The *Plugin SDK supports Soundcloud embeds, using an iframe implementation. To get started, generate an embed code for your Soundcloud media by following the instructions at: https://help.soundcloud.com/hc/en-us/articles/115003568008-Embedding-a-track-or-playlist-.
To add the video to your interactive transcript, simply place the embed in your P3SDK div, and add an id to the iframe that is identical to your player_id (highlighted in pink):
<div class="p3sdk-container p3sdk-debug" player_id="soundcloud-player-6" player_type="soundcloud">
<iframe id="soundcloud-player-6" width="100%" height="450" scrolling="no" frameborder="no" src="https://w.soundcloud.com/player/?url=https%3A//api.soundcloud.com/tracks/233351852&auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&visual=true"></iframe>
To get the transcript and player to work, you will need to embed Soundcloud's Widget API on your page.
*The Plugin SDK is sometimes referred to as "P3SDK"
This information is useful to me as a new user of SoundCloud. Thumbs up!