SurroundTraxx: How It Works

SurroundTraxx stores a roster of locomotive sound settings in a database called the Roundhouse. This is an extensive library that you can set up and adjust to closely match your model's prototype or to sound like your favorite horn, prime mover, exhaust chuff or whistle. Each engine can sound completely unique!

Once you have entered your locomotive roster into the Roundhouse your SurroundTraxx system has an internal “dispatcher” that allows up to 6 trains to be in operation at one time. SurroundTraxx can be set up to pick the first 6 locomotives detected or you can assign these slots to locomotive of your choice (Perfect to make sure your favorite engine never goes silent!). These locomotive “slots” used by the dispatcher are called Auto Dispatch slots (AD slots).

Once the trains have been dispatched, the block detector will identify the trains' location, at what speed they are traveling and at what point they cross into new blocks. SurroundTraxx uses this information to move the appropriate sounds to the appropriate sound channel (out of six available) on the SurroundTraxx unit. Additionally, SurroundTraxx uses an intelligent cross fade algorithm that factors in train speed, direction, and distance between speakers and reproduces the sound in such a way that it appears as though the sound is coming directly from the train and not the speakers on the layout.

The multiple trains running on the layout can all be in the same area or spread throughout the layout. SurroundTraxx will still dispatch and reproduce their respective sounds in full audio richness. It truly is a complete layout sound system with multiple trains and operating sessions in mind!

Note: If using single channel mode (default) then the sound simply goes through all 6 channels and doesn’t follow the train. In order to set up the other modes of operation you must be using Digitrax® transponding® block detection on your layout for proper operation.

Feature Highlights Found in SurroundTraxx

  • Six Sound channels which allows for up to 6 different ‘sound zones’ on your layout

  • Simultaneous sound operations for up to 6 trains to be dispatched at once

  • Roundhouse memory storage for up to 99 locomotives in the database

  • An extensive sound library to closely match your prototype locomotive

  • Adjustable ambient effects such as echo and reverb

    SurroundTraxx includes the following items:

  • SurroundTraxx system

  • 5 Volt Power Supply

  • Network cable

  • Speaker harness for 6 sound channel outputs (6’ sections of each)

  • Quick Start Guide

  • Owner’s manual CD

  • Customer Registration card

    Additional Items Needed for Operation


  • Up to six 8-ohm speakers

  • Optional Subwoofer

  • The appropriate DCC mobile decoders equipped with transponding or a TL-1 transponder

  • Digitrax DCC Command Station, cabs and power boosters

  • Additional Speaker wire if using a distance greater than 6’

  • Digitrax BDL-168 (or older BDL-162) Block Detectors

  • Digitrax RX-4s (8 total)

    • Speakers


    SurroundTraxx can accommodate up to 6 speakers per system, or 5 speakers and a subwoofer. The size and quality of these speakers are largely up to you and should be based on your layout design and the needs you identify in the planning process. However, we have a few helpful guidelines and some requirements to help you get the best audio experience.

    The speakers you choose must be passive 8-ohm speakers rated between 5 and 25 Watts. We recommend choosing speakers with a frequency response of at least 80 to 16,000 Hz. If you plan to use a subwoofer, you may use smaller speakers with a frequency response of 150 to 16,000 Hz, as the subwoofer will provide the bass.

    Mobile Decoders and Transponders


    SurroundTraxx is a sound system designed to operate on DCC layouts. In order to operate SurroundTraxx in transponding mode (multiple trains in multiple sound zones) you must have DCC mobile decoders with transponding installed in your locomotives. Alternatively, you may add separate transponders to any DCC mobile decoder that you may already have installed. To emphasize this point, when utilizing SurroundTraxx to its full capabilities, you must either use decoders that come equipped with Digitrax transponding or purchase a TL-1 transponder to add to the locomotive. Sound decoders can also be installed in the locomotive but are not required. Locomotives that aren’t equipped with transponders will still run on the layout but will not be able to be dispatched or produce any sound through your SurroundTraxx system.

    DCC Command Station, Cabs and Boosters


    SurroundTraxx requires a Digitrax LocoNet-equipped command station in order to operate in any of its different modes of operation. At this time SurroundTraxx cannot be used with other systems.

    Additional Speaker Wire


    SurroundTraxx comes with 6’ sections of speaker wire for each sound channel output. If your layout requires more wire you can add your own wire to the end of the wire harness included with your SurroundTraxx unit.

    BDL-168 Block Detectors


    To achieve the effect of sound traveling through your layout as your train traverses your layout, you must use Digitrax bi-directional block detectors known as BDL-168s. One BDL-168 will operate eight different blocks. Therefore, if your layout has more than eight blocks on your layout, you will need more than one BDL-168.

    Digitrax RX-4s


    Digitrax RX-4s are required in conjunction with BDL-168s and you must have one for each block on your layout. If you have ten blocks you will need ten RX-4s for your layout.