diff --git a/audio/LICENSE b/audio/LICENSE
index 022f989..a4888a5 100644
--- a/audio/LICENSE
+++ b/audio/LICENSE
@@ -1,26 +1,28 @@
 Licenses for the sound files
 =============================
 
-*boost.mp3*
+*boost.ogg*
 
 Created by IFartInUrGeneralDirection and distributed under
 Creative Commons 3.0 Attribution 3.0 Unported license.
 
-*crash.mp3*
+*crash.ogg*
 Created by qubodup and is published into Public Domain.
 
-*wind.mp3*
+*wind.ogg*
 Created by kangaroovindaloo and distributed under
 Creative Commons 3.0 Attribution 3.0 Unported license.
 
 This SFX is further cutted and adjusted by Licson.
 
-*bg.mp3*
+*bg.ogg*
 Created by mu6k and is released into Public Domain.
 
 Further adjusted by Licson.
 
-*destroyed.mp3*
+*destroyed.ogg*
 Created by beman87 and is distributed under Creative Commons Attribution 3.0 Unported license.
 
-This SFX is further adjusted by Licson.
\ No newline at end of file
+This SFX is further adjusted by Licson.
+
+All sound files converted to OGG Vorbis by baleboy using VLC Media Player.
\ No newline at end of file
diff --git a/audio/bg.mp3 b/audio/bg.mp3
deleted file mode 100644
index 1cc566b..0000000
Binary files a/audio/bg.mp3 and /dev/null differ
diff --git a/audio/bg.ogg b/audio/bg.ogg
new file mode 100644
index 0000000..bcb0d27
Binary files /dev/null and b/audio/bg.ogg differ
diff --git a/audio/boost.mp3 b/audio/boost.mp3
deleted file mode 100644
index 5a83c8c..0000000
Binary files a/audio/boost.mp3 and /dev/null differ
diff --git a/audio/boost.ogg b/audio/boost.ogg
new file mode 100644
index 0000000..bcbf20c
Binary files /dev/null and b/audio/boost.ogg differ
diff --git a/audio/crash.mp3 b/audio/crash.mp3
deleted file mode 100644
index 0386646..0000000
Binary files a/audio/crash.mp3 and /dev/null differ
diff --git a/audio/crash.ogg b/audio/crash.ogg
new file mode 100644
index 0000000..8ff0301
Binary files /dev/null and b/audio/crash.ogg differ
diff --git a/audio/destroyed.mp3 b/audio/destroyed.mp3
deleted file mode 100644
index 98d2963..0000000
Binary files a/audio/destroyed.mp3 and /dev/null differ
diff --git a/audio/destroyed.ogg b/audio/destroyed.ogg
new file mode 100644
index 0000000..4918b1a
Binary files /dev/null and b/audio/destroyed.ogg differ
diff --git a/audio/wind.mp3 b/audio/wind.mp3
deleted file mode 100644
index 38cce00..0000000
Binary files a/audio/wind.mp3 and /dev/null differ
diff --git a/audio/wind.ogg b/audio/wind.ogg
new file mode 100644
index 0000000..812077e
Binary files /dev/null and b/audio/wind.ogg differ
diff --git a/bkcore/hexgl/tracks/Cityscape.js b/bkcore/hexgl/tracks/Cityscape.js
index ae7095a..585ca4b 100644
--- a/bkcore/hexgl/tracks/Cityscape.js
+++ b/bkcore/hexgl/tracks/Cityscape.js
@@ -86,27 +86,27 @@ bkcore.hexgl.tracks.Cityscape = {
 				},
 				sounds: {
 					bg: {
-						src: 'audio/bg.mp3',
+						src: 'audio/bg.ogg',
 						loop: true,
 						usePanner: false
 					},
 					crash: {
-						src: 'audio/crash.mp3',
+						src: 'audio/crash.ogg',
 						loop: false,
 						usePanner: true
 					},
 					destroyed: {
-						src: 'audio/destroyed.mp3',
+						src: 'audio/destroyed.ogg',
 						loop: false,
 						usePanner: false
 					},
 					boost: {
-						src: 'audio/boost.mp3',
+						src: 'audio/boost.ogg',
 						loop: false,
 						usePanner: true
 					},
 					wind: {
-						src: 'audio/wind.mp3',
+						src: 'audio/wind.ogg',
 						loop: true,
 						usePanner: true
 					}
@@ -170,23 +170,23 @@ bkcore.hexgl.tracks.Cityscape = {
 				},
 				sounds: {
 					bg: {
-						src: 'audio/bg.mp3',
+						src: 'audio/bg.ogg',
 						loop: true
 					},
 					crash: {
-						src: 'audio/crash.mp3',
+						src: 'audio/crash.ogg',
 						loop: false
 					},
 					destroyed: {
-						src: 'audio/destroyed.mp3',
+						src: 'audio/destroyed.ogg',
 						loop: false
 					},
 					boost: {
-						src: 'audio/boost.mp3',
+						src: 'audio/boost.ogg',
 						loop: false
 					},
 					wind: {
-						src: 'audio/wind.mp3',
+						src: 'audio/wind.ogg',
 						loop: true
 					}
 				}