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| KH 805
Signal rout-
ing
The KH 805 has two input channels (LEFT, RIGHT/LFE/DAISY CHAIN) and three output channels (LEFT,
RIGHT, DAISY CHAIN) . After the electronically balanced input stages, there are two 4th order 80 Hz
high pass filters for the main channels followed by two electronically balanced output stages . The
signal connected to the left input is always routed to the subwoofer via a 4th order 80 Hz low pass
filter and to the left output via an 80 Hz 4th order high pass filter . This is the same for the right input
when the input mode is set to RIGHT .
All outputs (main channels and daisy chain) have protection circuits to avoid power on/off noises: the
outputs switch on after a short delay when mains power is applied and mute instantaneously when
mains power is removed .
If you select the corresponding mode, there is also 120 Hz low pass filtering for an LFE channel or a
wide input if you have an external bass manager (more details can be found on page 19) . Addition-
ally a daisy chain mode allows you to connect additional subwoofers .
Crossover
Using 4
th
order filters, the crossover divides the input signal of each channel into two bands for repro-
duction by the subwoofer or the main loudspeakers . The crossover frequency is fixed at 80 Hz for all
the main channels and can be bypassed when required . This frequency was chosen to balance the
conflicting requirements of having a high crossover frequency to relieve the main loudspeakers of
their low frequency duties thereby reducing distortion, and of the need to have a low crossover fre-
quency to minimize the chances of localizing the subwoofer thereby giving greater flexibility when
placing the subwoofer in the room . In addition, by choosing 80 Hz, there is a compatibility with the
replay conditions commonly found in consumer products .
Driver
Long throw, efficient, low distortion driver ensures a clean sound quality even at high replay levels .
The driver is loaded by the internal volume of the cabinet and is magnetically shielded for use next to
CRT screens and magnetic storage media .
LFE channel
“Low Frequency Effects” (Dolby) or “Low Frequency Enhancement” (dts) . The LFE channel has a lim-
ited bandwidth . Because of the limited frequency range of the LFE channel, it is referred to as “ .1”
when describing, for example, a 5 .1 system . The designation “LFE channel” always refers to the source
and not to the loudspeakers .
Power
amplifier
The high efficiency power amplifier of the KH 805 minimizes power dissipation and is run in bridged
mode to minimize distortion .
Protection
system
An extensive protection system prevents damage to the subwoofer if high signal levels are applied to
the input . The LED POWER ON
I
changes from green to red when the protection system is active . In
this case, reduce the input signal level . If this happens regularly, use a larger subwoofer with a higher
SPL output or add more subwoofers to the system to increase the LF headroom .
The protection system consists of thermal and peak limiters for the amplifier and thermal modeling of
the driver . The protection system is not a compressor, it is designed to protect the subwoofer from
damage . The protection system cannot protect against sustained abuse of the loudspeaker system,
i .e . playing the subwoofer for long periods of time with the LED POWER ON
I
lighted up red . Please
avoid consistent abuse of the subwoofer to not affect the long service life of the product .
