Manipulating the jumppad sound is a bit more difficult. At the moment
we use a normal jumppad with a trigger_push and a target_position. If
we want to change the sound we also have to change the whole jumppad
construction since the basic one only plays the default one.
First, we convert the trigger_push into a trigger_multiple. Then we add a target_push and place it directly into the middle of the trigger. Now we connect the trigger with the target_push and the target_push with the target_position (or an info_notnull) we already have.
The target_position tells the target_push where to go and how much
velocity to use. The target_push gets activated by the trigger. So, now
that you have the right values for the jumppad, you actually could
place the target_push + target_position combination whereever you want
(I did that in the finalised versions of the maps).
What's missing is the target_speaker which will play our sound. You need to place this one right in front of the jumppad since the sound comes from the pad. Connect the trigger with the target_speaker.
Set the right path for the sound file in the entity window.
For the spawnflags you have three options. You could tick the
"activator" box so only the "jumper" hears the jumppad sound, or you
tick the "global" box so anybody can hear it everywhere, or you just
leave it and everybody who is near the jumppad hears the sound.
With all the effects in the background now, I can't hear the jumppad sound at all. To make it louder just connect the trigger with several speakers or just copy one.
Add: I forgot to clip the back of the jumppad. Anyone who touches the trigger from behind the pad, of course also gets pushed. So clip it properly.