Changing Sounds on Digitrax Sound Decoder – Part 1

In October last year I showed you how I fitted a Digitrax DCC sound decoder and speaker into the tender of an N scale steam locomotive, you can read the post here.  At the end of the post I mentioned that when the locomotive was put on the track and powered up, diesel sounds played instead of steam.  In this post I’ll show you how this can be changed.

As standard, Digitrax sound decoders come with pre-installed sounds, normally for generic diesel and steam locomotives.  These are also for US outline locomotives so they may not be ideal if you model trains from other countries, but as a generic they’re not too bad.

There’s a simple way to change the generic sounds and adjust the volumes. And there is a slightly more complex method which allows you to totally change the sounds, which then enables you to use them for other countries too.

The first and simplest method is to switch between the diesel and steam sounds and, for many, this is sufficient.  This is done by altering the value of a certain Configuration Variable or CV.  CVs are the electronic switches within the DCC decoder which control all the options such as the locomotive’s address, light functions, maximum speed and sounds.  The majority of DCC controllers or command stations have the ability to read and changes these CVs.

I won’t be able to give you instructions on how to change the CVs on your particular DCC controller as there are so many different makes and models, and they’re all a bit different. However you should be able to find out how to do it from your operator’s manual; it’s normally under the decoder programming section.  The good thing is the principle is basically the same for all.

Normally this involves placing your locomotive onto a programming track.  This is a section of track which is totally isolated from the rest of the layout and only connected to the programming track output on your DCC controller or command station.  Why do this?  Well, if you programmed through the main track feed it will talk to all of your trains at the same time. Also the programming track has a much lower power output, so if something is wrong it shouldn’t damage the decoder.  There are ways to program specific locomotives on the layout by ‘programing on the main’ but I’ll discuss that at a later date.

With your locomotive on your programing track, ask your DCC controller to read CV60.  This is the switch which tells the sound processor which sound set to use. If CV60 = 0 then it will use the steam set, if CV60 = 1 then it will use the diesel set.

So if you’ve installed the sound decoder in a steam locomotive and CV60 = 1, follow the instructions for you DCC controller to write or change CV60 to 0.  Then, when you put the locomotive on to the main track, it will play the steam sound set.

Using this basic method of altering CVs you can also alter other sound related functions. CV58, for example, is the master volume.  As standard it’s set to 9 but can be increased to 15 if required.

Below is an extract from a Digitrax Sound Decoder manual showing some of the CVs which can be adjusted.  I would recommend being methodical when doing this as changing the wrong CV can cause the decoder to behave in a strange way. In the event that it all goes wrong and you don’t know what you did, don’t panic!  There is a simple way to reset the decoder back to factory settings.  This is done by setting CV8 to 8.  Please note that not only will this reset volumes and sounds to the diesel set but it will also reset your locomotive number to 03.  This is is definitely something only for the programming track.


I like to increase the master volume as well as the whistle and prime mover/steam chuff sounds but leave the bell turned down.  I find the bell a bit annoying!

One thing to consider, if you set the volumes so they’re just right for you at home, where it’s probably fairly quiet, you may find if you take your trains to exhibitions or club nights the sounds may get drowned out by the background noise.

But what if you don’t want your locomotive to sound like a generic US steam engine; what if it’s a British LNER A4 or German Ice HST?  Well, that can be changed too using the slightly more complex method I spoke about earlier and in next week’s post I will show how to do it, step by step.