DCC Sound

on the Sodumb & Gamorra lumber Co.

last updated: march, 3

Sound is relatively new to DCC. It brings a new dimension to our hobby one can easy to get adicted to. Soundsystems are common in the USA where conventional, non DCC based, units are used for some decades now. Even now these systems from PFM, PBL and others outperform the new DCC sound decoders in sound and functionality, using full range digitized and taped sounds. There is only one drawback: It is dead end street technology! Eventually digitized sound will get better. I believe that whitin 5 years from now sound will be common in decoders and at least one can choose between sound or non-sound equipped locomotives! All with DCC capability of course.

You have to be heard!

Bigger is better counts also for DCC sound systems. The delimiter is the space in the locomotive to hide a sound/motor decoder and speaker. H0 is a problem area here, not to mention N and Z scale. Scale 0 and upward is the arena for sound equipped locomotives. On our H0 S&G the only loco that has enough space to hide a decoder and a small speaker is the Bachmann Shay. The Heisler has no space left. And the tiny railcar I am building has only space for a scale N Lenz decoder. But for us there is another problem!

Performing on a model railroad exhibition with built-in speakers is like a live concert in a football stadium with an acoustic guitar and no microphone. Nice try. That is why we decided to install the sound decoders outside the locomotive. To do so we use Soundtraxx DSX decoders. The DSX is a dedicated sound decoder. But there is also some disadvantage: You cannot use the exhaust cam function. This means that there will be a (minor) problem with the synchonisation.

Wiring

The general idea is to give both the loco and sound decoder the same addres. From this point it is straight forward but be carefull; the DSX's output signal is strong and will blow up your amplifiers line-in without a pot-meter (variable resistor) between decoder and amplifier. Two or more sound decoders connected to one line-in will cause also trouble. This is my solution:

Instead of a resistor I use a simple sound mixer (TEC100). Every decoder can have its own channel and fader. In this way I can even mix environmental sounds (birds, industrial noise, ..) on a seperate channel with the exhaust of locomotives! Imagine a complex sound mixer with soundscapes, echo and even doppler!

Locating loudspeakers

Our loudspeakers are placed right behind the facia. The sound is directed into the layout and bounced back by the backdrop. In this way sound is filtered by the trees just as in real life.

Next:

• programming Soundtraxx DSX decoders (scheduled for april)
• Photo's of our soundsystem