SurroundTraxx: Planning The Layout

The SurroundTraxx User's Guide will guide you through the planning and installation process, from the initial planning stages to final system configuration.

Installation involves these major steps:

  • Plan your layout
  • Define your track plan
  • Create a schematic
  • Divide and wire your layout into blocks
  • Define your sound zones
  • Identify speaker locations
  • Verify the detection is working

Plan Your Layout

By the time you begin planning for sound, you’ve probably already given a lot of thought to the other elements of your layout. Naturally, the extent of planning required varies by the complexity of the layout and its stage of completion when you begin installation of SurroundTraxx. We encourage you to enjoy the planning stages, taking time to consider the multiple factors in play.

If you are adding SurroundTraxx to a layout that is otherwise complete, you may find it helpful to take a test drive in transponder-free mode before finalizing the sound zones.

When deciding how to wire your layout the first factor is choosing which operating mode you would like to implement on your layout. This may change the set up and wiring of your layout. For instance if you wish to use SurroundTraxx in Transponder-free mode then you will wire the layout just as you would for any basic DCC layout. In other words, you wouldn’t need to divide the layout into blocks or add any of the transponding equipment offered by Digitrax. If, on the other hand you wish to use either 6-channel or 5-channel with a subwoofer mode, you will need to take into account two factors in the general wiring of your layout. The first of these factors is how many block detectors you need, and the second is how many sound zones you plan on having.

The table below lists some general size guidelines for a sound zone on your layout. As a reminder a sound zone and a block are not the same thing as a sound zone can encompass multiple blocks within one sound zone. If you intend to use single channel mode you can disregard this table, as the entire layout would be one sound zone.

Layout Size Sound Zone Size
Tabletop Layouts (4’x8’) 2’ to 3’ between speakers
Small Layouts4’ between speakers
Medium Layouts6’ between speakers
Large Layouts 8’ between speakers

Define Your Track Plan

If you are adding SurroundTraxx to an existing layout, you likely already have a track plan in one form or another. Otherwise, the track plan is your first opportunity to begin planning for sound. The track plan is a scale drawing of your layout, reflecting its geographical realities: each curve, loop, straightaway, etc. It is a helpful tool in identifying challenges and potential tricky spots such as reverse loops and wyes.

The User's Guide shows an example layout to help illustrate the principles employed when planning for SurroundTraxx installation.

Create A Schematic

For the purpose of SurroundTraxx setup, a detailed electrical schematic is not required, but a basic schematic is an important step in separating the layout into blocks, which is a prerequisite to defining your sound zones.

Divide and wire your layout into Blocks

The schematic will help you assess the factors that affect the block divisions. For example, you wouldn’t want to place a block boundary in the middle of a siding. Instead, the boundary should occur at one end of the siding or the other. Likewise, a wye or yard should usually be confined to a single block. Even if you’re not using block detection with signaling devices, it’s helpful to plan your blocks as if signaling were part of the picture.

Define Your Sound Zones

A sound zone is the area covered by one speaker. You’ll want to revisit your track plan and schematic with the determined the block boundaries, as these resources together are a great help in defining the sound zones. Remember that the sound zones you define for SurroundTraxx relate to, but don’t necessarily equate to, the detection blocks. In other words multiple blocks can be in one sound zone. Each SurroundTraxx unit supports up to six sound zones.

Identify Speaker Locations

Ideally, speakers should be placed as close to the center of your sound zones as possible, as seen in the example below. You may also want to consider the speaker's shape and size when deciding on speaker placement. Some speakers are easier to conceal than others, and this should be a consideration as you shop for speakers.

Ideally, the subwoofer should be mounted under the benchwork or on the floor. This provides optimal low-frequency response without causing vibration within the benchwork and scenery.



When installing speakers you can conceal them in the benchwork, inside larger buildings or building facades, or behind greenery. You could also mount them in your ceiling or wall. If your layout incorporates mountainous terrain, you can build speaker compartments into hillsides. Wherever you decide to conceal the speakers, plan for easy access later in case of a loose speaker wire, failed speaker, or another maintenance issue. Self-amplified speakers will have onboard volume controls and possibly other controls, so be sure you can access them.