Use an expression to trigger a sound file?

Question

I have a comp with many layers. At the beginning of each layer, I want to play an AIFF file (the same one for every layer).
Rather than adding the AIFF asset to the project over and over, is there a way to add the sound file to the comp once, and then add an expression to each layer to play that sound at the layer's in point?

Answer 1

Try enabling Time Remapping on the audio layer and apply the following expression:
> firstLayer = thisComp.layer("Medium Yellow Solid 2");
lastLayer = thisComp.layer("Medium Yellow Solid 3");
recentLayer = firstLayer;
for(i = firstLayer.index; i <= lastLayer.index; i++){
currentLayer = thisComp.layer(i);
timeDiff = time - currentLayer.inPoint;
if(timeDiff >= 0 && currentLayer.inPoint > recentLayer.inPoint) recentLayer = currentLayer;
time - recentLayer.inPoint
Substitute the names of the first and last layers you want to trigger the sound in the first two lines.
It might be necessary to put a similar expression on the audio levels to eliminate artifacts at the beginning and end of each instance of playback, though.