Can automator's Filter Finder Items process music based on length?
Lets assume you have some action that's passing off files to a Filter Finder Items action, set as Find files where: All of the following are true and Kind is music.

This ensures what's passed to the next action, a Run Shell Script action, set as Shell: /bin/bash and Pass input as arguments are music files.

Replace the default code in the Run Shell Script action, having the above settings, with the following code:

for f in "$@"; do
    d="$(afinfo -r "$f" | awk '/estimated duration:/{print int($3)}')"
    if [[ $d -lt 2 ]]; then
        echo "$f"
    fi
done


The results of the above code with be the fully qualified pathname of music files with less than a 2 second duration and is passed to the next action as a list.



To address your second comment to my original answer, use the following code in place of the code above:

for f in "$@"; do
    d="$(afinfo -r "$f" | awk '/estimated duration:/{print $3}')"
    if (( $(echo "1.5 &gt; $d" | bc -l) )); then
        echo "$f"
    fi
done