diff --git a/pysstv/sstv.py b/pysstv/sstv.py
index 1ffe7f3..e69f020 100644
--- a/pysstv/sstv.py
+++ b/pysstv/sstv.py
@@ -4,6 +4,7 @@ from __future__ import division, with_statement
 from six.moves import range
 from six.moves import map
 from six.moves import zip
+from six import PY3
 from math import sin, pi
 from random import random
 from contextlib import closing
@@ -54,7 +55,7 @@ class SSTV(object):
             wav.setnchannels(self.nchannels)
             wav.setsampwidth(self.bits // 8)
             wav.setframerate(self.samples_per_sec)
-            wav.writeframes(data)
+            wav.writeframes(data if PY3 else data.tostring())
 
     def gen_samples(self):
         """generates discrete samples from gen_values()