Design

Design

Control module




The audio module (AUD) is an amplifier which is connected to the MOST network. It has the following functions:
- to carry the sound signal transmitted on the MOST network out to the directly connected loudspeakers
- to carry voice messages from the microphone, which is directly connected to the audio module (AUD), to the MOST network.
If a subwoofer module (SUB) is installed on the MOST network, the audio module (AUD) can process the incoming signal and transmit it to the subwoofer module (SUB).
There are three versions of the audio module (AUD):
- Performance (included after structure week 2004w46 in the Integrated Audio Module (IAM)). Has an output of 25W per audio channel. The control module has 4 audio channels, these produce a combined output of 100W.
- High Performance. Has an output of 40 W per channel. The control module has 4 channels, giving a total output of 160W
- Premium Sound (not C70). Has an output of 70W per channel plus an output of 25 W for the channel for the centrally-mounted speaker. The control module has four channels plus the channel for the centrally-mounted speaker. This gives a total output of 305W.
- Premium Sound (C70). Has an output of 130 W per channel. The control module has 5 channels, giving a total output of 650W.
Each version of the audio module (AUD) has a different number of loudspeakers and different loudspeaker models.
All versions of the audio module (AUD) have a microphone input. This is used by the phone module (PHM) for phone calls (hands-free) for example.

Functions in the audio module (AUD)
The audio module (AUD) can run a number of different functions, but these functions can also be activated by other nodes. An example of these functions is lowering and increasing the volume. The signal comes from the infotainment control module (ICM), but it is the audio module (AUD) that actually changes the volume. The functions are described below.

Functions in the audio module (AUD):
1. Adjustable volume, raises and lowers the volume
2. Adjustable bass, raises and lowers the bass level
3. Adjustable treble, raises and lowers the treble level
4. System generated sound signals, assists other nodes in the system with single sound signals generated in the control module, for example alarm signals for the back-up (reverse) warning function
5. Limiter, the limiter function in the control module does not permit an increase in the power output level if this leads to a fall in sound quality
6. Mixing, mixing allows numerous different sound types to be mixed. In this case, the different sound types are foreground noise, background noise and system generated sound signals. An example of this is where a CD is playing (background noise) and the carphone rings (foreground noise). The ringing signal will be heard through the loudspeakers while the volume of the music drops at the same time
7. Digital bass speaker output, the control module transmits sound signals to the bass speakers via the MOST network. The signal is processed in the audio module (AUD) before it is transmitted on the MOST network to the subwoofer module (SUB)
8. Bass compensation, the bass from the control module is compensated or modified depending on the volume level and the speed of the car. If the vehicle speed and volume level changes, the bass compensation is also changed
9. Treble compensation, the treble in the control module is compensated or modified depending on how the volume is changed. If the volume changes, the treble compensation also changes
10. Equalizer setting, sound compensation, there are different settings for the sound from the audio module (AUD). This compensates for factors such as the location of the loudspeakers and the layout of the car interior
11. Dolby ProLogic II, a surround decoder for sound reproduction.
There are two types of sound, foreground sound and background sound. The sounds which are foreground and background are listed below.

Foreground sound
- telephone calls
- carphone settings (setting the ring signal)
- navigation
- system generated sound from the audio module (AUD) (different types of alarm sound)
- traffic messages.

Background sound
- analog radio, AM/FM
- CD player
- MD player.
The functions in the different versions of the audio module (AUD) are:

Performance
1. adjustable volume
2. adjustable bass level
3. adjustable treble level
4. system generated sound signals
5. limiter.

High Performance
1. adjustable volume
2. adjustable bass level
3. adjustable treble level
4. system generated sound signals
5. limiter.
6. mixing
7. digital bass speaker output
8. bass compensation
9. treble compensation
10. equalizer.

Premium Sound
1. adjustable volume
2. adjustable bass level
3. adjustable treble level
4. system generated sound signals
5. limiter.
6. mixing
7. digital bass speaker output
8. bass compensation
9. treble compensation
10. equalizer.
11. DPL2 - Dolby ProLogic II.

Loudspeakers




All versions of the audio module (AUD) permit the installation of two pairs of loudspeakers:
- front loudspeakers in the front doors
- rear speakers in the rear doors. For C70, the rear speakers are in the side panels.
In some versions of the audio module (AUD), a treble speaker can be connected to the front and rear speakers. Premium Sound also contains a loudspeaker mounted centrally in the dashboard. Treble loudspeakers, when installed, are always installed in the upper parts of the doors. The three audio module (AUD) versions have different loudspeaker arrangements:

Performance
- one pair of front loudspeakers
- one pair of rear loudspeakers.
The loudspeakers are the broad range type and cover the whole frequency range. In England and USA there is also a smaller type of treble loudspeaker in the front doors.

High Performance
- one pair of front bass speakers with treble loudspeakers
- a rear pair of loudspeakers with treble speakers.
The front treble speakers are electrically connected to the same signal cable as the front loudspeakers. The rear treble speakers are electrically connected to the rear loudspeakers.

Premium Sound
- a front pair of 3-way loudspeakers consisting of a pair of 2-way loudspeakers (bass and mid range) with treble speakers
- a rear pair of loudspeakers with treble speakers
- a 2-way centrally mounted loudspeaker (available in two versions 1)) positioned in the dashboard.
The front treble speakers are electrically connected to the same signal cable as the front loudspeakers. The rear treble speakers are electrically connected to the rear loudspeakers.
1) When the display is installed in the dashboard the bass and mid range elements of the center loudspeaker are 31/2 inch, otherwise 5 inch.





2) When the display is installed in the dashboard the bass and mid range elements of the center loudspeaker are 31/2 inch, otherwise 5 inch.
3) In England and USA there is a smaller type of treble loudspeaker in the front doors.

Microphone




All versions of the audio module (AUD) have a microphone which is directly connected to the control module. The microphone is in the roof console.
The microphone is used for functions such as hands-free in the phone module (PHM).