SoundTraxx has been providing Tsunami Digital Sound Decoders to Bachmann Trains since 2006. If you have purchased a quality Bachmann® Spectrum® locomotive equipped with SoundTraxx Tsunami Digital Sound Technology, congratulations! This state-of-the-art sound decoder will provide all the pleasures of high-quality, digital onboard sound and the benefits of DCC technology. If you aren’t sure, look for the "DCC Sound On Board" logo on your locomotive’s box.
Beginning in late 2011, Bachmann Spectrum locomotives that are ordered with DCC come equipped with a SoundTraxx Mobile Decoder that has a 21-pin plug and a speaker already installed. Bachmann also sells a separate sound module to plug into the 21-pin connector. The sound module and the mobile decoder plugged in together act the same as the Tsunami found in the 2009-2010 released Spectrum models.