizer using the bypass switch.
• The Subwoofer Phase controls consist of a 0° / -180° switch and 0° / -45° / -90° / -135° switch. This applies a
very short delay (45° at 80 Hz = 1.56 ms) to the subwoofer output, and gives a positional resolution of
0.54 m (1' 9"). These controls are used to acoustically realign the subwoofer with the main loudspeakers
when they are positioned at different distances from the listening position.
• The subwoofer's output level is controlled using the Subwoofer Gain controls. This consist of a finely
graduated Input Gain (+2 to -12 dB) potentiometer and a coarse Output Level (100 or 114 dB SPL at 1 m)
switch. This allows the subwoofer to be matched to a wide range of equipment outputs whilst maintaining
the desired acoustical output. It can also compensate for level differences due to acoustical loading and the
distance of the subwoofer from the listening position compared to the main loudspeakers. The default
settings are "0 dB" and "100 dB SPL at 1m". This gives an output level of 100 dB SPL at 1m when the input
signal is 0 dBu (0.775 V). The most sensitive setting (most acoustical output for a given input voltage)
is "2 dB" and "114 dB SPL at 1m", and the least sensitive setting is "-12 dB" and "100 dB SPL at 1m".
Input Gain
Potentiometer [dB]
-12 dB
-10 dB
-8 dB
-6 dB
-4 dB
-2 dB
0 dB
2 dB
Operating Manual O 810 / O 870
Acoustic output level [dB SPL] of the loudspeaker at 1m
when input signal is 0 dBu
Output Level switch = "100 dB"
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90
92
94
96
98
100 (default)
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Parametric Equalizer acoustical controls
Output Level switch = "114 dB"
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104
106
108
110
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114
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