diff --git a/midi-alsa.cabal b/midi-alsa.cabal
--- a/midi-alsa.cabal
+++ b/midi-alsa.cabal
@@ -1,5 +1,5 @@
 Name:             midi-alsa
-Version:          0.1.1
+Version:          0.1.2
 License:          BSD3
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -19,12 +19,7 @@
 Build-Type:       Simple
 Source-Repository head
   type:     darcs
-  location: http://code.haskell.org/~thielema/midi-alsa/
-
-Source-Repository this
-  type:     darcs
-  location: http://code.haskell.org/~thielema/midi-alsa/
-  tag:      0.1.1
+  location: http://code.haskell.org/alsa/midi/
 
 Flag splitBase
   description: Choose the new smaller, split-up base package.
@@ -50,3 +45,4 @@
   Hs-Source-Dirs:   src
   Exposed-Modules:
     Sound.MIDI.ALSA
+    Sound.MIDI.ALSA.Check
diff --git a/src/Sound/MIDI/ALSA.hs b/src/Sound/MIDI/ALSA.hs
--- a/src/Sound/MIDI/ALSA.hs
+++ b/src/Sound/MIDI/ALSA.hs
@@ -1,3 +1,9 @@
+{-
+ToDo:
+ALSA events may contain values
+for channel, pitch, velocity, controller, program that are out of bound.
+In this case our conversions yield an error.
+-}
 module Sound.MIDI.ALSA where
 
 import qualified Sound.MIDI.Message.Channel as ChannelMsg
diff --git a/src/Sound/MIDI/ALSA/Check.hs b/src/Sound/MIDI/ALSA/Check.hs
new file mode 100644
--- /dev/null
+++ b/src/Sound/MIDI/ALSA/Check.hs
@@ -0,0 +1,46 @@
+module Sound.MIDI.ALSA.Check where
+
+import qualified Sound.MIDI.ALSA as MALSA
+
+import qualified Sound.ALSA.Sequencer.Event as Event
+
+import Sound.MIDI.Message.Channel (Channel, )
+import Sound.MIDI.Message.Channel.Voice (Controller, )
+
+import Data.Accessor.Basic ((^.), )
+import Data.Maybe.HT (toMaybe, )
+import Control.Monad (guard, )
+
+
+anyController ::
+   Channel -> Event.T -> Maybe (Controller, Int)
+anyController chan e = do
+   -- let Event.TickTime n = Event.timestamp e
+   Event.CtrlEv Event.Controller c <- Just $ Event.body e
+   guard (c ^. MALSA.ctrlChannel  ==  chan)
+   MALSA.Controller cn cv <- Just $ c ^. MALSA.ctrlControllerMode
+   return (cn, cv)
+
+controller :: Channel -> Controller -> Event.T -> Maybe Int
+controller chan ctrl e = do
+   (c,n) <- anyController chan e
+   guard (ctrl==c)
+   return n
+
+pitchBend :: Channel -> Event.T -> Maybe Int
+pitchBend chan e =
+   case Event.body e of
+      Event.CtrlEv Event.PitchBend c ->
+         toMaybe
+            (c ^. MALSA.ctrlChannel == chan)
+            (c ^. MALSA.ctrlValue)
+      _ -> Nothing
+
+channelPressure :: Channel -> Event.T -> Maybe Int
+channelPressure chan e =
+   case Event.body e of
+      Event.CtrlEv Event.ChanPress c ->
+         toMaybe
+            (c ^. MALSA.ctrlChannel == chan)
+            (c ^. MALSA.ctrlValue)
+      _ -> Nothing