diff --git a/README.md b/README.md
index a4ee02a..a8dee5f 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,11 @@
 # Scoobidules
 
 A collection of snippets, patches, classes and hybrid SuperCollider bidules
+
+## Where are files located?
+
+As far as I know, the extensions folder for SuperCollider is necessarily located at `~/.local/share/SuperCollider/Extensions`. Classes must be copied in there.
+
+SynthDefs can be placed in `~/.local/share/SuperCollider/synthdefs` to [load them on server start].
+
+The `startup.scd` file must be placed in `~/.config/SuperCollider`.
diff --git a/extensions/Track/classes/mixer.sc b/extensions/Track/classes/mixer.sc
index c41a9d6..262855f 100644
--- a/extensions/Track/classes/mixer.sc
+++ b/extensions/Track/classes/mixer.sc
@@ -1,4 +1,4 @@
-// bidule holding a master track receiving from a bus, and a collection 
+// bidule holding a master track receiving from a bus, and a collection
 // of Tracks
 Mixer : Fadable {
 	var name, master, masterBus, tracks, track, level;
diff --git a/extensions/Track/classes/track.sc b/extensions/Track/classes/track.sc
index e5760a2..6b88a12 100644
--- a/extensions/Track/classes/track.sc
+++ b/extensions/Track/classes/track.sc
@@ -3,7 +3,7 @@ Track : Fadable {
 	/*
 		TODO: don't instanciate if name already exist ?
 	*/
-	var out, <group, <groupFX, <groupSynth, <track, busTrack, busFX, level;
+	var out, <group, <groupFX, <groupSynth, <track, trackFX, busTrack, busFX, level;
 
 	*new {
 		|out|
@@ -38,8 +38,9 @@ Track : Fadable {
 		group = Group.new(Server.default);
 		groupSynth = Group.head(group);
 		groupFX = Group.after(groupSynth);
+		trackFX = Dictionary();
 		track = Synth(
-			\fader, 
+			\fader,
 			[
 				in: busTrack.index,
 				fxIn: busFX.index,
@@ -58,6 +59,13 @@ Track : Fadable {
 		^busFX.index;
 	}
 
+	appendFX {
+		|fxName, params=#[]|
+		var fx;
+		fx = Synth.new(fxName, params ++ [in: this.in, out: this.inFX], this.groupFX);
+		trackFX.put(fxName, fx);
+	}
+
 	// printOn {
 	// 	|stream|
 	// }