SoundTraxx DSD-150/DSX Owners Manual - Manual (Page 28)

28 Digital Sound Decoder Owner's Manual
For Rule 17 Operation the headlight is mapped to both FL(fwd and FL(rev) by setting both CV 33 and 34 to 1 (0x01).
The backup light is remapped to a different function by setting the corresponding function map CV to 2 (0x02). For
this example, let’s use F1. If CV 35 is programmed to 2, your controller’s FL key would now control the headlight (in
both directions) and the F1 key controls the backup light.
Configuring the Sound Effects
The DSD provides five CVs for customizing the sound effects:
CV 50, Volume Control
CV 51, Background Sound Configuration
CV 52, Foreground Sound Configuration
CV 54, Auto Exhaust Rate
CV 55, Exhaust Tone
CV 56, Exhaust Volume
Setting the Volume
CV 50 may be programmed with any value between 0 and 15 (0x0F) to control the overall volume of the locomotive’s
sound. A setting of 0 will turn the sound off and a setting of 15 will provide maximum volume.
Setting the Exhaust
CV 54 is used to set the automatic synchronization rate or cutoff rate if cam synchronization is used.
For Auto-Exhaust synchronization, the chuff rate will be generated in proportion to the throttle setting. To select Auto-
Exhaust mode, CV 54 is loaded with any value between 0 and 255 (0xFF). Higher values will yield higher chuff rates
for a given throttle setting. The correct synchronization rate may be computed as:
SPD
CV Value = 115.9 X ------ X Gear Ratio
DIA
Where SPD is the locomotive’s top speed in scale miles-per-hour at full throttle and DIA is the locomotive’s driver
wheel diameter in scale inches, and Gear Ratio is the gear ratio for shays and other geared engines. For conven-
tional steam engines, use gear ratio =1. The driver diameter can be easily measured with a scale ruler but remember
to convert the measurement to scale inches.
If you don’t know your locomotive’s top speed, you can figure it out by using a stop watch to measure the time (in
seconds) it takes for the engine to travel over a 1/4 scale mile of track and using the formula:
900
MPH = -------
Time
Note: A 1/4 mile in N = 8' 3"
A 1/4 mile in HO = 15' 2"
A 1/4 mile in O = 27' 5"
For HO, a 1/4 mile is 15 feet, 2". If an engine take 20 seconds to traverse this distance, its speed is 45 MPH.
You can also estimate your locomotive’s top speed and still get pretty good results. A good rule of thumb is to use 45
MPH for freight locomotives and 70 MPH for passenger engines.
If you are using the exhaust cam, use the same formula as above for setting the cutoff rate.
CV 55 is used to set the exhaust tone and may be programmed with any value between 0 and 63 (0x3F). Higher
values will produce a steamier exhaust chuff.
CV 56 is used to adjust exhaust volume when the DDE processor is disabled and may be programmed to any value
between 0 and 255 (0xFF). Higher values will produce a louder exhaust.