diff --git a/ruby/lib/jam_ruby/connection_manager.rb b/ruby/lib/jam_ruby/connection_manager.rb
index faa505096..02a0f6891 100644
--- a/ruby/lib/jam_ruby/connection_manager.rb
+++ b/ruby/lib/jam_ruby/connection_manager.rb
@@ -369,23 +369,21 @@ SQL
       end
     end
 
-    # if a blk is passed in, upon success, it will be called and you can issue notifications
-    # within the connection table lock
-    def join_music_session(user, client_id, music_session, as_musician, tracks, &blk)
+    def join_music_session(user, client_id, music_session, as_musician, tracks)
       connection = nil
-      user_id = user.id
-      music_session_id = music_session.id
 
       ConnectionManager.active_record_transaction do |connection_manager|
         db_conn = connection_manager.pg_conn
 
-        connection = Connection.find_by_client_id_and_user_id!(client_id, user_id)
-        connection.music_session_id = music_session_id
-        connection.as_musician = as_musician
-        connection.joining_session = true
-        connection.joined_session_at = Time.now
-        associate_tracks(connection, tracks)
-        connection.save
+        connection = Connection.find_by_client_id_and_user_id!(client_id, user.id)
+
+        connection.join_the_session(music_session, as_musician, tracks)
+        # connection.music_session_id = music_session.id
+        # connection.as_musician = as_musician
+        # connection.joining_session = true
+        # connection.joined_session_at = Time.now
+        # associate_tracks(connection, tracks)
+        # connection.save
 
         if connection.errors.any?
           raise ActiveRecord::Rollback
@@ -419,7 +417,7 @@ SQL
         end
 
         # can throw exception if the session is deleted just before this
-        conn.exec("UPDATE connections SET music_session_id = NULL, joined_session_at = NULL, as_musician = NULL WHERE client_id = $1 AND user_id =$2", [client_id, user_id]) do |result|
+        conn.exec("UPDATE connections SET music_session_id = NULL, joined_session_at = NULL, as_musician = NULL WHERE client_id = $1 AND user_id = $2 AND music_session_id = $3", [client_id, user_id, music_session_id]) do |result|
           if result.cmd_tuples == 1
             @log.debug("disassociated music_session with connection for client_id=#{client_id}, user_id=#{user_id}")
 
@@ -442,23 +440,23 @@ SQL
       conn.exec("LOCK connections IN EXCLUSIVE MODE").clear
     end
 
-    def associate_tracks(connection, tracks)
-      @log.debug "Tracks:"
-      @log.debug tracks
-      connection.tracks.clear()
-
-      unless tracks.nil?
-        tracks.each do |track|
-          instrument = Instrument.find(track["instrument_id"])
-          t = Track.new
-          t.instrument = instrument
-          t.connection = connection
-          t.sound = track["sound"]
-          t.client_track_id = track["client_track_id"]
-          t.save
-          connection.tracks << t
-        end
-      end
-    end
+    # def associate_tracks(connection, tracks)
+    #   @log.debug "Tracks:"
+    #   @log.debug tracks
+    #   connection.tracks.clear()
+    #
+    #   unless tracks.nil?
+    #     tracks.each do |track|
+    #       instrument = Instrument.find(track["instrument_id"])
+    #       t = Track.new
+    #       t.instrument = instrument
+    #       t.connection = connection
+    #       t.sound = track["sound"]
+    #       t.client_track_id = track["client_track_id"]
+    #       t.save
+    #       connection.tracks << t
+    #     end
+    #   end
+    # end
   end
 end
diff --git a/ruby/lib/jam_ruby/models/connection.rb b/ruby/lib/jam_ruby/models/connection.rb
index cf282c357..8e9836c30 100644
--- a/ruby/lib/jam_ruby/models/connection.rb
+++ b/ruby/lib/jam_ruby/models/connection.rb
@@ -68,6 +68,13 @@ module JamRuby
     
     def can_join_music_session
 
+      # puts "can_join_music_session: #{music_session_id} was #{music_session_id_was}" if music_session_id_changed?
+
+      if music_session_id_changed? and !(music_session_id_was.nil? or music_session_id_was.blank?)
+        errors.add(:music_session, ValidationMessages::CANT_JOIN_MULTIPLE_SESSIONS)
+        return false
+      end
+
       if music_session.nil?
         errors.add(:music_session, ValidationMessages::MUSIC_SESSION_MUST_BE_SPECIFIED)
         return false
@@ -139,14 +146,35 @@ module JamRuby
       true
     end
 
-    def join_the_session(music_session, as_musician)
-      self.music_session = music_session
+    def join_the_session(music_session, as_musician, tracks)
+      self.music_session_id = music_session.id
       self.as_musician = as_musician
       self.joining_session = true
       self.joined_session_at = Time.now
-      self.save!
+      associate_tracks(tracks) unless tracks.nil?
+      self.save
     end
 
+    def associate_tracks(tracks)
+      # @log.debug "Tracks:"
+      # @log.debug tracks
+
+
+      unless tracks.nil?
+        self.tracks.clear()
+        tracks.each do |track|
+          t = Track.new
+          t.instrument = Instrument.find(track["instrument_id"])
+          t.connection = self
+          t.sound = track["sound"]
+          t.client_track_id = track["client_track_id"]
+          t.save # todo what if it fails?
+          self.tracks << t
+        end
+      end
+    end
+
+
     private
 
     def require_at_least_one_track_when_in_session
diff --git a/ruby/spec/jam_ruby/connection_manager_spec.rb b/ruby/spec/jam_ruby/connection_manager_spec.rb
index ee492fa41..c1e52c44d 100644
--- a/ruby/spec/jam_ruby/connection_manager_spec.rb
+++ b/ruby/spec/jam_ruby/connection_manager_spec.rb
@@ -490,34 +490,57 @@ describe ConnectionManager do
   end
 
   it "join_music_session fails if user has music_session already active" do
+
+    # there are two different problems: user can only be in one active music_session at a time,
+    # and a connection can only point to one active music_session at a time. this is a test of
+    # the former but we need a test of the latter, too.
+
     pending
+
+  end
+
+  it "join_music_session fails if connection has music_session already active" do
+
+    # there are two different problems: user can only be in one active music_session at a time,
+    # and a connection can only point to one active music_session at a time. this is a test of
+    # the latter but we need a test of the former, too.
+
+
     user_id = create_user("test", "user11", "user11@jamkazam.com")
 
     user = User.find(user_id)
-    music_session = MusicSession.find(create_music_session(user_id))
 
-    client_id = Faker::Number.number(20)
-    @connman.create_connection(user_id, client_id, "1.1.1.1", 'client')
-    connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
+    client_id1 = Faker::Number.number(20)
+    @connman.create_connection(user_id, client_id1, "1.1.1.1", 'client')
+    music_session1 = MusicSession.find(create_music_session(user_id))
+    connection1 = @connman.join_music_session(user, client_id1, music_session1, true, TRACKS)
 
-    client_id = Faker::Number.number(20)
-    @connman.create_connection(user_id, client_id, Faker::Internet.ip_v4_address, 'client')
-    music_session = MusicSession.find(create_music_session(user_id))
-    connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
+    connection1.errors.size.should == 0
 
-    connection.errors.size.should == 1
-    connection.errors.get(:music_session).should == [ValidationMessages::CANT_JOIN_MULTIPLE_SESSIONS]
+    music_session2 = MusicSession.find(create_music_session(user_id))
+    connection2 = @connman.join_music_session(user, client_id1, music_session2, true, TRACKS)
 
-    user.update_attribute(:admin, true)
-    client_id = Faker::Number.number(20)
-    @connman.create_connection(user_id, client_id, "1.1.1.1", 'client')
-    music_session = MusicSession.find(create_music_session(user_id))
-    connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
-    client_id = Faker::Number.number(20)
-    @connman.create_connection(user_id, client_id, Faker::Internet.ip_v4_address, 'client')
-    music_session = MusicSession.find(create_music_session(user_id))
-    connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
-    connection.errors.size.should == 0
+    connection2.errors.size.should == 1
+    connection2.errors.get(:music_session).should == [ValidationMessages::CANT_JOIN_MULTIPLE_SESSIONS]
+
+    # client_id2 = Faker::Number.number(20)
+    # @connman.create_connection(user_id, client_id2, "2.2.2.2", 'client')
+    # music_session2 = MusicSession.find(create_music_session(user_id))
+    # connection2 = @connman.join_music_session(user, client_id2, music_session2, true, TRACKS)
+    #
+    # connection2.errors.size.should == 1
+    # connection2.errors.get(:music_session).should == [ValidationMessages::CANT_JOIN_MULTIPLE_SESSIONS]
+    #
+    # user.update_attribute(:admin, true)
+    # client_id = Faker::Number.number(20)
+    # @connman.create_connection(user_id, client_id, "1.1.1.1", 'client')
+    # music_session = MusicSession.find(create_music_session(user_id))
+    # connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
+    # client_id = Faker::Number.number(20)
+    # @connman.create_connection(user_id, client_id, Faker::Internet.ip_v4_address, 'client')
+    # music_session = MusicSession.find(create_music_session(user_id))
+    # connection = @connman.join_music_session(user, client_id, music_session, true, TRACKS)
+    # connection.errors.size.should == 0
   end
 
 end
diff --git a/ruby/spec/jam_ruby/models/claimed_recording_spec.rb b/ruby/spec/jam_ruby/models/claimed_recording_spec.rb
index 42bb0148f..fae09a6ab 100644
--- a/ruby/spec/jam_ruby/models/claimed_recording_spec.rb
+++ b/ruby/spec/jam_ruby/models/claimed_recording_spec.rb
@@ -21,7 +21,7 @@ describe ClaimedRecording do
     @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)
     # @music_session.connections << @connection
     @music_session.save
-    @connection.join_the_session(@music_session, true)
+    @connection.join_the_session(@music_session, true, nil)
     @recording = Recording.start(@music_session, @user)
     @recording.stop
     @recording.reload
diff --git a/ruby/spec/jam_ruby/models/mix_spec.rb b/ruby/spec/jam_ruby/models/mix_spec.rb
index fe4f84a54..7acb05f81 100755
--- a/ruby/spec/jam_ruby/models/mix_spec.rb
+++ b/ruby/spec/jam_ruby/models/mix_spec.rb
@@ -10,7 +10,7 @@ describe Mix do
     @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)
     # @music_session.connections << @connection
     @music_session.save
-    @connection.join_the_session(@music_session, true)
+    @connection.join_the_session(@music_session, true, nil)
     @recording = Recording.start(@music_session, @user)
     @recording.stop
 	  @recording.claim(@user, "name", "description", Genre.first, true)
diff --git a/ruby/spec/jam_ruby/models/music_session_spec.rb b/ruby/spec/jam_ruby/models/music_session_spec.rb
index adcaa485b..f76e264a8 100644
--- a/ruby/spec/jam_ruby/models/music_session_spec.rb
+++ b/ruby/spec/jam_ruby/models/music_session_spec.rb
@@ -398,7 +398,7 @@ describe MusicSession do
       @music_session = FactoryGirl.create(:music_session, :creator => @user1, :musician_access => true)
       # @music_session.connections << @connection
       @music_session.save!
-      @connection.join_the_session(@music_session, true)
+      @connection.join_the_session(@music_session, true, nil)
     end
 
     describe "not recording" do
diff --git a/ruby/spec/jam_ruby/models/musician_search_spec.rb b/ruby/spec/jam_ruby/models/musician_search_spec.rb
index 20be14059..a3c1bdf07 100644
--- a/ruby/spec/jam_ruby/models/musician_search_spec.rb
+++ b/ruby/spec/jam_ruby/models/musician_search_spec.rb
@@ -115,7 +115,7 @@ describe 'Musician search' do
     music_session = FactoryGirl.create(:music_session, :creator => usr, :musician_access => true)
     # music_session.connections << connection
     music_session.save
-    connection.join_the_session(music_session, true)
+    connection.join_the_session(music_session, true, nil)
     recording = Recording.start(music_session, usr)
     recording.stop
     recording.reload
@@ -130,7 +130,7 @@ describe 'Musician search' do
     music_session = FactoryGirl.create(:music_session, :creator => usr, :musician_access => true)
     # music_session.connections << connection
     music_session.save
-    connection.join_the_session(music_session, true)
+    connection.join_the_session(music_session, true, nil)
   end
 
   context 'musician stat counters' do
diff --git a/ruby/spec/jam_ruby/models/recording_spec.rb b/ruby/spec/jam_ruby/models/recording_spec.rb
index 7fc0f31d2..56ccf176a 100644
--- a/ruby/spec/jam_ruby/models/recording_spec.rb
+++ b/ruby/spec/jam_ruby/models/recording_spec.rb
@@ -80,7 +80,7 @@ describe Recording do
     @track2 = FactoryGirl.create(:track, :connection => @connection2, :instrument => @instrument2)
     
     # @music_session.connections << @connection2
-    @connection2.join_the_session(@music_session, true)
+    @connection2.join_the_session(@music_session, true, nil)
 
     @recording = Recording.start(@music_session, @user)
     @user.recordings.length.should == 0
@@ -179,7 +179,7 @@ describe Recording do
     @track = FactoryGirl.create(:track, :connection => @connection2, :instrument => @instrument)
     # @music_session.connections << @connection2
     @music_session.save
-    @connection2.join_the_session(@music_session, true)
+    @connection2.join_the_session(@music_session, true, nil)
     @recording = Recording.start(@music_session, @user)
     @recording.stop
     @recording.reload
diff --git a/ruby/spec/jam_ruby/resque/audiomixer_spec.rb b/ruby/spec/jam_ruby/resque/audiomixer_spec.rb
index a1cd67c77..94918bc9e 100644
--- a/ruby/spec/jam_ruby/resque/audiomixer_spec.rb
+++ b/ruby/spec/jam_ruby/resque/audiomixer_spec.rb
@@ -157,7 +157,7 @@ describe AudioMixer do
       @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)
       # @music_session.connections << @connection
       @music_session.save
-      @connection.join_the_session(@music_session, true)
+      @connection.join_the_session(@music_session, true, nil)
       @recording = Recording.start(@music_session, @user)
       @recording.stop
       @recording.claim(@user, "name", "description", Genre.first, true)
diff --git a/web/spec/controllers/api_claimed_recordings_spec.rb b/web/spec/controllers/api_claimed_recordings_spec.rb
index f1977d400..7c4b39560 100644
--- a/web/spec/controllers/api_claimed_recordings_spec.rb
+++ b/web/spec/controllers/api_claimed_recordings_spec.rb
@@ -11,7 +11,7 @@ describe ApiClaimedRecordingsController do
     @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)      
     # @music_session.connections << @connection
     @music_session.save
-    @connection.join_the_session(@music_session, true)
+    @connection.join_the_session(@music_session, true, nil)
     @recording = Recording.start(@music_session, @user)
     @recording.stop
     @recording.reload
diff --git a/web/spec/features/social_meta_spec.rb b/web/spec/features/social_meta_spec.rb
index ca368dc60..db5dc403f 100644
--- a/web/spec/features/social_meta_spec.rb
+++ b/web/spec/features/social_meta_spec.rb
@@ -65,7 +65,7 @@ describe "social metadata" do
       ms = FactoryGirl.create(:music_session, :creator => user, :musician_access => true)
       # ms.connections << connection
       ms.save!
-      connection.join_the_session(ms, true)
+      connection.join_the_session(ms, true, nil)
       ms
     }
 
@@ -93,7 +93,7 @@ describe "social metadata" do
       @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)
       # @music_session.connections << @connection
       @music_session.save
-      @connection.join_the_session(@music_session, true)
+      @connection.join_the_session(@music_session, true, nil)
       @recording = Recording.start(@music_session, @user)
       @recording.stop
       @recording.reload
diff --git a/web/spec/helpers/recording_helper_spec.rb b/web/spec/helpers/recording_helper_spec.rb
index 1220abc3e..30ef78ff2 100644
--- a/web/spec/helpers/recording_helper_spec.rb
+++ b/web/spec/helpers/recording_helper_spec.rb
@@ -10,7 +10,7 @@ describe MusicSessionHelper do
     @music_session = FactoryGirl.create(:music_session, :creator => @user, :musician_access => true)
     # @music_session.connections << @connection
     @music_session.save
-    @connection.join_the_session(@music_session, true)
+    @connection.join_the_session(@music_session, true, nil)
     @recording = Recording.start(@music_session, @user)
     @recording.stop
     @recording.reload
diff --git a/web/spec/requests/music_sessions_api_spec.rb b/web/spec/requests/music_sessions_api_spec.rb
index bc453960d..592a375c9 100755
--- a/web/spec/requests/music_sessions_api_spec.rb
+++ b/web/spec/requests/music_sessions_api_spec.rb
@@ -700,7 +700,7 @@ describe "Music Session API ", :type => :api do
     music_session = FactoryGirl.create(:music_session, :creator => user, :musician_access => true)
     # music_session.connections << connection
     music_session.save
-    connection.join_the_session(music_session, true)
+    connection.join_the_session(music_session, true, nil)
     recording = Recording.start(music_session, user)
     recording.stop
     recording.reload
diff --git a/web/spec/requests/users_api_spec.rb b/web/spec/requests/users_api_spec.rb
index 8d3c18d5c..07dd6eae4 100644
--- a/web/spec/requests/users_api_spec.rb
+++ b/web/spec/requests/users_api_spec.rb
@@ -985,7 +985,7 @@ describe "User API", :type => :api do
         ms = FactoryGirl.create(:music_session, :creator => user, :musician_access => true)
         # ms.connections << connection
         ms.save!
-        connection.join_the_session(ms, true)
+        connection.join_the_session(ms, true, nil)
         ms }
 
       it "fetches facebook successfully" do
@@ -1122,7 +1122,7 @@ describe "User API", :type => :api do
           @music_session = FactoryGirl.create(:music_session, :creator => user, :musician_access => true)
           # @music_session.connections << @connection
           @music_session.save
-          @connection.join_the_session(@music_session, true)
+          @connection.join_the_session(@music_session, true, nil)
           @recording = Recording.start(@music_session, user)
           @recording.stop
           @recording.reload