1185 - MMCT Sound/Comm

Speaker Mapping

In order to map the outputs of the MMCT aural cue system to a generic sound card, it must be defined in the C130Sound.cfg file. The config file should contain a section that looks similar to the one shown below, specifically, the "SpeakerMap" parameter.

[Audio]

Output=[default]

SpeakerMap=00h

SampleRate=44100

SpeakerMap is a hexadecimal value that is a combination of bits that are defined as the speaker positions. The following page from Microsoft's website describes the way this parameter works:

Channel Mask Description

This page provides an extended table of valid bit values (refer to the dwChannelMask definition):

dwChannelMask Details

On the MMCT, the output channel layout is:

1 - Front Left

2 - Front Right

3 - Rear Left

4 - Rear Right

5 - Sub-woofer

6 - Seat Shaker

The goal of the SpeakerMap parameter is to describe how that channel layout should be presented to the sound card. It may be possible to simply map the outputs straight through (SpeakerMap=03Fh). With that setting, the outputs will be mapped as follows:

MMCT channel --> Sound Card Output

Front Left --> Front Left (01h)

Front Right --> Front Right (02h)

Rear Left --> Front Center (04h)

Rear Right --> Low Frequency (08h)

Sub-woofer --> Back Left (10h)

Seat Shaker --> Back Right (20h)

Another example would be a SpeakerMap=0933h would be mapped as:

MMCT channel --> Sound Card Output

Front Left --> Front Left (001h)

Front Right --> Front Right (002h)

Rear Left --> Back Left (010h)

Rear Right --> Back Right (020h)

Sub-woofer --> Back Center (100h)

Seat Shaker --> Top Center (800h)

The MMCT channels must always be kept in the same order and once you have mapped a channel, the next channel mapped must be a greater value than the previous (once you have mapped an output you cannot go backwards in the table to map the next channel).

Some trial and error may be necessary to find the correct mapping to a specific sound card.