User's Manual

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Sub15 Manual / English
On the front side you will find indicator LEDs for the operating mode and
the protective circuit. Controls for the satellite filter, a phase switch and Sub
Level/Filter are located on the rear panel of the subwoofer. The following
tips are intended to assist you at using the controls in the best manner.
5.1 LEDs on front panel
There are two LEDs on the front. The upper LED
indicates the operating mode. In case the subwoofer
receives an overload the lower LED will flash red
indicating the function of the protective circuit.
5.2 Controls on the rear panel
a) Subwoofer Phase
With the Phase Switch you can alter the phase of
the subwoofer relative to the satellites. That means
to change the polarity of the subwoofer. Depending
on the distance between woofer and satellites,
either 0° or 180° may be the better position. We
recommend trying out which position sounds better
within your system.
b) Satellite Filter
The satellites in a system can be driven full range or with a 85 Hz high
pass as recommended by Dolby® laboratories for use in surround set-
ups. Recommendation: the main signal should go into the Subwoofer.
Connect your satellites to the Subwoofer output, either via XLR
symmetrical or RCA asymmetrical. In many cases, clarity and dynamic
range of the speakers can be improved if they do not reproduce very
low frequencies since they do not have to deliver big amplitudes.
Please note: If you alter the frequency it is advisable to check if an alteration
of the phase improves the sound quality.
5. Controls
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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!
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, reflective surfaces (like walls) in close range of the subwoofer should
be avoided 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 combine their force with the first wave(s):
a vicious circle that results in local imbalances of the particular frequencies.
4.3 Finding the best 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