I have a lot of locomotives on the Tam Valley with sound chips in them and now that the novelty of having a locomotive that can go "whoo-whoo" has worn off, I have become somewhat dissatisfied with the sound quality. Now don't get me wrong - I am sure the sound samples in the chips are very good and they are amazingly well synchronized to the engine movements - it is that tiny little speaker that is the fundamental problem. You just can't get great sound out of a sub 1" inch speaker. Especially missing is the deep bass rumble of the diesels that is so striking when you hear a 1:1 scale diesel go by. The engine that has the sound I am most satisfied with is my cab-forward. Steam engines are more about hiss and chuff, which is mostly higher in frequency and there is room for a larger speaker with a bigger sound chamber in the tender. For the new layout I wanted to address this issue by building a sound system into the layout from the very beginning. The sound system will track the movement of the train around by altering the volume on an array of speakers. Soundtraxx announced such a system recently which I saw demo'd at the National Train Show in July. I looked more into how to install it and found several things that were a bit inhibiting. For one, it only works with Digitrax as it relies on Loconet and on Digitrax block detection. The block detection needs to be able to identify not just that the block is occupied but which engine(s). This requires changing all the decoders to ones that can send their ID back. The system will be quite complex to set up. The big advantage is that once set up, it will produce much better sound than having tinny little speakers in each engine.
However, I have decided that this would be a really fun project for me. I have built my own audio systems in the past and have a lot of experience in electronics and computer control of systems. So I thought I would try to build a system of my own design! I have some novel ideas on how to implement this. My design goals are to have a system that is easy to run once it is up (although it doesn't have to be easy to build or program initially) so that visitors can just run trains and have the sound work. It will use speakers mounted behind the layout and have a nice big sub woofer to rattle the floor when a diesel starts up. It should annoy my neighbors in proportion to their 3 barking dogs (please no one tell them about this criteria :-). It will follow the engines around by manipulating the volume in the sound channels.
First off is how to generate the sounds. I have read about people using sound cards with the same CV as the engine connected directly to a speaker under the layout. It is especially useful for a yard or switching area where the engine goes back and forth in a single area. I tried this out by taking a spare Soundtraxx decoder I have and hooking it up with alligator clips to the track and jury rigging a connection to one of my stereo speakers. Wow - big improvement in sound! It responded nicely to the throttle without being hooked up to a motor. The bell and whistle worked fine.
I was particularly keen to see the new Digitrax sound bugs released. These chips have just the sound functions on them and are fully programmable for a variety of engines. You can prepare one of these through a USB connection to your computer with downloadable sound files. As Digitrax states in their product info, these make great standalone sound chips. Ideally, I don't want to have to modify any of my engines by opening them up on the workbench and soldering tiny little wires or trying to find space in already crowded mechanism.
So I envision a system where a number of soundbugs are connected underneath the layout to the sound system. Each soundbug gets programmed to an identical CV as an engine. As the train moves the sound will be directed to follow it as it goes. All of this is straightforward except for how to follow the train. I have an interesting novel idea for this that I will get to in an upcoming column. As a fallback the Digitrax system can work although this would mean replacing all my decoders.
Donner Summit Progress
I have put in the bench work for part of the staging basement and some of the supports for the upper level. This has let me get a sense of how the different levels will work prior to committing to their heights. i think it will work nicely. The aisles are going to be nice and roomy and there is lot of storage underneath. I am building in shelves as I go. I am going to have move the lights around to put them above the aisles. My plan is to have the room lights be separate from the layout lighting. To light the staging basement I am going to use super bright LEDs as they need only half of an inch in thickness. I am curious also to see if LEDs have gotten bright enough for lighting the rest of the layout. I suspect not from the specs. They still seem to need an order of magnitude in lumens to get close to fluorescents.
I have begun putting in the upper level supports along the wall. They will be 2x4's attached to the metal framing of the shed top and bottom. From that I will attach metal shelving brackets to hold the upper levels. The brackets will hidden behind the backdrop hardboard.I will post some pictures when I get there.