(function(module) {
	"use strict";

	var SoundCloud = {},
		embed = '<iframe width="100%" height="166" scrolling="no" frameborder="no" src="https://w.soundcloud.com/player/?url=https://soundcloud.com/$1&amp;auto_play=false&amp;hide_related=false&amp;show_artwork=true"></iframe>';


	SoundCloud.parse = function(postContent, callback) {
		// modified from http://stackoverflow.com/questions/7168987/
		postContent = postContent.replace(/<a href="(?:https?:\/\/)?(?:www\.)?(?:soundcloud\.com)\/?(.+)">.+<\/a>/g, embed);
		callback(null, postContent);
	};

	module.exports = SoundCloud;
}(module));

                <iframe width="100%" height="450" scrolling="no" frameborder="no" src="https://w.soundcloud.com/player/?url=https%3A//api.soundcloud.com/playlists/29817339&amp;auto_play=false&amp;hide_related=false&amp;show_artwork=true"></iframe>
(function(module) {
    "use strict";
    var Soundcloud = {},
        embed = '<iframe width="100%" height="166" scrolling="no" frameborder="no" src="https://w.soundcloud.com/player/?url=https://soundcloud.com/$1/$2&amp;show_artwork=true"></iframe>',
        embeds = '<iframe width="100%" height="410" scrolling="no" frameborder="no" src="https://w.soundcloud.com/player/?url=https://soundcloud.com/$1/sets/$2&amp;show_artwork=true"></iframe>'
    var	embedtrack = /<a href="(?:https?:\/\/)?(?:www\.)?(?:soundcloud\.com)\/?([\w\-_]+)\/([\w\-_]+)">.+<\/a>/g;
    var	embedset = /<a href="(?:https?:\/\/)?(?:www\.)?(?:soundcloud\.com)\/?([\w\-_]+)\/sets\/([\w\-_]+)">.+<\/a>/g;


    Soundcloud.parse = function(data, callback) {

        if (!data || !data.postData || !data.postData.content) {
            return callback(null, data);
        }
        if (data.postData.content.match(embedtrack)) {
            data.postData.content = data.postData.content.replace(embedtrack, embed);
        }
        if (data.postData.content.match(embedset)) {
            data.postData.content = data.postData.content.replace(embedset, embeds);
        }

        callback(null, data);
    };

    module.exports = Soundcloud;
}(module));

Update to support soundcloud sets.
Update to support soundcloud sets.