diff --git a/README.md b/README.md
index 7a1ef57..87d3212 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,5 @@
 # audio-echo
-Built from Google's NDK sample; plays raw data from microphone in real time
+Built from Google's [NDK sample](https://github.com/android/ndk-samples/tree/main/audio-echo).
+
+Plays raw data from microphone in real time  
+using OpenSL ES.