H0 Sound Decoder MX640 Page 33
CV
Designation
Value
range
INC
steps
De-
fault
Description
not usually done. CV #274 causes the blow-off
sound to be suppressed if the engine wasn’t
standing still for the time defined here.
Value in CV #274 = time in tenths of a second!
Shunting with permanently open cylinder valves
can be achieved by actuating the function key that
is assigned for blow-off sound (F4 by default or by
function key assignment with CV #312 = 2, 3, 4…,
see above).
To set up load dependent sound do the follow-
ing in the order shown:
“Automated recording of the motor’s “basic load”
factor”; see above!
Adjusting sound volume in CV #275 and #276.
Adjusting CV #277 (should have been “0” up to
this point), see below!
If required also CV #278 and #279.
LEAD
- CV
#275
Engine (chuff) sound
volume at low speed
and no-load
0 - 255
10
60
With this CV the chuff volume at “basic load” (that
is under the same conditions as during the auto-
mated recording run) is adjusted at a speed of
about 1/10 of full speed.
Note: For practical purposes (but not absolutely
necessary), CV #275 is set to the proper value by
trial using the “incremental programming” at low
speed. Because the volume at various speeds is
interpolated between the values in CV #275 and
#277 it is
not
necessary to run at an exact speed
step during this set-up, as long as it is around
1/10 of full speed.
This adjustment is best performed with CV #277
set to “0” (default) so that the setting for “unloaded
driving” is not influenced by load factors.
#276
Engine (chuff) sound
volume at high
speed and no-load
0 - 255
10
80
Same procedure as in CV #275 above, but for
high speed.
CV #276 defines the “no-load” chuff sound volume
at full speed. Set the speed regulator to maximum
during this set-up.
All notes in CV #275 are also valid for this CV!
#277
Degree of volume
change under load
for driving (chuff)
sound.
0 - 255
10
0
=
no
change
When deviating from the basic load (as deter-
mined by the “Automated recording of the motor’s
“basic load” factor”, see above) the chuff beat vol-
ume should be increasing (on inclines) or de-
creasing (or muted) on declines.
CV #277 defines the degree of change, which is
to be set to the proper value by trial.
LEAD
- CV
Load change
threshold
0 - 255
10
0
With this CV, a change in sound to small load
changes can be suppressed (i.e. in curves) in or-
CV
Designation
Value
range
INC
steps
De-
fault
Description
#278
der to prevent chaotic sound impressions.
Suitable settings can only be determined by trial
(with “incremental programming).
#279
Reaction time to load
change
0 - 255
1
0
With this CV the reactions in sound to changes in
load can be delayed, whereas the factor is not just
time but rather “load-change dependent time” (=
the bigger the change the faster the effect). This
CV is also used to suppress chaotic sound
changes.
Suitable settings can only be determined by trial
(with “incremental programming” of CV’s #278
and #279 together).
#280
Load influence
For DIESEL engines
0 - 255
10
0
This CV determines (at least temporarily in SW
version 15) the reaction of the diesel sound to
load: RPM levels and load steps of diesel-
hydraulic engines, cruise/idle rpm of diesel-
electrics and shift points of geared engines.
= 0: no influence, dependent on motor rpm
= to 255: large influence.
It is highly recommended that the automated
test
run
with CV #302 = 75 is performed first (see text
above under CV #302).
LEAD
- CV
#281
Acceleration
threshold for full load
sound
0 – 255
(internal
speed
steps)
1
1
Compared to the “basic load”, more powerful and
louder chuff sounds should be played back for in-
creased power requirements during accelerations.
As is the case with the prototype, the increased
sound should be noticeable before the increase in
speed becomes visible, since the latter is a result
of the increased steam volume supplied to the pis-
tons. It is therefore practical that the heavy accel-
eration sound is played back when the speed has
increased by just one speed step (when no real
speed change is noticed), to be able to control the
proper sound sequence with the speed regulator.
The “engineer” can in this fashion adjust the
sound (by increasing the speed by 1 step) in an-
ticipation of an imminent incline.
=1: Acceleration sound played back at full volume
if speed has increased by just one speed step.
= 2, 3…. Acceleration sound played back at full
volume only after increasing speed by this number
of speed steps; before that: proportional volume.
#282
Duration of
acceleration sound
0 - 255
=
0 - 25 sec
10
30
=
3 sec
The acceleration sound should remain for a cer-
tain length of time after the speed increased (oth-
erwise each single speed step would be audible,
which is unrealistic).
Value in CV #282 = time in tenths of a second!
#283
Engine sound
0 - 255
10
255
The volume of steam chuffs at maximum accel-
