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18S User manual

Control and configuration

Subwoofer controller

Rotary controller:

  • Rotate to select.
  • Press to confirm.
  • Hold to exit menu.

Configuration and Use

With the 18S subwoofer positioned in the listening room and connected to signal cables and mains power it can be switched on via the mains switch above the mains input socket on the rear panel.

The 18S must be configured appropriately for the audio system and main speakers with which it is to be used. This is achieved via the rotary controller, display and menu based interface on the rear panel. Turn the rotary controller to select configuration parameters and press the control to select options and save any changes.

General Tips

Check it out

Try different subwoofer positions and settings, before you finally choose a setup.

Note down settings

When looking for the best subwoofer position in the room, note down the ideal setting you found for a position. When moving the subwoofer between two positions you will be able to set the subwoofer to the same configuration as found before.

Vary the listening music

When experimenting to find the optimal settings, use a couple of music tracks with repetitive bass across a large spectrum. The tracks should be sufficiently different from each other and each should cover a wide bass-range.

Musical instruments, such as a double-bass, bass guitar, church organ, etc. covering a wide spectrum in the bass region and above, are very suitable as these depend on accurately balanced subwoofers and main speakers.

Verify changes

Although in general it is best to make adjustments in the sequence outlined below, note that changing one setting may influence another. For example, finding the right setting for phase may result in having to decrease gain, even if this was set correctly before.

It is recommended that you double-check the previous settings before moving on to the next one. Obtaining the best integration of the subwoofers generally involves a considerable amount of repeated fine-tuning.


If multiple subwoofers are employed, they should be configured as described in Installation.

18S Configuration Menus

Auto, ON/OFF

The Auto, ON/OFF switch enables auto standby (Auto) or forces the subwoofer to be permanently on (ON/OFF).

In Auto mode, the subwoofer can be “woken up” by

  • an audio input signal,
  • rotary knob push,
  • a trigger input if Trigger is enabled in the menu.

For more information, see the following sections.


Set to match the volume of your main speakers so that bass at your main listening position is neither too prominent or too quiet. Setting the subwoofer volume is important in terms of both overall system balance and the demands of different types of programme material.

Input sensitivity

Adjusts the input sensitivity to match the output level of your pre-amplifier or audio-visual processor.

Setting Input Sensitivity

The wide variety of possible source equipment types that can be connected to an active subwoofer means that it is important to set the input sensitivity appropriately. Doing so will help ensure that the subwoofer’s volume adjustment range is adequate and that its input and DSP electronics are driven properly.

If the source equipment has a published specification for output level, begin by setting the 18S input sensitivity to match the specification as shown in this table:

Source Output Level 18S Setting
<1.0 V +6 dB
<2.0 V 0 dB
<4.0 V -6 dB
<10 V -14 dB

The -14 dB sensitivity setting should generally be used when the 18S is used for the LFE channel in a home theatre system.

If the source equipment has no published output level specification, begin by setting the Input Sensitivity to -6 dB. If then when in use the 18S volume setting is required to be towards either its maximum or minimum values, adjust the Input Sensitivity appropriately such that the volume setting is towards the middle of its range.


The 18S incorporates low pass filter presets for a range of Dynaudio speaker models.

If your 18S is to be used in a system with one of the Dynaudio models listed, select it to automatically configure the 18S low pass filter appropriately.

If your Dynaudio speaker model is not listed among the 18S presets, or if your 18S is to be used with speakers from an alternative manufacturer, select a low pass filter frequency closest to the speaker’s specified -6 dB low frequency cut-off.

If your subwoofer is to be used for the LFE channel in a home theatre system select the filter Bypass option.


Matching the filter frequency of the subwoofer to the bass cut-off frequency of the main speakers will have an important impact on the overall system sound quality. In general, larger main speakers will have more extended bass so will require a lower subwoofer filter frequency. Conversely, smaller main speakers are likely to require a higher subwoofer filter frequency. If the subwoofer filter frequency is not set optimally, the overall frequency response of the system may display an audible peak or dip around the crossover frequency. The diagram opposite illustrates the three frequency response characteristics that might result from optimum and non-optimum subwoofer filter settings.

Subwoofer filter frequency set too low

  • L: Level
  • F: Frequency
  • Dark grey line: Main speakers
  • Light grey line: Subwoofer
  • Brown line: System response

A dip in the system response will occur if the filter frequency of the subwoofer is set too low – perhaps with small main speakers that do not have extended bass response. The result will be missing musical information and a thin overall sound.

Subwoofer filter frequency set too high

  • L: Level
  • F: Frequency
  • Dark grey line: Main speakers
  • Light grey line: Subwoofer
  • Brown line: System response

A peak in the response will occur if the filter frequency of the subwoofer is set too high – perhaps with large main speakers that have an extended bass response. The result will be an excess of mid-bass energy that will sound unnatural and bloated.

Subwoofer filter frequency set optimally

  • L: Level
  • F: Frequency
  • Dark grey line: Main speakers
  • Light grey line: Subwoofer
  • Brown line: System response

The subwoofer and main speakers are well matched. The system frequency response is smooth without a peak or dip. A well balanced sound will result.


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.

Parametric EQ (PEQ)

Provides three bands of low frequency parametric equalisation. Each band offers frequency, gain and Q parameters. The equalisation is set “flat” by default.

Using Parametric Equalisation

The digital signal processing power incorporated in 18S enables three bands of parametric equalisation to be applied to the input signal. Parametric equalisation can be viewed as finely targeted tone control that is able to correct specific frequency response anomalies caused by room acoustics.

It should only be used after the subwoofer position has been finalised.

Each band of parametric equalisation offers three control parameters: frequency, level and Q. “Frequency” defines the centre frequency around which the equalisation band operates, “level” defines the degree of boost or cut, and “Q” defines the width of the equalisation band (a higher Q means a narrower band). These control parameters are illustrated in the diagram opposite.

The 18S Parametric EQ is intended to be used in combination with professional room acoustic analysis to identify response anomalies, however the Dynaudio Sound Meter app (available free from the Apple app store) incorporates a real time frequency analyser that can be used to help identify anomaly frequencies and so guide parametric equalisation set up.

Sit in your main listening position, launch the Sound Meter app and select the RTA option while playing a “pink noise” signal through the subwoofer (pink noise can be found on many music streaming services). Prominent peaks in the response curve displayed by the app will most likely correspond with any audible frequency response anomalies. Equalisation bands can then be set at the anomaly frequencies and the level and Q parameters adjusted to flatten the response curve.

Further guidance on using subwoofer parametric equalisation can be found on the 18S product page at


The diagram shows one band of parametric equalisation set with a relatively high Q (approx 5) and approximately 6 dB of attenuation.

The Parametric EQ of the 18S is a powerful tool and it should be used carefully. In the vast majority of circumstances equalisation should be used to attenuate room anomalies rather than not to boost subwoofer bass. If more bass is required always try repositioning the subwoofer first.

Parametric EQ parameters

  • L: Level
  • F: Frequency
  • Q: Quality factor

HP Filter

Engages or disengages a 4th order, 80Hz Linkwitz-Riley high-pass filter on the Left/Right outputs. Engaging the high-pass filter ensures that low frequency signals below 80Hz are not passed to satellite speakers connected to the subwoofer outputs.

Auto standby

Select to specify the delay time before the subwoofer will switch to Standby mode when unused. The auto standby feature can also be switched off using the Auto On/Off switch on the backplate.

Trigger (5 - 12 VDC = on)

Select one of four options:

  • Disable: Trigger input is ignored.
  • ON/OFF: Trigger input is required to turn the 18S on.
  • Mute sub with High pass: Trigger input mutes the 18S with main speakers high passed.
  • Mute sub without High pass: Trigger input mute the 18s with out high pass filtering the main speakers.

Left main speaker distance

Select to specify the distance in centimetres of the left main speaker from the listening position.

Right main speaker distance

Select to specify the distance in centimetres of the right main speaker from the listening position.

Subwoofer distance

Select to specify the distance in centimetres of the subwoofer from the listening position.

Factory Reset

Select to return your 18S to its default settings.

Software version

Displays the installed firmware version.