ESU LokSound AutoTune

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See the Video.


The ESU LokSound 5 / LokSound 5 DCC multi-function sound decoder has a feature called Auto Tune. Some older LokSound V4.0 decoders may also support this feature. Auto Tune allows for automatic calibration of the motor control parameters, such as the BEMF, without editing CVs. It can complete this task more accurately than manually attempting to set the appropriate CVs.

Read your manuals to determine if the feature exists in other decoders by ESU, such as the LokSound 4. This feature may be absent from economy OEM versions.

Auto Tune

The LokSound 5 software controlling the motor operation has been further refined. The Pulse Width Modulation frequency ranges from 10 to 50 kHz for silent operation, with a benefit particularly for coreless motors.

The Load Control has 10 CVs to tune it. The Auto Tune feature allows all ten to be adjusted by the decoder software, perfectly matching the motor performance.

How Does the LokSound Auto Tune Work?

Before beginning, reading and recording the contents of CVs 51 to 56 is advised. This is easiest with the LokProgrammer, or using JMRI's DecoderPro.

For best results, the locomotive should have some running time on the mechanism. A locomotive with a broken in drivetrain will perform better. Run the locomotive for a few minutes before bringing it into position on the track section to be used.

Running Auto Tune

For effective calibration, a length of straight track at least 1.3m long is recommended.

  • Set CV 54 to the value of 0 (zero)
  • Leave programming mode
  • Press F1
  • The locomotive should begin travelling down the track: It will launch at full speed in the last direction of travel, so ensure it will go the right direction before beginning the process.
    • At the completion of the Auto Tune process, the locomotive will stop and ring the bell. This should be completed within 1 metre of travel.
    • Press F1 to silence the bell.


After the Auto Tune process has completed, verify operation by taking the locomotive on a test run. If further adjustment is needed, set CV53 to a value of 120, and increment or decrement that value as needed.

Known Problems

Some locomotives with factory (OEM) multifunction decoders installed may not work correctly with AutoTune. Rapido Trains' RDC and Royal Hudson may not tune correctly due to their custom programming.

Royal Hudson by Rapido

These locomotives and their ESU Multifunction Decoders require a different reset procedure as setting CV8 to "8" will not change the necessary CVs on the ESU LokSound Version 5 decoder. To reset this model to its original factory settings, follow this two-step procedure:

Step 1

  • Select the locomotive address you are currently using. If you did not program a custom address, the default is "3".
  • In programming mode, change CV8 = 8
  • Cycle power. This may require leaving programming mode and energizing the decoder, then disconnecting power or removing the locomotive from the track.

Step 2

  • Select address "3"
  • Change the values of these CVs in the order listed below:
  1. CV51 = 1
  2. CV52 = 0
  3. CV53 = 120
  4. CV54 = 50
  5. CV55 = 100
  • Cycle power.

Your model is now reset to factory defaults and will respond to address "3" until a custom address has been programmed.

  1. Changes can be made with most DCC systems, an ESU LokProgrammer or JMRI.
  2. Some DCC systems may not provide adequate current to reprogram an ESU decoder. If this happens, you will need to use a DCC Programming Booster.
  3. Use caution during programming, make sure it is isolated and that no other locomotives sharing the same address are active.

ESU Tech Tip

Short video demonstration of AutoTune.

Further Reading