Stationary sound decoder for micro layout

[Kentuckian]

I’m getting back to my micro layout. It’s wired for both DC and DCC but I plan on doing most of the operations in DCC. I have at least half a dozen locomotives that could run on the layout. Some of these I plan to use on the big layout, whenever that happens, but a few of them are for the micro layout only. These locomotives are steam, diesel, and electric. I am an equal opportunity employer.

The layout is so small that I believe a stationary sound decoder would work. I don’t really need engine sounds, I only want three sounds: whistle, horn, and bell. Steam chuff for when I run the steamer would be cool but not a requirement at first.

My ideal scenario is to have ESU Lokpilots in the engines and one stationary sound decoder for at least whistle, horn, and bell. Is this possible? What’s the best way to accomplish this? I only plan on running one locomotive at a time. I have no experience with stationary decoders.

[peteski]

I don't think anybody makes a dedicated stationary sound decoder for the functions you would like to have.  ESU does not. But any mobile sound decoder can become stationary when  it is not installed in a locomotive. 
For initial programming purposes (on the programming track), you will have temporarily connect a spare motor, or you can just connect a 180 ohm 1W resistor instead of the motor.  The program it with whatever settings are needed.  Its address will have to match the mobile locomotive's address. You will have to turn the volume or the prime mover and all the other sound effects down to zero, but leave horn and bell volumes alone. 

Then disconnect the motor or resistor, add a speaker, and mount it in the station. Connect the track wires to the track and you're good to go.  That decoder will not care that it is sitting at the station.  It will play the horn and bell just as if it was installed in a loco. You might also have to adjust the master volume, but that can be done by programming the CVs on main (while the loco using the same address is removed from the layout).

The only complication is choosing between a diesel horn and steam whistle.   I suppose if you have the capability, you can configure the sound project to have both sounds, then map peach one to a different function.  For example Bell would be F1, horn F2 and whistle F3.  If you want to go all the way, you could also custom install other ambient sounds to that decoder and trigger them using other function keys.

Or for another idea, Soundtraxx sells sound only decoders for train sound effect.  My friend has couple of them installed in Kato passenger cars of his UP executive train.    The can produce sounds like squeals or clicks.  They add another dimension to the sound effect of the moving train.   Those can also be installed in stationary application.  See https://soundtraxx.com/products/tsunami-soundcar . They are also less expensive than a typical  mobile sound decoder.  Actually that is probably a better choice than using a mobile sound decoder.  Just address it using the same address as the locomotive being ran.

[Kentuckian]

Thanks, @peteski!

[ednadolski]

It's up to you of course, tho I just would offer that having the engine sounds adds a lot to the effect. So much so, that when I shut everything off at the end of a session, it almost seems like the world has just gone to sleep.   

These are HO, but I do the same thing for N scale;

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These vids were mic'd 'live', that is, they were picking up the actual sounds that you hear (as opposed to adding sounds to the video).

What I do to hook up the stationary decoder is to connect the speaker output of the decoder to an audio output transformer, and the other side of the transformer to the input side of the under-the-layout speaker system.  It's important to lower the volume of the decoder to a pretty low level, to keep the signal from clipping (distorting).

For this use case, the mobile and stationary decoders are identical, with identical sound files.  All sound channels in the stationary decoder are turned off except for the prime mover.

I also recommend keeping the overall volume pretty low, it's not hard for it to get to be overpowering.

You can't see it in the videos, but running this with a ProtoThrottle is a trip

Ed

[peteski]

Doesn't the stationary decoder need a motor hooked up to properly play the different diesel notches which depend on the motor speed?  How about steam chuff synchronization?

[ednadolski]

Doesn't the stationary decoder need a motor hooked up to properly play the different diesel notches which depend on the motor speed?

I've never used one.  AFAICT it's open-loop, just driven by the software in each decoder's cpu, and they seem to stay in sync pretty well.  But perhaps it's different with other brands or older decoders.   Anyways it would not be hard to add one, if ever it turns out to be needed (e.g. for steam).

Curious... what CPU does Loksound use?  Perhaps ARM-based?

Ed

[peteski]

I've never used one.  AFAICT it's open-loop, just driven by the software in each decoder's cpu, and they seem to stay in sync pretty well.  But perhaps it's different with other brands or older decoders.   Anyways it would not be hard to add one, if ever it turns out to be needed (e.g. for steam).

Curious... what CPU does Loksound use?  Perhaps ARM-based?

Ed

ESU uses Atmel made microcontrollers and  while I don't have one handy now, I believe the newest decoders do use ARM-based processors.

Yes, the firmware design does vary quite a bit between decoders.  The the virtual-cam chuff sync is usually based on the BEMF generated by the motor, so no motor and chuffs will be way off, or no chuff at all.  It might not be as critical for diesel motor decoders.