Neumann.Berlin KH 810 - Technical Information & Glossary

30 | KH 810/870
Technical information & glossary
Absolute
level
In Europe, the absolute level of 0 dBu is -18 dBFS (EBU standard R68). In the US, +4 dBu is -20 dBFS
(SMPTE standard RP155). These dBu values should lead to the following sound pressure levels:
Application Sound pressure level
Film 85 dB(C)
Broadcast 79 dB(C) (reference level)
Music No defined reference levels
Near field loudspeakers can be as close as 1 m from the listening position, whereas loudspeakers in
a Dolby certified movie mixing room should be at least 5 m from the listening position.
In the examples below, it is assumed that the listener is inside the room radius and thus the sound
field decays according to 20log
10
( r ), however this may not always be the case.
Absolute voltage level of input signal
0 dBu
(0.775 V)
+4 dBu
(1.23 V)
Setting SUBWOOFER GAIN | INPUT GAIN L
-1 dB -5 dB
SettingSUBWOOFER GAIN | OUTPUT LEVEL K
100 100
Listening distance [m] (dB change) 5 m (-14 dB) 5 m (-14 dB)
Measured output level in dB SPL at 1 m 85 dB SPL 85 dB SPL
Maximum input signal before activation
of the protection system
17 dBu 17 dBu
Absolute acoustic level calibration for signal channels is generally achieved using a sound level meter
set to “C-weighted” and “Slow”. Play a broadband pink noise test signal set to -18 dBFS (Europe) or
-20 dBFS (USA) on the console meters and measure the sound pressure level at the listening posi-
tion. Then adjust each channel’s source level, not the loudspeakers and subwoofer(s) so that the
above stated sound pressure levels are achieved.
Acoustical
axis
The acoustical axis is a line perpendicular to the subwoofer’s front panel along which the microphone
was placed when tuning the subwoofer’s crossover during design. The acoustical axis is located at the
midpoint of the KH 810’s bass driver or at the midpoint of the bass drivers of the KH 870.
Acoustical
controls
The acoustical controls are low-order analog filters designed to compensate for some of the acoustical
issues commonly found in listening environments. The acoustical controls’ settings will depend on
the subwoofer’s location and will probably be dierent for the same subwoofer type positioned in dif-
ferent locations in the same room. When calibrating subwoofers there are three areas requiring atten-
tion: in-room response, level relative to main loudspeakers, and phase relative to main loudspeakers.
EN