diff --git a/adafruit_rtttl.py b/adafruit_rtttl.py
index c2087be..848be44 100644
--- a/adafruit_rtttl.py
+++ b/adafruit_rtttl.py
@@ -19,17 +19,21 @@
 import pwmio
 
 AUDIOIO_AVAILABLE = False
+WAVEFORM_AVAILABLE = False
 try:
     import audioio
-    from adafruit_waveform import sine
 
     AUDIOIO_AVAILABLE = True
+    from adafruit_waveform import sine
+
+    WAVEFORM_AVAILABLE = True
     try:
         import audiocore
     except ImportError:
         audiocore = audioio
-except ImportError:
-    pass
+except ImportError as e:
+    if not WAVEFORM_AVAILABLE:
+        raise e
 
 try:
     from typing import Optional, Union, Tuple, List
diff --git a/docs/conf.py b/docs/conf.py
index 7b280e5..954bde4 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -20,7 +20,7 @@
     "sphinx.ext.viewcode",
 ]
 
-autodoc_mock_imports = ["pulseio", "pwmio", "audioio"]
+autodoc_mock_imports = ["pulseio", "pwmio", "audioio", "adafruit_waveform"]
 
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3.4", None),