add test-model notebook

notebooks/test-mel.ipynb

@@ -44,6 +44,14 @@
     "mel = Mel()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "b2178c3f",
+   "metadata": {},
+   "source": [
+    "### Transform slice of audio to Mel spectrogram"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 8,
@@ -107,6 +115,14 @@
     "image.width, image.height"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "fe112fef",
+   "metadata": {},
+   "source": [
+    "### Transform Mel spectrogram back to audio"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 13,