Detection
Threshold
BeoLab 90
turns ON
BeoLab 90
turns OFF
Time Out
Audio level at input
Time
Audio Signal
Figure 6.4: The “Detection Threshold” and “Time Out” parameters
6.2.7
Input Impedance
If the BeoLab 90’s RCA Line input is
connected to a device’s headphone
output that uses a Class-D amplifier,
there may be instances where this
causes the noise floor to rise audibly.
This is caused by the input impedance
of the BeoLab 90 being much higher
than that which is expected by the
headphone amplifier’s designer. In
order to correct this problem, the input
impedance of the RCA input can be set
to a low value of 50
Ω
.
However, if the input impedance of the
RCA input is set to 50
Ω
and it is
connected to a device’s standard
low-impedance line output, this may
have a detrimental effect on the signal.
For example, the maximum possible
output level will be reduced. In some
cases, incorrectly setting the input
impedance to 50
Ω
may also cause
distortion of the audio signal.
Options
50
Ω
, 50 k
Ω
Factory Default
50 k
Ω
Note that the Input Impedance control
is only available for the RCA line input.
6.2.8
Control Volume of
S/PDIF (or Optical) input
using Power Link
Bang & Olufsen audio products that are
able to send the audio signal on an
S/PDIF output additionally send the
volume setting on the data connection
included in the Power Link cable. This is
used for various reasons. One primary
example of this is current customers
who connect a BeoSound 9000 to a
pair of loudspeakers such as BeoLab
5’s or BeoLab 90’s via a S/PDIF digital
connection. Since the BeoSound 9000
does not apply volume regulation to
the S/PDIF output, the volume setting
must be sent separately on the Power
Link cable and applied to the audio
signal inside the loudspeaker instead.
This parameter on the BeoLab 90
allows customers to use the volume
control of a Bang & Olufsen source
(sent via a Power Link connection) and
apply it to an audio signal coming into
the BeoLab 90 via its S/PDIF input.
Note that, in order for this option to
function properly, the S/PDIF input
must be assigned a higher priority than
the Power Link input in the
This function is also independently
available for signals on the Optical
input.
When the volume of the BeoLab 90 is
controlled by an external Power Link
source, the volume wheel in the
BeoLab 90 interface is greyed out and
will not respond to touch commands. It
does, however, display the volume
setting assigned to the BeoLab 90 by
the Power Link data signal.
Options
Enabled / Disabled
Factory Default
Disabled
6.2.9
USB Volume enabled
When the BeoLab 90 is connected
using USB Audio to an audio source,
you have the option of using the
source’s volume as an external control
for the gain of the loudspeaker. This
also means that the volume of the
BeoLab 90 (set by its remote control)
would be reflected on the user
interface of the audio source or
software player.
However, this external control of the
BeoLab 90 may not be desirable in all
situations. For example, it is very easy
to instantly change the volume of a
software audio player to maximum,
which will be surprisingly loud with a
BeoLab 90 if the change was
accidental. It also may be preferable to
set the BeoLab 90 to a static (e.g. low)
volume setting and to have an
independent adjustment on the source
device. In these cases, the
USB Volume
Enabled
should be set to Disable.
Options
Enabled / Disabled
Factory Default
Disabled
Note that the USB Volume control is
only available for the USB Audio input.
6.3
Connection Panels
The connection panels on the Master
and Slave BeoLab 90’s are slightly
different in that audio signals can only
be connected to the Master
loudspeaker. The audio signal
connections from your source devices
should be connected to the Master
loudspeaker. The only audio input on
the Slave loudspeaker is the DPL or
Digital Power Link input.
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