Safari and Chrome browsers can only play one media file at a time on Apple iOS devices. As a result, we don't recommend triggering multiple audio or video resources to play at the same time in a Storyline course if your learners are using iPads or iPhones. This limitation can also impact step-by-step screen recordings if they include both audio and video components.
Here's a tip: Simultaneous playback of multiple audio/video resources is supported in the Articulate Mobile Player app, which is available for iPads. Just include Articulate Mobile Player output when you publish your Storyline course.