diff --git a/oregano/Tutorial.md b/oregano/Tutorial.md
index baf28bd..8b17b30 100644
--- a/oregano/Tutorial.md
+++ b/oregano/Tutorial.md
@@ -123,7 +123,11 @@ When the mouse is at the left of the screen, the frequency is 200, when the mous
 
 
 
-
+### Sliders
+
+
+    (add-effect track3 (low-pass-filter resonance 
+                                        (slider : 200 500)))
 
 
 
diff --git a/oregano/instrument.rkt b/oregano/instrument.rkt
index 6a05039..7abc4b2 100644
--- a/oregano/instrument.rkt
+++ b/oregano/instrument.rkt
@@ -1,15 +1,56 @@
 #lang racket
-
-
 (require rsc3 rhs/rhs)
 
 
+;; --- gui stuff
+
+(require (prefix-in gui: racket/gui))
+
+(define frame (new gui:frame% [label "Example"]))
+
+;; parent should be a frame
+(new gui:slider% [parent frame]
+     [label "freq"]
+     [min-value 300]
+     [max-value 1000]
+     [init-value 400]
+     ;; callback receives the slider object and an event object
+     [callback (lambda (s event)
+                   (send-msg (n-set1 1001 "freq" (gui:send s get-value))))])
+
+(gui:send frame show #t)
 
 
-;; simplifies sending messages to server
+;; hypothetical usage
+#;(add-filter track2 (lpf #:resonance .3
+                        #:cutoff (slider 300 800 500)))
+
+(define (slider min-n max-n init)
+  (define bus-id 16)
+  
+  (new gui:slider% [parent frame]
+     [label "amp"]
+     [min-value min-n]
+     [max-value max-n]
+     [init-value init]
+     ;; callback receives the slider object and an event object
+     [callback (lambda (s event)
+                   (send-msg
+                    (c-set1 bus-id (/ (gui:send s get-value) 1000))))])
+
+  
+  (in 1 kr bus-id))
+
+; -------
+
+
+
+
+
+;; simplifies sending osc messages to server
 (define (send-msg msg)
   (with-sc3 (lambda (fd)
-            (send fd msg))))
+              (send fd msg))))
 
 (define current-node-id 1000)
 (define (gen-node-id)
@@ -25,7 +66,7 @@
 (define sin-instrument
   (letc ([bus 0]
          [freq 440])
-        (out bus (mul 0.2 (sin-osc ar freq 0)))))
+        (out bus (mul (slider 100 800 200) (sin-osc ar freq 0)))))
 
 (define saw-instrument
   (letc ([bus 0]
@@ -41,7 +82,7 @@
 
 ;; send synthdefs
 (with-sc3 (lambda (fd)
-                  (send-synth fd "sin-inst" (wave-instrument sin-osc))
+                  (send-synth fd "sin-inst" sin-instrument) ; (wave-instrument sin-osc))
                   (send-synth fd "saw-inst" saw-instrument)))
 
 
@@ -67,10 +108,6 @@
 - to stop/run:
   (send-msg (n-run1 1001 1))
 
--
-
-
-
 |#
 
 ;; ======== test run ===========
@@ -85,3 +122,4 @@
 ; (note-off my-sin)
 
 
+