Use of Audio in courses

I am interested in opinions on how best to trigger/use audio in courses.

The audience the course is for may not all necessarily have access to audio.

The instructional designer has requested audio on every slide cued to come in with various pictures and text. The audio matches the text

My questions is , is it best to trigger the audio to play when timelive starts? or would it be better to enable the learner to switch the audio on if they wish - triggered by an audio button, which is the approach I have used in previous courses where audio has provided additional information to the text.