diff --git a/Cargo.toml b/Cargo.toml
index dfed4c9..e9fa5a4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,7 +12,7 @@ keywords = ["audio", "sound"]
 [dependencies]
 libc = "*"
 lazy_static = "0.1"
-winapi = "0.2.3"
+winapi = "0.2.4"
 ole32-sys = "0.1"
 
 [target.i686-unknown-linux-gnu.dependencies.alsa-sys]
diff --git a/src/wasapi/mod.rs b/src/wasapi/mod.rs
index 4394d76..4d5ae68 100644
--- a/src/wasapi/mod.rs
+++ b/src/wasapi/mod.rs
@@ -18,26 +18,6 @@ pub use self::voice::{Voice, Buffer};
 
 pub type SupportedFormatsIterator = OptionIntoIter<Format>;
 
-// TODO: these constants should be moved to winapi
-const SPEAKER_FRONT_LEFT: winapi::DWORD = 0x1;
-const SPEAKER_FRONT_RIGHT: winapi::DWORD = 0x2;
-const SPEAKER_FRONT_CENTER: winapi::DWORD = 0x4;
-const SPEAKER_LOW_FREQUENCY: winapi::DWORD = 0x8;
-const SPEAKER_BACK_LEFT: winapi::DWORD = 0x10;
-const SPEAKER_BACK_RIGHT: winapi::DWORD = 0x20;
-const SPEAKER_FRONT_LEFT_OF_CENTER: winapi::DWORD = 0x40;
-const SPEAKER_FRONT_RIGHT_OF_CENTER: winapi::DWORD = 0x80;
-const SPEAKER_BACK_CENTER: winapi::DWORD = 0x100;
-const SPEAKER_SIDE_LEFT: winapi::DWORD = 0x200;
-const SPEAKER_SIDE_RIGHT: winapi::DWORD = 0x400;
-const SPEAKER_TOP_CENTER: winapi::DWORD = 0x800;
-const SPEAKER_TOP_FRONT_LEFT: winapi::DWORD = 0x1000;
-const SPEAKER_TOP_FRONT_CENTER: winapi::DWORD = 0x2000;
-const SPEAKER_TOP_FRONT_RIGHT: winapi::DWORD = 0x4000;
-const SPEAKER_TOP_BACK_LEFT: winapi::DWORD = 0x8000;
-const SPEAKER_TOP_BACK_CENTER: winapi::DWORD = 0x10000;
-const SPEAKER_TOP_BACK_RIGHT: winapi::DWORD = 0x20000;
-
 mod com;
 mod enumerate;
 mod voice;
@@ -153,24 +133,24 @@ impl Endpoint {
                             let mut channels = Vec::new();
 
                             let mask = (*format_ptr).dwChannelMask;
-                            if (mask & SPEAKER_FRONT_LEFT) != 0 { channels.push(ChannelPosition::FrontLeft); }
-                            if (mask & SPEAKER_FRONT_RIGHT) != 0 { channels.push(ChannelPosition::FrontRight); }
-                            if (mask & SPEAKER_FRONT_CENTER) != 0 { channels.push(ChannelPosition::FrontCenter); }
-                            if (mask & SPEAKER_LOW_FREQUENCY) != 0 { channels.push(ChannelPosition::LowFrequency); }
-                            if (mask & SPEAKER_BACK_LEFT) != 0 { channels.push(ChannelPosition::BackLeft); }
-                            if (mask & SPEAKER_BACK_RIGHT) != 0 { channels.push(ChannelPosition::BackRight); }
-                            if (mask & SPEAKER_FRONT_LEFT_OF_CENTER) != 0 { channels.push(ChannelPosition::FrontLeftOfCenter); }
-                            if (mask & SPEAKER_FRONT_RIGHT_OF_CENTER) != 0 { channels.push(ChannelPosition::FrontRightOfCenter); }
-                            if (mask & SPEAKER_BACK_CENTER) != 0 { channels.push(ChannelPosition::BackCenter); }
-                            if (mask & SPEAKER_SIDE_LEFT) != 0 { channels.push(ChannelPosition::SideLeft); }
-                            if (mask & SPEAKER_SIDE_RIGHT) != 0 { channels.push(ChannelPosition::SideRight); }
-                            if (mask & SPEAKER_TOP_CENTER) != 0 { channels.push(ChannelPosition::TopCenter); }
-                            if (mask & SPEAKER_TOP_FRONT_LEFT) != 0 { channels.push(ChannelPosition::TopFrontLeft); }
-                            if (mask & SPEAKER_TOP_FRONT_CENTER) != 0 { channels.push(ChannelPosition::TopFrontCenter); }
-                            if (mask & SPEAKER_TOP_FRONT_RIGHT) != 0 { channels.push(ChannelPosition::TopFrontRight); }
-                            if (mask & SPEAKER_TOP_BACK_LEFT) != 0 { channels.push(ChannelPosition::TopBackLeft); }
-                            if (mask & SPEAKER_TOP_BACK_CENTER) != 0 { channels.push(ChannelPosition::TopBackCenter); }
-                            if (mask & SPEAKER_TOP_BACK_RIGHT) != 0 { channels.push(ChannelPosition::TopBackRight); }
+                            if (mask & winapi::SPEAKER_FRONT_LEFT) != 0 { channels.push(ChannelPosition::FrontLeft); }
+                            if (mask & winapi::SPEAKER_FRONT_RIGHT) != 0 { channels.push(ChannelPosition::FrontRight); }
+                            if (mask & winapi::SPEAKER_FRONT_CENTER) != 0 { channels.push(ChannelPosition::FrontCenter); }
+                            if (mask & winapi::SPEAKER_LOW_FREQUENCY) != 0 { channels.push(ChannelPosition::LowFrequency); }
+                            if (mask & winapi::SPEAKER_BACK_LEFT) != 0 { channels.push(ChannelPosition::BackLeft); }
+                            if (mask & winapi::SPEAKER_BACK_RIGHT) != 0 { channels.push(ChannelPosition::BackRight); }
+                            if (mask & winapi::SPEAKER_FRONT_LEFT_OF_CENTER) != 0 { channels.push(ChannelPosition::FrontLeftOfCenter); }
+                            if (mask & winapi::SPEAKER_FRONT_RIGHT_OF_CENTER) != 0 { channels.push(ChannelPosition::FrontRightOfCenter); }
+                            if (mask & winapi::SPEAKER_BACK_CENTER) != 0 { channels.push(ChannelPosition::BackCenter); }
+                            if (mask & winapi::SPEAKER_SIDE_LEFT) != 0 { channels.push(ChannelPosition::SideLeft); }
+                            if (mask & winapi::SPEAKER_SIDE_RIGHT) != 0 { channels.push(ChannelPosition::SideRight); }
+                            if (mask & winapi::SPEAKER_TOP_CENTER) != 0 { channels.push(ChannelPosition::TopCenter); }
+                            if (mask & winapi::SPEAKER_TOP_FRONT_LEFT) != 0 { channels.push(ChannelPosition::TopFrontLeft); }
+                            if (mask & winapi::SPEAKER_TOP_FRONT_CENTER) != 0 { channels.push(ChannelPosition::TopFrontCenter); }
+                            if (mask & winapi::SPEAKER_TOP_FRONT_RIGHT) != 0 { channels.push(ChannelPosition::TopFrontRight); }
+                            if (mask & winapi::SPEAKER_TOP_BACK_LEFT) != 0 { channels.push(ChannelPosition::TopBackLeft); }
+                            if (mask & winapi::SPEAKER_TOP_BACK_CENTER) != 0 { channels.push(ChannelPosition::TopBackCenter); }
+                            if (mask & winapi::SPEAKER_TOP_BACK_RIGHT) != 0 { channels.push(ChannelPosition::TopBackRight); }
 
                             assert_eq!((*format_ptr).Format.nChannels as usize, channels.len());
                             channels
diff --git a/src/wasapi/voice.rs b/src/wasapi/voice.rs
index 9e0b065..7b9f205 100644
--- a/src/wasapi/voice.rs
+++ b/src/wasapi/voice.rs
@@ -73,24 +73,24 @@ impl Voice {
                         let mut mask = 0;
                         for &channel in format.channels.iter() {
                             let raw_value = match channel {
-                                ChannelPosition::FrontLeft => super::SPEAKER_FRONT_LEFT,
-                                ChannelPosition::FrontRight => super::SPEAKER_FRONT_RIGHT,
-                                ChannelPosition::FrontCenter => super::SPEAKER_FRONT_CENTER,
-                                ChannelPosition::LowFrequency => super::SPEAKER_LOW_FREQUENCY,
-                                ChannelPosition::BackLeft => super::SPEAKER_BACK_LEFT,
-                                ChannelPosition::BackRight => super::SPEAKER_BACK_RIGHT,
-                                ChannelPosition::FrontLeftOfCenter => super::SPEAKER_FRONT_LEFT_OF_CENTER,
-                                ChannelPosition::FrontRightOfCenter => super::SPEAKER_FRONT_RIGHT_OF_CENTER,
-                                ChannelPosition::BackCenter => super::SPEAKER_BACK_CENTER,
-                                ChannelPosition::SideLeft => super::SPEAKER_SIDE_LEFT,
-                                ChannelPosition::SideRight => super::SPEAKER_SIDE_RIGHT,
-                                ChannelPosition::TopCenter => super::SPEAKER_TOP_CENTER,
-                                ChannelPosition::TopFrontLeft => super::SPEAKER_TOP_FRONT_LEFT,
-                                ChannelPosition::TopFrontCenter => super::SPEAKER_TOP_FRONT_CENTER,
-                                ChannelPosition::TopFrontRight => super::SPEAKER_TOP_FRONT_RIGHT,
-                                ChannelPosition::TopBackLeft => super::SPEAKER_TOP_BACK_LEFT,
-                                ChannelPosition::TopBackCenter => super::SPEAKER_TOP_BACK_CENTER,
-                                ChannelPosition::TopBackRight => super::SPEAKER_TOP_BACK_RIGHT,
+                                ChannelPosition::FrontLeft => winapi::SPEAKER_FRONT_LEFT,
+                                ChannelPosition::FrontRight => winapi::SPEAKER_FRONT_RIGHT,
+                                ChannelPosition::FrontCenter => winapi::SPEAKER_FRONT_CENTER,
+                                ChannelPosition::LowFrequency => winapi::SPEAKER_LOW_FREQUENCY,
+                                ChannelPosition::BackLeft => winapi::SPEAKER_BACK_LEFT,
+                                ChannelPosition::BackRight => winapi::SPEAKER_BACK_RIGHT,
+                                ChannelPosition::FrontLeftOfCenter => winapi::SPEAKER_FRONT_LEFT_OF_CENTER,
+                                ChannelPosition::FrontRightOfCenter => winapi::SPEAKER_FRONT_RIGHT_OF_CENTER,
+                                ChannelPosition::BackCenter => winapi::SPEAKER_BACK_CENTER,
+                                ChannelPosition::SideLeft => winapi::SPEAKER_SIDE_LEFT,
+                                ChannelPosition::SideRight => winapi::SPEAKER_SIDE_RIGHT,
+                                ChannelPosition::TopCenter => winapi::SPEAKER_TOP_CENTER,
+                                ChannelPosition::TopFrontLeft => winapi::SPEAKER_TOP_FRONT_LEFT,
+                                ChannelPosition::TopFrontCenter => winapi::SPEAKER_TOP_FRONT_CENTER,
+                                ChannelPosition::TopFrontRight => winapi::SPEAKER_TOP_FRONT_RIGHT,
+                                ChannelPosition::TopBackLeft => winapi::SPEAKER_TOP_BACK_LEFT,
+                                ChannelPosition::TopBackCenter => winapi::SPEAKER_TOP_BACK_CENTER,
+                                ChannelPosition::TopBackRight => winapi::SPEAKER_TOP_BACK_RIGHT,
                             };
 
                             // channels must be in the right order