User's Manual

9
Sub7 Manual / English
On the front side you will find two potentiometers, one for the volume and one for the
crossover frequency. Both the volume and the frequency can also be controlled by
the remote control. On the rear side, there are more controls (satellite filter, phase
switch, mode). The following tips are intended to assist you at using the controls in
the best manner.
5.1 Controls on the front panel and Remote control
a) Volume
Input Sensitivity control from -60 dB to +6 dB relative
to 775 mV when used via the symmetrical XLR input
or relative to 250 mV when used via the asymmetrical
Cinch (RCA) input.
b) Frequency
The upper frequency limit of the unit is variable and
can be set to any value between 50 and 150Hz.
The 85Hz marker indicates the recommendation of
Dolby® labs for surround sound settings. In many
cases, a slightly lower crossover frequency delivers
tighter bass response, for typical near-midfield
monitors we recommend 70 to 75Hz as upper limit
(i.e. -3 dB point in the frequency response).
Please note: If you alter the frequency it is advisable
to check if an alteration of the phase improves the
sound quality.
5. Controls
FREQ
VOLUME
+
+
8
It is common knowledge that low frequencies (below about 100Hz) are non-directional,
meaning they can hardly be located by the listener. It is, however, a common misunder-
standing that therefore the placement of a subwoofer does not matter. It does matter.
Due to the fact that every room (geometry, furniture, etc.) is unique, the following de-
scriptions intend to be a first introduction to the subject. The aim is to assist you tack-
ling the most common problems with subwoofers and room acoustics, notably interfer-
ence and standing waves.
4.1 Distance to satellites
In most set ups it is advisable to place the subwoofer not too far from the satellites
to minimize the chance of Interferences. Interference means the superposition of
two or more waves resulting in an attenuation/cancellation or enhancement of the
specific frequency/frequencies.
Furthermore, big refelexion faces in close range of the subwoofer should be avoid-
ed if possible.
4.2 Walls/Distance to walls
Generally, every wall in relative close distance to the subwoofer enhances its
sound pressure by about 6 dB. For instance, placing the subwoofer in a corner of
a room will make it about 18 dB louder. It is likely that this will result in an impair-
ment of the precision of the musical reproduction.
Another problem related to the geometrics of the room concerns the so called
‘standing waves’. These are sound waves being reciprocated between reflecting
objects, so they ‘stand’ (don’t seem to move) in between these objects. The speak-
er continues to produce new waves that combines its force with the first wave(s): a
vicious circle that results in local imbalances of the particular frequencies.
4.3 Finding the optimum position
Give it a try! The most important tool for finding the best position for your sub-
woofer are your ears. There are two rather easy ways:
You can determine your listening spot first and then compare the sound of the
subwoofer at different positions.
Another option is to place the subwoofer at the listening position and then move
around. Whereever the sound is the best the subwoofer should be positioned.
4. Subwoofer Placement