diff --git a/auto-calib.sh b/auto-calib.sh
index fc651f7..af47cc2 100755
--- a/auto-calib.sh
+++ b/auto-calib.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
 killall -q aplay arecord
 ./calib.py send &
+SENDER_PID=$!
 ./calib.py recv
-killall -q aplay arecord
\ No newline at end of file
+
+kill -INT $SENDER_PID
diff --git a/calib.py b/calib.py
index 1d8b22d..53446b7 100755
--- a/calib.py
+++ b/calib.py
@@ -12,35 +12,39 @@ sig_dump = common.dumps(sig)
 
 
 def send():
-    p = wave.play('-', stdin=wave.sp.PIPE)
-    while True:
-        try:
-            p.stdin.write(sig_dump)
-        except IOError:
-            return
-
+    p = wave.play('-', stdin=wave.sp.PIPE, stderr=open('/dev/null'))
+    try:
+        while True:
+            try:
+                p.stdin.write(sig_dump)
+            except IOError:
+                return
+    except KeyboardInterrupt:
+        p.kill()
 
 def recv():
-    out = wave.record('-', stdout=wave.sp.PIPE).stdout
-    while True:
-        data = out.read(len(sig_dump))
-        if len(data) < len(sig_dump):
-            return
-        try:
-            x = common.loads(data)
-        except common.SaturationError as e:
-            print('saturation: {}'.format(e))
-            continue
-        x = x - np.mean(x)
-
-        c = np.abs(np.dot(x, sig)) / (np.sqrt(0.5 * len(x)) * sigproc.norm(x))
-        z = np.dot(x, sig.conj()) / (0.5 * len(x))
-        amp = np.abs(z)
-        phase = np.angle(z)
-        peak = np.max(np.abs(x))
-        print('coherence={:.3f} amp={:.3f} phase={:.1f} peak={:.3f}'.format(
-              c, amp, phase * 180 / np.pi, peak))
+    p = wave.record('-', stdout=wave.sp.PIPE)
+    try:
+        while True:
+            data = p.stdout.read(len(sig_dump))
+            if len(data) < len(sig_dump):
+                return
+            try:
+                x = common.loads(data)
+            except common.SaturationError as e:
+                print('saturation: {}'.format(e))
+                continue
+            x = x - np.mean(x)
 
+            c = np.abs(np.dot(x, sig)) / (np.sqrt(0.5 * len(x)) * sigproc.norm(x))
+            z = np.dot(x, sig.conj()) / (0.5 * len(x))
+            amp = np.abs(z)
+            phase = np.angle(z)
+            peak = np.max(np.abs(x))
+            print('coherence={:.3f} amp={:.3f} phase={:.1f} peak={:.3f}'.format(
+                  c, amp, phase * 180 / np.pi, peak))
+    except KeyboardInterrupt:
+        p.kill()
 
 if __name__ == '__main__':
     import argparse