A while ago there was some discussion on the LokSound forum concerning the Grade Crossing Signal and it being missing from the sound selections of the various LokSound decoders. The main reason ESU did not provide one, in their reasoning, was that the signal would always sound the same and the author agrees with this. There should be variation everytime this signal is sounded. It depends on the engineer.
Before we start this discussion you have to again realize that you cannot do what we are going to do with a Select decoder. You have no access to sounds schedules.
This was solved (ingeniously) by forum
member George Hofmann (Hello George!) with his sound schedule of this horn
signal.
It has a little bit of variability and also allows prolonging the final horn
blast which is controlled by the operator. It's built utilizing the Leslie RS3L
horn so a user will have to replace those sound segments with the ones from the
horn his engine is using.
In addition, this sound slot file uses a semi-documented
function in sound schedules called RANDOM.
The random function appears as rand(x,y) where x is the lower value and y is
the upper value. A better explanation is an example: u3 = rand(1, 4) assigns
either 1, 2, 3 or 4 to u3. This variable (u3) can be manipulated in various
ways as you will see shortly.
The main loop is shown in fig 1. The user registers 1 through
3 are used as follows: user 2 counts from 1 to 4 corresponding to the 4 horn
blasts. The rand function is used with user 1 to vary the 3 long horn blast
lengths and the silence in between them. The rand function is used with user 3
to produce an occasionally shorter short horn blast. Releasing the horn
function key allows the horn sequence to complete automatically. Keeping the
function on will hold the last horn blast until it is released.
Figure
2 shows the internal workings of the Loop container shown in figure 1.
This is where the various horn blasts are sounded and the lengths of the blasts
are controlled by the various user variables.
The
author could go step-by-step through the logic of these loops and he is sure
that your eyes will start glazing over after about 15 seconds and you will wake
up a few minutes later. The best way to
learn the logic is to load this file into the simulator and play it until you understand
what is going on.
This sound file is available for download here. You can then incorporate it into your projects through the templates import that I have discussed in previous posts. You will have to, of course, substitute the horn sound files of your choice. Which is simple drag-and-drop as demonstrated here.
This is an outstanding example of how to make use of the user variables and the random function. Hopefully
you will learn quite a lot.
If you have an idea for a blog post here, let me know. If I can comment on it, I will or I'll see if someone else can and post it
