diff --git a/src/conversions/sample_rate.rs b/src/conversions/sample_rate.rs
index 2fd26c5..36aa5a5 100644
--- a/src/conversions/sample_rate.rs
+++ b/src/conversions/sample_rate.rs
@@ -259,6 +259,12 @@ mod test {
     use cpal::SampleRate;
     use quickcheck::quickcheck;
 
+    // TODO: Remove once cpal 0.12.2 is released and the dependency is updated
+    //  (cpal#483 implemented ops::Mul on SampleRate)
+    const fn multiply_rate(r: SampleRate, k: u32) -> SampleRate {
+        SampleRate(k * r.0)
+    }
+
     quickcheck! {
         /// Check that resampling an empty input produces no output.
         fn empty(from: u32, to: u32, n: u16) -> () {
@@ -289,9 +295,9 @@ mod test {
         /// Check that dividing the sample rate by k (integer) is the same as
         ///   dropping a sample from each channel.
         fn divide_sample_rate(to: u32, k: u32, input: Vec<u16>, n: u16) -> () {
-            if k == 0 || n == 0 || to.checked_mul(k).is_none() { return; }
             let to = if to == 0 { return; } else { SampleRate(to) };
-            let from = to * k;
+            let from = multiply_rate(to, k);
+            if k == 0 || n == 0 { return; }
 
             // Truncate the input, so it contains an integer number of frames.
             let input = {
@@ -313,9 +319,9 @@ mod test {
         /// Check that, after multiplying the sample rate by k, every k-th
         ///  sample in the output matches exactly with the input.
         fn multiply_sample_rate(from: u32, k: u32, input: Vec<u16>, n: u16) -> () {
-            if k == 0 || n == 0 || from.checked_mul(k).is_none() { return; }
             let from = if from == 0 { return; } else { SampleRate(from) };
-            let to = from * k;
+            let to = multiply_rate(from, k);
+            if k == 0 || n == 0 { return; }
 
             // Truncate the input, so it contains an integer number of frames.
             let input = {
diff --git a/src/dynamic_mixer.rs b/src/dynamic_mixer.rs
index da5a493..61c13ee 100644
--- a/src/dynamic_mixer.rs
+++ b/src/dynamic_mixer.rs
@@ -1,4 +1,5 @@
 //! Mixer that plays multiple sounds at the same time.
+
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
@@ -27,6 +28,8 @@ where
         current_sources: Vec::with_capacity(16),
         input: input.clone(),
         sample_count: 0,
+        still_pending: vec![],
+        still_current: vec![],
     };
 
     (input, output)
@@ -51,8 +54,10 @@ where
         T: Source<Item = S> + Send + 'static,
     {
         let uniform_source = UniformSourceIterator::new(source, self.channels, self.sample_rate);
-        let mut pending = self.pending_sources.lock().unwrap();
-        pending.push(Box::new(uniform_source) as Box<_>);
+        self.pending_sources
+            .lock()
+            .unwrap()
+            .push(Box::new(uniform_source) as Box<_>);
         self.has_pending.store(true, Ordering::SeqCst); // TODO: can we relax this ordering?
     }
 }
@@ -67,6 +72,12 @@ pub struct MixerSource<S> {
 
     // The number of samples produced so far.
     sample_count: usize,
+
+    // A temporary vec used in start_pending_sources.
+    still_pending: Vec<Box<dyn Source<Item = S> + Send>>,
+
+    // A temporary vec used in sum_current_sources.
+    still_current: Vec<Box<dyn Source<Item = S> + Send>>,
 }
 
 impl<S> Source for MixerSource<S>
@@ -168,16 +179,18 @@ where
     // in-step with the modulo of the samples produced so far. Otherwise, the
     // sound will play on the wrong channels, e.g. left / right will be reversed.
     fn start_pending_sources(&mut self) {
-        let mut pending = self.input.pending_sources.lock().unwrap();
-        let mut i = 0;
-        while i < pending.len() {
-            let in_step = self.sample_count % pending[i].channels() as usize == 0;
+        let mut pending = self.input.pending_sources.lock().unwrap(); // TODO: relax ordering?
+
+        for source in pending.drain(..) {
+            let in_step = self.sample_count % source.channels() as usize == 0;
+
             if in_step {
-                self.current_sources.push(pending.swap_remove(i));
+                self.current_sources.push(source);
             } else {
-                i += 1;
+                self.still_pending.push(source);
             }
         }
+        std::mem::swap(&mut self.still_pending, &mut pending);
 
         let has_pending = !pending.is_empty();
         self.input.has_pending.store(has_pending, Ordering::SeqCst); // TODO: relax ordering?
@@ -185,15 +198,15 @@ where
 
     fn sum_current_sources(&mut self) -> S {
         let mut sum = S::zero_value();
-        let mut i = 0;
-        while i < self.current_sources.len() {
-            if let Some(value) = self.current_sources[i].next() {
+
+        for mut source in self.current_sources.drain(..) {
+            if let Some(value) = source.next() {
                 sum = sum.saturating_add(value);
-                i += 1;
-            } else {
-                self.current_sources.swap_remove(i);
+                self.still_current.push(source);
             }
         }
+        std::mem::swap(&mut self.still_current, &mut self.current_sources);
+
         sum
     }
 }
diff --git a/src/source/mod.rs b/src/source/mod.rs
index 33ca934..4802e53 100644
--- a/src/source/mod.rs
+++ b/src/source/mod.rs
@@ -145,6 +145,7 @@ pub use self::noise::{pink, white, PinkNoise, WhiteNoise};
 /// In order to properly handle this situation, the `current_frame_len()` method should return
 /// the number of samples that remain in the iterator before the samples rate and number of
 /// channels can potentially change.
+///
 pub trait Source: Iterator
 where
     Self::Item: Sample,
diff --git a/src/source/uniform.rs b/src/source/uniform.rs
index 7d25a8b..b9d146d 100644
--- a/src/source/uniform.rs
+++ b/src/source/uniform.rs
@@ -41,9 +41,9 @@ where
         target_sample_rate: u32,
     ) -> UniformSourceIterator<I, D> {
         let total_duration = input.total_duration();
-        let input = Self::bootstrap(input, target_channels, target_sample_rate);
+        let input = UniformSourceIterator::bootstrap(input, target_channels, target_sample_rate);
 
-        Self {
+        UniformSourceIterator {
             inner: Some(input),
             target_channels,
             target_sample_rate,
@@ -102,7 +102,8 @@ where
             .into_inner()
             .iter;
 
-        let mut input = Self::bootstrap(input, self.target_channels, self.target_sample_rate);
+        let mut input =
+            UniformSourceIterator::bootstrap(input, self.target_channels, self.target_sample_rate);
 
         let value = input.next();
         self.inner = Some(input);
diff --git a/src/spatial_sink.rs b/src/spatial_sink.rs
index 8f2e2e8..bddd679 100644
--- a/src/spatial_sink.rs
+++ b/src/spatial_sink.rs
@@ -96,10 +96,20 @@ impl SpatialSink {
         self.sink.set_volume(value);
     }
 
-    /// Gets the speed of the sound.
+    /// Changes the play speed of the sound. Does not adjust the samples, only the playback speed.
     ///
-    /// The value `1.0` is the "normal" speed (unfiltered input). Any value other than `1.0` will
-    /// change the play speed of the sound.
+    /// # Note:
+    /// 1. **Increasing the speed will increase the pitch by the same factor**
+    /// - If you set the speed to 0.5 this will halve the frequency of the sound
+    ///   lowering its pitch.
+    /// - If you set the speed to 2 the frequency will double raising the
+    ///   pitch of the sound.
+    /// 2. **Change in the speed affect the total duration inversely**
+    /// - If you set the speed to 0.5, the total duration will be twice as long.
+    /// - If you set the speed to 2 the total duration will be halve of what it
+    ///   was.
+    ///
+    /// See [`Speed`] for details
     #[inline]
     pub fn speed(&self) -> f32 {
         self.sink.speed()
@@ -138,6 +148,14 @@ impl SpatialSink {
         self.sink.is_paused()
     }
 
+    /// Removes all currently loaded `Source`s from the `SpatialSink` and pauses it.
+    ///
+    /// See `pause()` for information about pausing a `Sink`.
+    #[inline]
+    pub fn clear(&self) {
+        self.sink.clear();
+    }
+
     /// Stops the sink by emptying the queue.
     #[inline]
     pub fn stop(&self) {
@@ -163,8 +181,43 @@ impl SpatialSink {
     }
 
     /// Returns the number of sounds currently in the queue.
+    #[allow(clippy::len_without_is_empty)]
     #[inline]
     pub fn len(&self) -> usize {
         self.sink.len()
     }
+
+    /// Attempts to seek to a given position in the current source.
+    ///
+    /// This blocks between 0 and ~5 milliseconds.
+    ///
+    /// As long as the duration of the source is known seek is guaranteed to saturate
+    /// at the end of the source. For example given a source that reports a total duration
+    /// of 42 seconds calling `try_seek()` with 60 seconds as argument will seek to
+    /// 42 seconds.
+    ///
+    /// # Errors
+    /// This function will return [`SeekError::NotSupported`] if one of the underlying
+    /// sources does not support seeking.  
+    ///
+    /// It will return an error if an implementation ran
+    /// into one during the seek.  
+    ///
+    /// When seeking beyond the end of a source this
+    /// function might return an error if the duration of the source is not known.
+    pub fn try_seek(&self, pos: Duration) -> Result<(), SeekError> {
+        self.sink.try_seek(pos)
+    }
+
+    /// Returns the position of the sound that's being played.
+    ///
+    /// This takes into account any speedup or delay applied.
+    ///
+    /// Example: if you apply a speedup of *2* to an mp3 decoder source and
+    /// [`get_pos()`](Sink::get_pos) returns *5s* then the position in the mp3
+    /// recording is *10s* from its start.
+    #[inline]
+    pub fn get_pos(&self) -> Duration {
+        self.sink.get_pos()
+    }
 }
diff --git a/src/stream.rs b/src/stream.rs
index 3d1ae73..9437930 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -18,8 +18,8 @@ const HZ_44100: cpal::SampleRate = cpal::SampleRate(44_100);
 ///
 /// If this is dropped, playback will end, and the associated output stream will be disposed.
 pub struct OutputStream {
-    _stream: cpal::Stream,
     mixer: Arc<Mixer<f32>>,
+    _stream: cpal::Stream,
 }
 
 impl OutputStream {