KB715: Customizing SoundFX Decoders

This article was last updated on July 20, 2011, 7:35 p.m. | Print Article | Leave Feedback

Digitrax SoundFX lets you make your locos sound like the real thing!

Remember, your Digitrax SoundFX decoder is ready to run and will operate and generate sound using address 03 with no additional programming.


On your Digitrax system, simply select the locomotive's address and the sound will start. On some DCC systems, it is necessary to select the locomotive address AND send a command to start the sounds. When used in conjunction with a separate DCC motor decoder in a single locomotive it is most practical to program both decoders to the same address and operating modes.

For a more prototypical railroading experience, your decoder can be customized for your specific locomotive by programming some of the Configuration Variables, or CVs, available. Digitrax Sound decoders can be programmed using either the direct mode on a programming track or with the operations (or OPS) mode on the main line.

Initial Test and Programming:

Digitrax decoders are preprogrammed and tested at the factory with one or more pre-installed locomotive sound scheme(s), and are ready to operate on factory default address 03. Before customizing your decoder you should first run it on the factory default address 03 without changing any CV values to check the installation and operation of the decoder.

Sound CVs & What They Can Do For Your Sound Decoders:

Sound CVs are in the range of CV140 to CV256.  This is above the mobile decoder motor and function CV range of CV01 to CV120.   

CV58=Master Volume Control

CV60=00 or 01 to select an alternate scheme, if provided in the decoder

CV155=Diesel engine notching modes.
CV155=00 provides automatic notching that changes the diesel RPM settings at 8 distinct throttle speeds that are controlled by CV132
CV155=01 selects semi-automatic notching mode that allows F6 ON to increase the notch from the current throttle setting and F7 ON to decrease back towards the lowest current throttle notch setting
CV155=02 selects manual notching mode that allows F6 ON to increase the notch setting and F7 ON to decrease the notch setting irrespective of the throttle setting, which controls just the motor speed.

The decoder's sound scheme can be reloaded using a Digitrax PR3 or PR2 programmer and a sound project file (.spj) from the Digitrax Sound Depot on our web site. Typical sound downloads take between 50 and 100 seconds depending on the project complexity and file size.

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