Chunk of JS from a larger project illustrating how to use the SoundCloud API to construct a basic player with playlist, seek and basic control functionality.

SoundCloud Player

// Initialize the Soundcloud API and set up player functionality
Soundcloud: {
	// Start the API up
	Init: function () {
		SC.initialize({
			client_id: app.Config.soundcloudClient
		});

		// For each audio player, bind soundcloud functionality
		$('.audio-player').each( function () {
			var player = $(this);

			// Retrieve the soundcloud URL from the content
			if ( $(this).find('.audio-url').length ) {
				var url = $(this).find('.audio-url').text();

				// If the URL is valid, get the correct API resource
				if ( url ) {
					// Resolve the passed URL into an API-usable URL and play the resulting ID
					app.Component.Soundcloud.Resolve( url, function ( track_info ) {
						// If that went well, set up player (handled differently for sets/tracks)
						// 'user' is also a potential type that could be played but isn't handled
						// currently
						if ( track_info ) {
							if ( track_info.kind == 'playlist' ) {

								// Build the playlist
								var playlist = _.template( app.Templates.soundcloud_playlist, {
									tracks: track_info.tracks
								});

								// Append the playlist to the player
								if ( playlist ) {
									player.find('.playlist').append( playlist );

									// Refresh the layout because the height will have changed
									app.Component.Stackery.Init();

									// Set up individual track controls
									player.find('.playlist li').click( function () {
										app.Component.Soundcloud.PlayTrack( $(this), player );
									});
								}

							} else if ( track_info.kind == 'track' ) {

								// Placeholder for single-track functionality (may need later)

							}

							// Bind generic audio controls
							player.find('.progress-bar').click( function ( event ) {
								var track = App.Config.currentTrack;

								if ( track ) {
									var offset = event.offsetX;

									if ( offset ) {
										var new_position = Math.floor( ( offset / $(this).width() ) * track.duration );
										
										if ( new_position && new_position <= track.duration ) {
											track.setPosition( new_position );
										}
									}
								}
							});
							player.find('.controls .play-pause').click( function () {
								var track = App.Config.currentTrack;

								// Usual play/oause functionality if there's a track loaded
								if ( track ) {
									$(this).toggleClass( 'play' );

									if ( $(this).hasClass( 'play' ) ) {
										track.pause();
									} else {
										track.play();
									}

								// Otherwise load the first track if not
								} else {
									app.Component.Soundcloud.PlayTrack( player.find('.soundcloud-playlist li').first(), player );
								}
							});
							player.find('.controls .previous').click( function () {
								// Find and play previous track only if it exists
								var playing = player.find('.playlist .playing');

								if ( playing.length && playing.prev('li').length ) {
									var previous = playing.prev('li');

									// And away we go
									app.Component.Soundcloud.PlayTrack( previous, player );
								}
							});
							player.find('.controls .next').click( function () {
								// Find and play next track only if it exists
								var playing = player.find('.playlist .playing');

								if ( playing.length && playing.next('li').length ) {
									var next = playing.next('li');

									// And away we go
									app.Component.Soundcloud.PlayTrack( next, player );
								}
							});
							player.find('.volume-bar').click( function ( event ) {
								var track = App.Config.currentTrack;
								
								if ( track ) {
									var offset = event.offsetX;

									if ( offset ) {
										var new_position = Math.floor( ( offset / $(this).width() ) * 100 );
										
										if ( new_position ) {
											// Gate the new value to valid values
											if ( new_position < 0 ) new_position = 0;
											if ( new_position > 100 ) new_position = 100;

											track.setVolume( new_position );
											$(this).find('.inner').css( 'width', new_position.toString() + '%' );
										}
									}
								}
							});
							player.find('.volume-icon').click( function () {
								var track = App.Config.currentTrack;

								if ( track ) {
									$(this).toggleClass( 'muted' );

									if ( $(this).hasClass('muted') ) {
										track.mute();
									} else {
										track.unmute();
									}
								}
							});
						}	
					});	
				}	
			}
		});
	},

	// Retrieve track/user/set information for a specified soundcloud URL
	Resolve: function ( url, callback ) {
		$.getJSON( 'http://api.soundcloud.com/resolve.json?callback=?', {
			url: url,
			client_id: app.Config.soundcloudClient
		}, function ( response ) {
			if ( callback ) callback( response );
		});
	},

	// Play an audio track utilizing Soundcloud functions below
	PlayTrack: function ( track_element, player ) {
		var stream_url = track_element.find('.stream-url').text();

		if ( stream_url ) {
			// Update the track duration
			player.find('.total-time').text( app.__.MillisecondsToMinutes( track_element.find('.duration').text() ) );

			// Play the track and update progress while playing
			app.Component.Soundcloud.StreamTrack( stream_url, function ( sound ) {
				// Set volume to default level on load
				sound.setVolume( 75 );

				// Update playing icon
				player.find('.controls .play-pause').removeClass( 'play' );
			},

			// While playing, update progress
			function ( sound ) {
				// Progress bar
				var progress = player.find('.progress-bar'),
					inner = progress.children('.inner'),
					position = Math.ceil( progress.width() * ( sound.position / sound.duration ) );

				inner.width( position );

				// Current play time
				var current_time = player.find('.current-time'),
					converted = app.__.MillisecondsToMinutes( sound.position );

				current_time.text( converted );
			},

			// On finish, jump to next track if it exists
			function ( sound ) {
				// Find and play next track only if it exists
				var playing = player.find('.playlist .playing');

				if ( playing.length && playing.next('li').length ) {
					var next = playing.next('li');

					// And away we go
					app.Component.Soundcloud.PlayTrack( next, player );
				}
			});

			// Update track's playing status
			track_element.addClass( 'playing' ).siblings().removeClass( 'playing' );
		}
	},

	// Play a single track over the Soundcloud API with the specified stream_url.
	// Will provide the created SoundManager object in App.Config.CurrentTrack
	StreamTrack: function ( stream_url, loaded, playing, finished ) {
		if ( SC ) {
			SC.stream( stream_url, function ( sound ) {
				// If an existing track exists, null it out before switching
				if ( app.Config.currentTrack ) app.Config.currentTrack.destruct();

				// Save a reference to the current track and play the track
				app.Config.currentTrack = sound;
				sound.play({
					whileplaying: function () {
						if ( playing ) playing( this );
					},
					onload: function () {
						if ( loaded ) loaded( this );
					},
					onfinish: function () {
						if ( finished ) finished( this );
					}
				});
			});
		}	
	}
}