diff --git a/deepspeech/frontend/audio.py b/deepspeech/frontend/audio.py
index 4488f5f2e1f961ddb47b6d4669b1924c81b570df..ffdcd4b3a5f3b3e7bd8c3725fa8199c3e89e40c4 100644
--- a/deepspeech/frontend/audio.py
+++ b/deepspeech/frontend/audio.py
@@ -351,7 +351,9 @@ class AudioSegment(object):
         tfm.set_globals(multithread=False)
         tfm.speed(speed_rate)
         self._samples = tfm.build_array(
-            input_array=self._samples, sample_rate_in=self._sample_rate).copy()
+            input_array=self._samples,
+            sample_rate_in=self._sample_rate).squeeze(-1).astype(
+                np.float32).copy()
 
     def normalize(self, target_db=-20, max_gain_db=300.0):
         """Normalize audio to be of the desired RMS value in decibels.
diff --git a/examples/librispeech/s0/conf/augmentation.json b/examples/librispeech/s0/conf/augmentation.json
index a1a759e67f3a118b6754a60aead069742ede6ecc..5635d9c84c48938f746dcdffd1a16eff9ac8b98c 100644
--- a/examples/librispeech/s0/conf/augmentation.json
+++ b/examples/librispeech/s0/conf/augmentation.json
@@ -1,4 +1,13 @@
 [
+  {
+    "type": "speed",
+    "params": {
+      "min_speed_rate": 0.9,
+      "max_speed_rate": 1.1,
+      "num_rates": 3
+    },
+    "prob": 0.0
+  },
   {
     "type": "shift",
     "params": {
diff --git a/examples/tiny/s1/conf/augmentation.json b/examples/tiny/s1/conf/augmentation.json
index 1987ad4245dcf5542f1e22a545c36899659acef9..f26c282e7ddb3329923d4d10b0d392a254a216fe 100644
--- a/examples/tiny/s1/conf/augmentation.json
+++ b/examples/tiny/s1/conf/augmentation.json
@@ -6,7 +6,7 @@
       "max_speed_rate": 1.1,
       "num_rates": 3
     },
-    "prob": 0.0
+    "prob": 1.0
   },
   {
     "type": "shift",