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9S User manual


Switching the subwoofer on

Once you have ensured yourself that all necessary connections have been made, the subwoofer and the connected components can be switched on.

  1. Connect the subwoofer to the mains power.
  2. Switch the subwoofer on with the main POWER switch on the rear panel.
  3. The status LED on the rear of the subwoofer will light up red.
  4. Select a power mode with the Power switch on the rear panel.

Power modes

On: the subwoofer is switched on permanently

Auto: when a music signal is detected, the internal amplifier is activated automatically. The status LED on the back of the subwoofer will light up green. As long as a music signal is available on the subwoofer’s input, it will remain switched on.

After 15 to 20 minutes of not sensing any input music signal, the subwoofer will switch itself to Standby mode automatically. The status LED on the back of the subwoofer will light up red.


To switch the subwoofer completely off, set the main POWER switch to the OFF position.

Adjusting the volume (Gain)


High Sound Levels!

High sound levels can cause auditory defects. To avoid auditory period of time defects, do not listen to high sound levels over a longer period of time.

The correct volume setting is an important aspect in achieving a well balanced speaker combination.

To adjust the gain

Adjust the Gain control, until correct setting is reached.


You cannot adjust the volume when the subwoofer is in slave mode. In this case the volume is controlled by the setting of the master subwoofer.

Selecting the subwoofer cut-off frequency (Lowpass)

The Lowpass control allows the frequency range of the subwoofer to be defined. Above the selected frequency the sound level decreases rapidly. The correct setting of this cut-off frequency is important for a well balanced combination of subwoofer and speakers.

To select the cutoff frequency

Set the Lowpass control to the desired frequency between 50 and 150Hz.


The Lowpass only works on SAT/SUB input.

Perhaps subwoofer cut-off frequency is already set in the bass management of your source. Please refer to the operating manual of your source. In general use only one bass management system.

You should also heed the instructions given in the operating manual of your loudspeakers.

Setting the phase (Phase)

With the phase settings you can adjust the phase relationship between the subwoofer and main speakers. If either subwoofer or main speaker are slightly out of phase in relation to the other, it can result in decreased bass output in the frequency response area where they overlap each other.

Red: Combined frequency response
Grey: Subwoofer
Black: Main speakers

The phase relationship between subwoofer and satellite speakers is very dependent on relative distance, construction and working principles of the main speakers. The figure above shows a case whereby phase of the subwoofer and main speakers are incorrect in the critical overlap area, thus significantly reducing acoustic output in the listening room in that area.

To find the correct phase setting

  1. Play a bass-rich track which also covers the overlap area.
  2. Toggle the Phase switch between 0° and 180°. Choose the setting for which you experience the most bass.


You can not set the phase if the subwoofer is in slave mode. In this case the phase in controlled by the setting of the master subwoofer.

Setting the satellite cut-off frequency (Highpass)

Depending on the bass capabilities of the speakers, the frequency range of subwoofer and speakers can overlap between 50Hz and 150Hz. A bump or a gap in the frequency response and thus a lower sound quality will be experienced if the system is not matched properly. In addition, small speakers and low powered amplifiers will particularly be affected by the low frequency signals, which again has a negative effect on the sound quality. Therefore it makes sense to limit the bass range of the connected speakers (called “satellites” in this case) by a highpass filter. The 9S provides three settings to achieve this:

  • Flat = no limitation
  • 60Hz = frequencies below 60Hz are cut off.
  • 80Hz = frequencies below 80Hz are cut off.

To set the cut-off frequency

Switch Highpass control to needed position.