As @sixhours suggested in the previous thread, we don’t recommend that you do this because it may be more trouble than it’s worth. We can’t guarantee that this will work on all browsers and mobile devices. It may lead to other display problems that we may not have a solution or workaround for.
It’s also not possible to display a different sound cloud player on on each post.
That said, if you’d still like to give it a shot given these limitations, here are the steps:
1. Create a new Text Widget.
2. Paste the soundcloud shortcode from your above post into this widget.
After you have done those two steps, reply back here and I will guide you through the next few steps.