Signal Processing Module: Description and Operation

Subwoofer Module (SUB)

System Overview

Control module

Subwoofer Module (SUB):

The primary task of the subwoofer module (SUB) is to manage sound reproduction from the audio module (AUD) to the subwoofers.

The subwoofer module (SUB) only functions if the audio module (AUD) is connected to the MOST network.

The Subwoofer module (SUB) checks activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored in certain cases if the control module detects a fault. Any diagnostic trouble codes (DTCs) are stored in the control module memory.

The subwoofer module (SUB) uses the MOST network to communicate with other control modules.

In order to function in the MOST network, the Infotainment control module (ICM) checks that the correct serial number is in the Subwoofer module (SUB). If the number is not correct, the Subwoofer module (SUB) will not function. If the problem persists when replacing the control module, try with the ignition on/off.

A simple way of checking if the Subwoofer module (SUB) functions is to activate the radio and then adjust the volume.
The sound from the Subwoofer module (SUB) should rise and fall as the control is adjusted.

NOTE: Ensure that the bass loudspeaker is selected in the infotainment control module (ICM).

The subwoofer module (SUB) is on the left-hand side in the cargo compartment.

Signals
The table below summarizes the input signals to and output signals from the Subwoofer module (SUB). The signal types are divided into directly connected signals and MOST communication. The illustration below displays the same information with the Volvo component designations.










Design

Control module







The Subwoofer module (SUB) contains an amplifier.
The amplifier has two channels, one for each voice coil. The output from each channel on the amplifier is 130 W at 4 Ohms.
Power booster amplification is set so that the acoustic output from the subwoofer module (SUB) matches the other speaker channels.

Subwoofer module (SUB) is 30 supplied.

Subwoofer







There are two subwoofers, these are installed behind the backrests.

The speaker elements are two 9 inch subwoofers with a voice coil in each. The impedance is 4 Ohms for each coil.

Function

Sound reproduction







During the transfer of sound signals to the Subwoofer module (SUB) (16/79), the Infotainment control module (ICM) (3/281) allocates a channel on the MOST network. The Audio module (AUD) (16/105) transmits sound signals to Subwoofer module (SUB) via the MOST network.
All filtering and sound treatment of the sound signal occurs in the Audio module (AUD).
Volume control occurs in the Subwoofer module (SUB).

The volume of the subwoofer module (SUB) is raised or lowered using the volume knob on the infotainment control module (ICM). The infotainment control module (ICM) transmits a request on the MOST network to the subwoofer module (SUB), which then processes the request and actively raises or lowers the volume.

The limiter function in the subwoofer module (SUB) does not permit an increase in the output level if this would lead to a reduction in sound quality.