diff --git a/src/bmixer.rs b/src/bmixer.rs
index cf7989b..c1f5e9a 100644
--- a/src/bmixer.rs
+++ b/src/bmixer.rs
@@ -1,11 +1,11 @@
-use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
 use rodio::{Sample, Source};
 
 use bformat::{Bformat, Bweights};
-use bstream::Bstream;
+use bstream::{self, Bstream, BstreamController};
 
 pub fn bmixer(sample_rate: u32) -> (BstreamMixer, Arc<BmixerController>) {
     let controller = Arc::new(BmixerController {
@@ -54,7 +54,10 @@ impl Iterator for BstreamMixer {
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.controller.has_pending.load(Ordering::SeqCst) {
-            let mut pending = self.controller.pending_streams.lock().expect("Cannot lock pending streams");
+            let mut pending = self.controller
+                .pending_streams
+                .lock()
+                .expect("Cannot lock pending streams");
             self.active_streams.extend(pending.drain(..));
             self.controller.has_pending.store(false, Ordering::SeqCst);
         }
@@ -85,15 +88,20 @@ pub struct BmixerController {
 }
 
 impl BmixerController {
-    pub fn play<I>(&self, input: I, pos: [f32; 3])
+    pub fn play<I>(&self, input: I, pos: [f32; 3]) -> Arc<BstreamController>
     where
-        I: Source<Item = f32> + Send + 'static
+        I: Source<Item = f32> + Send + 'static,
     {
         assert_eq!(input.channels(), 1);
 
-        let bstream = Bstream::new(input, pos);
+        let (bstream, sound_ctl) = bstream::bstream(input, pos);
 
-        self.pending_streams.lock().expect("Cannot lock pending streams").push(bstream);
+        self.pending_streams
+            .lock()
+            .expect("Cannot lock pending streams")
+            .push(bstream);
         self.has_pending.store(true, Ordering::SeqCst);
+
+        sound_ctl
     }
-}
\ No newline at end of file
+}
diff --git a/src/bstream.rs b/src/bstream.rs
index a6cfda8..215ee88 100644
--- a/src/bstream.rs
+++ b/src/bstream.rs
@@ -1,22 +1,34 @@
-use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
 use rodio::Source;
 
 use bformat::{Bformat, Bweights};
 
+pub fn bstream<I: Source<Item = f32> + Send + 'static>(
+    source: I,
+    pos: [f32; 3],
+) -> (Bstream, Arc<BstreamController>) {
+    let controller = Arc::new(BstreamController {
+        commands: Mutex::new(Vec::new()),
+        pending_commands: AtomicBool::new(false),
+        stopped: AtomicBool::new(false),
+    });
+
+    let stream = Bstream {
+        input: Box::new(source),
+        bweights: Bweights::from_position(pos),
+        controller: controller.clone(),
+    };
+
+    (stream, controller)
+}
+
 pub struct Bstream {
     input: Box<Source<Item = f32> + Send>,
     bweights: Bweights,
-}
-
-impl Bstream {
-    pub fn new<I: Source<Item = f32> + Send + 'static>(source: I, pos: [f32; 3]) -> Self {
-        Bstream {
-            input: Box::new(source),
-            bweights: Bweights::from_position(pos),
-        }
-    }
+    controller: Arc<BstreamController>,
 }
 
 impl Source for Bstream {
@@ -46,7 +58,57 @@ impl Iterator for Bstream {
     type Item = Bformat;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let x = self.input.next()?;
-        Some(self.bweights.scale(x))
+        if self.controller.pending_commands.load(Ordering::SeqCst) {
+            let mut commands = self.controller.commands.lock().unwrap();
+            let mut new_pos = None;
+
+            for cmd in commands.drain(..) {
+                match cmd {
+                    Command::SetPos(p) => new_pos = Some(p),
+                    Command::Stop => {
+                        self.controller.stopped.store(true, Ordering::SeqCst);
+                        return None;
+                    }
+                }
+            }
+
+            if let Some(pos) = new_pos {
+                self.bweights = Bweights::from_position(pos);
+            }
+
+            self.controller
+                .pending_commands
+                .store(false, Ordering::SeqCst);
+        }
+        match self.input.next() {
+            Some(x) => Some(self.bweights.scale(x)),
+            None => {
+                self.controller.stopped.store(true, Ordering::SeqCst);
+                None
+            }
+        }
+    }
+}
+
+enum Command {
+    SetPos([f32; 3]),
+    Stop,
+}
+
+pub struct BstreamController {
+    commands: Mutex<Vec<Command>>,
+    pending_commands: AtomicBool,
+    stopped: AtomicBool,
+}
+
+impl BstreamController {
+    pub fn set_position(&self, pos: [f32; 3]) {
+        self.commands.lock().unwrap().push(Command::SetPos(pos));
+        self.pending_commands.store(true, Ordering::SeqCst);
+    }
+
+    pub fn stop(&self) {
+        self.commands.lock().unwrap().push(Command::Stop);
+        self.pending_commands.store(true, Ordering::SeqCst);
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 0c3f14c..dc30fa2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,8 +2,8 @@ extern crate cpal;
 pub extern crate rodio;
 
 mod bformat;
-mod bstream;
 mod bmixer;
+mod bstream;
 mod renderer;
 
 use std::sync::Arc;
@@ -37,7 +37,7 @@ impl AmbisonicBuilder {
         }
     }
 
-    pub fn build(self) -> Engine {
+    pub fn build(self) -> Ambisonic {
         let device = self.device
             .unwrap_or_else(|| rodio::default_output_device().unwrap());
         let sink = rodio::Sink::new(&device);
@@ -47,14 +47,11 @@ impl AmbisonicBuilder {
 
         sink.append(output);
 
-        Engine {
-            sink,
-            controller,
-        }
+        Ambisonic { sink, controller }
     }
 }
 
-pub struct Engine {
+pub struct Ambisonic {
     sink: rodio::Sink,
     controller: Arc<BmixerController>,
 }
@@ -70,13 +67,18 @@ mod tests {
         let engine = AmbisonicBuilder::new().build();
 
         let source = rodio::source::SineWave::new(440);
-        engine.controller.play(source, [1.0, 0.0, 0.0]);
+        let first = engine.controller.play(source, [1.0, 0.0, 0.0]);
 
         sleep(Duration::from_millis(1000));
 
         let source = rodio::source::SineWave::new(330);
-        engine.controller.play(source, [-1.0, 0.0, 0.0]);
+        let second = engine.controller.play(source, [-1.0, 0.0, 0.0]);
 
-        sleep(Duration::from_millis(2000));
+        sleep(Duration::from_millis(1000));
+
+        first.stop();
+        second.set_position([0.0, 1.0, 0.0]);
+
+        sleep(Duration::from_millis(1000));
     }
 }