speech-dispatcher makes all audio crackle

Symptom

speech-dispatcher package causes audio from speaker crackle (noise and delay) since Ubuntu 18.04 .

Test

To verify the symptom, run the following script and your speaker must be crackle!

spd-say Hello!

Solution

Run the following script to solve the problem temporarily.

killall speech-dispatcher

Run the following script to solve the problem permanently.

killall speech-dispatcher
sudo sed -i 's/# AudioOutputMethod "pulse"/AudioOutputMethod "libao"/g' /etc/speech-dispatcher/speechd.conf