diff --git a/reactive-midyim.cabal b/reactive-midyim.cabal
--- a/reactive-midyim.cabal
+++ b/reactive-midyim.cabal
@@ -1,12 +1,11 @@
 Name:             reactive-midyim
-Version:          0.4.0.1
+Version:          0.4.1
 License:          BSD3
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
 Maintainer:       Henning Thielemann <haskell@henning-thielemann.de>
 Homepage:         http://www.haskell.org/haskellwiki/Reactive-balsa
 Category:         Sound, Music
-Build-Type:       Simple
 Synopsis:         Process MIDI events via reactive-banana
 Description:
    MIDI is the Musical Instrument Digital Interface,
@@ -45,7 +44,7 @@
 Source-Repository this
   type:     darcs
   location: http://hub.darcs.net/thielema/reactive-midyim/
-  tag:      0.4.0.1
+  tag:      0.4.1
 
 Library
   Build-Depends:
@@ -58,6 +57,7 @@
     utility-ht >=0.0.5 && <0.1,
     containers >=0.2 && <0.6,
     transformers >=0.2 && <0.6,
+    semigroups >=0.1 && <1.0,
     random >=1 && <2,
     base >=4 && <5
 
diff --git a/src/Reactive/Banana/MIDI/Time.hs b/src/Reactive/Banana/MIDI/Time.hs
--- a/src/Reactive/Banana/MIDI/Time.hs
+++ b/src/Reactive/Banana/MIDI/Time.hs
@@ -6,6 +6,7 @@
 
 import Control.Applicative (Const(Const), )
 import Data.Monoid (Monoid, mempty, mappend, )
+import Data.Semigroup (Semigroup, (<>), )
 import Data.Tuple.HT (mapPair, mapSnd, )
 import Data.Ord.HT (comparing, )
 import Data.Eq.HT (equating, )
@@ -56,14 +57,23 @@
 newtype Ticks = Ticks {unTicks :: Integer}
    deriving (Show, Eq, Ord)
 
+instance Semigroup Seconds where
+   Seconds x <> Seconds y = Seconds $ x+y
+
 instance Monoid Seconds where
    mempty = Seconds 0
-   mappend (Seconds x) (Seconds y) = Seconds $ x+y
+   mappend = (<>)
 
+instance Semigroup Ticks where
+   Ticks x <> Ticks y = Ticks $ x+y
+
 instance Monoid Ticks where
    mempty = Ticks 0
-   mappend (Ticks x) (Ticks y) = Ticks $ x+y
+   mappend = (<>)
 
+
+instance (Semigroup a) => Semigroup (T m t a) where
+   x <> y = cons $ decons x <> decons y
 
 instance (Monoid a) => Monoid (T m t a) where
    mempty = cons mempty