diff --git a/aircox_liquidsoap/management/commands/liquidsoap.py b/aircox_liquidsoap/management/commands/liquidsoap.py
index 9c73cf4..19dba2a 100644
--- a/aircox_liquidsoap/management/commands/liquidsoap.py
+++ b/aircox_liquidsoap/management/commands/liquidsoap.py
@@ -47,7 +47,7 @@ class Command (BaseCommand):
             delay = options.get('delay') / 1000
             while True:
                 for controller in self.monitor.controllers.values():
-                    controller.dealer.monitor()
+                    controller.monitor()
                 time.sleep(delay)
 
 
diff --git a/aircox_liquidsoap/utils.py b/aircox_liquidsoap/utils.py
index d1c8336..935dd71 100644
--- a/aircox_liquidsoap/utils.py
+++ b/aircox_liquidsoap/utils.py
@@ -241,13 +241,6 @@ class Dealer (Source):
     def stream_info (self):
         pass
 
-    def get_next_diffusion (self):
-        diffusions = models.Diffusion.get_next(self.station)
-        if not diffusions.count():
-            return
-        diffusion = diffusions[0]
-        return diffusion
-
     @property
     def on (self):
         r = self.connector.send('var.get ', self.id, '_on')
@@ -314,11 +307,18 @@ class Dealer (Source):
 
         # run the diff
         if self.playlist == diff.playlist and diff.date <= now:
-            # FIXME: log
             self.on = True
             for source in self.controller.source:
                 source.skip()
 
+            self.controller.log(
+                source = self.id,
+                diffusion = diff,
+                date = now,
+                comment = 'trigger the scheduled diffusion to liquidsoap; '
+                          'skip all other sources',
+            )
+
 
 class Controller:
     connector = None
@@ -369,11 +369,13 @@ class Controller:
             return self.dealer
         return self.streams.get(source_id)
 
-    def next_diffusions (self, count = 5):
+    def log (self, **kwargs):
         """
-        Return a list of the count next diffusions
+        Create a log using **kwargs, and print info
         """
-        return models.Diffusion.get_next(self.station)[:count]
+        log = models.Log(**kwargs)
+        log.save()
+        log.print()
 
     def update_all (self):
         """
@@ -384,6 +386,31 @@ class Controller:
         for source in self.streams.values():
             source.update()
 
+    def __change_log (self, source):
+        last_log = models.Log.objects.filter(
+            source = source.id,
+        ).prefetch_related('sound').order('-date')
+
+        on_air = source.current_sound
+        if on_air == last_log.sound.path:
+            return
+
+        self.log(
+            source = source.id,
+            sound = models.Sound.objects.get(path = on_air),
+            start = tz.make_aware(tz.datetime.now()),
+            comment = 'sound has changed'
+        )
+
+    def monitor (self):
+        """
+        Log changes in the sources, and call dealer.monitor.
+        """
+        self.dealer.monitor()
+        self.__change_log(self.dealer)
+        for source in self.sources:
+            self.__change_log(source)
+
 
 class Monitor:
     """
diff --git a/aircox_programs/admin.py b/aircox_programs/admin.py
index ea428d2..0752043 100755
--- a/aircox_programs/admin.py
+++ b/aircox_programs/admin.py
@@ -90,6 +90,20 @@ class DiffusionAdmin (admin.ModelAdmin):
     list_filter = ('type', 'date', 'program')
     list_editable = ('type', 'date')
 
+    fields = ['type', 'date', 'initial', 'sounds', 'program']
+    readonly_fields = ('duration',)
+
+    def get_form(self, request, obj=None, **kwargs):
+        if obj:
+            if obj.date < tz.make_aware(tz.datetime.now()):
+                self.readonly_fields = list(self.fields)
+                self.readonly_fields.remove('type')
+            elif obj.initial:
+                self.readonly_fields = ['program', 'sounds']
+            else:
+                self.readonly_fields = []
+        return super().get_form(request, obj, **kwargs)
+
     def get_queryset(self, request):
         qs = super(DiffusionAdmin, self).get_queryset(request)
         if '_changelist_filters' in request.GET or \
diff --git a/aircox_programs/models.py b/aircox_programs/models.py
index 5747726..074cfd1 100755
--- a/aircox_programs/models.py
+++ b/aircox_programs/models.py
@@ -396,32 +396,6 @@ class Schedule (models.Model):
         verbose_name_plural = _('Schedules')
 
 
-class Log (models.Model):
-    """
-    Log a played sound start and stop, or a single message
-    """
-    sound = models.ForeignKey(
-        'Sound',
-        help_text = 'Played sound',
-        blank = True, null = True,
-    )
-    stream = models.ForeignKey(
-        'Stream',
-        blank = True, null = True,
-    )
-    start = models.DateTimeField(
-        'start',
-    )
-    stop = models.DateTimeField(
-        'stop',
-        blank = True, null = True,
-    )
-    comment = models.CharField(
-        max_length = 512,
-        blank = True, null = True,
-    )
-
-
 class Station (Nameable):
     """
     A Station regroup one or more programs (stream and normal), and is the top
@@ -607,11 +581,51 @@ class Diffusion (models.Model):
         super(Diffusion, self).save(*args, **kwargs)
 
     def __str__ (self):
-        return self.program.name + ' on ' + str(self.date) \
-               + str(self.type)
+        return self.program.name + ', ' + \
+                self.date.strftime('%Y-%m-%d %H:%M') +\
+                '' # FIXME str(self.type_display)
 
     class Meta:
         verbose_name = _('Diffusion')
         verbose_name_plural = _('Diffusions')
 
 
+class Log (models.Model):
+    """
+    Log a played sound start and stop, or a single message
+    """
+    source = models.CharField(
+        _('source'),
+        max_length = 64,
+        help_text = 'source information',
+        blank = True, null = True,
+    )
+    diffusion = models.ForeignKey(
+        'Diffusion',
+        help_text = _('related diffusion'),
+        blank = True, null = True,
+    )
+    sound = models.ForeignKey(
+        'Sound',
+        help_text = _('played sound'),
+        blank = True, null = True,
+    )
+    date = models.DateTimeField(
+        'date',
+    )
+    comment = models.CharField(
+        max_length = 512,
+        blank = True, null = True,
+    )
+
+    def print (self):
+        print(str(self), ':', self.comment or '')
+        if self.diffusion:
+            print(' - diffusion #' + str(self.diffusion.id))
+        if self.sound:
+            print(' - sound #' + str(self.sound.id), self.sound.path)
+
+    def __str__ (self):
+        return self.date.strftime('%Y-%m-%d %H:%M') + ', ' + self.source
+
+