diff --git a/audio.go b/audio.go
index e3929e9..54ec70f 100644
--- a/audio.go
+++ b/audio.go
@@ -30,8 +30,105 @@ type (
 		Output() AudioOutput
 		Close() error
 	}
+
+	// Synth represents a state of a synthesizer, compiled from a Patch.
+	Synth interface {
+		// Render tries to fill a stereo signal buffer with sound from the
+		// synthesizer, until either the buffer is full or a given number of
+		// timesteps is advanced. Normally, 1 sample = 1 unit of time, but speed
+		// modulations may change this. It returns the number of samples filled (in
+		// stereo samples i.e. number of elements of AudioBuffer filled), the
+		// number of sync outputs written, the number of time steps time advanced,
+		// and a possible error.
+		Render(buffer AudioBuffer, maxtime int) (sample int, time int, err error)
+
+		// Update recompiles a patch, but should maintain as much as possible of its
+		// state as reasonable. For example, filters should keep their state and
+		// delaylines should keep their content. Every change in the Patch triggers
+		// an Update and if the Patch would be started fresh every time, it would
+		// lead to very choppy audio.
+		Update(patch Patch, bpm int) error
+
+		// Trigger triggers a note for a given voice. Called between synth.Renders.
+		Trigger(voice int, note byte)
+
+		// Release releases the currently playing note for a given voice. Called
+		// between synth.Renders.
+		Release(voice int)
+	}
+
+	// Synther compiles a given Patch into a Synth, throwing errors if the
+	// Patch is malformed.
+	Synther interface {
+		Synth(patch Patch, bpm int) (Synth, error)
+	}
 )
 
+// Play plays the Song by first compiling the patch with the given Synther,
+// returning the stereo audio buffer as a result (and possible errors).
+func Play(synther Synther, song Song) (AudioBuffer, error) {
+	err := song.Validate()
+	if err != nil {
+		return nil, err
+	}
+	synth, err := synther.Synth(song.Patch, song.BPM)
+	if err != nil {
+		return nil, fmt.Errorf("sointu.Play failed: %v", err)
+	}
+	curVoices := make([]int, len(song.Score.Tracks))
+	for i := range curVoices {
+		curVoices[i] = song.Score.FirstVoiceForTrack(i)
+	}
+	initialCapacity := song.Score.LengthInRows() * song.SamplesPerRow()
+	buffer := make(AudioBuffer, 0, initialCapacity)
+	rowbuffer := make(AudioBuffer, song.SamplesPerRow())
+	for row := 0; row < song.Score.LengthInRows(); row++ {
+		patternRow := row % song.Score.RowsPerPattern
+		pattern := row / song.Score.RowsPerPattern
+		for t := range song.Score.Tracks {
+			order := song.Score.Tracks[t].Order
+			if pattern < 0 || pattern >= len(order) {
+				continue
+			}
+			patternIndex := song.Score.Tracks[t].Order[pattern]
+			patterns := song.Score.Tracks[t].Patterns
+			if patternIndex < 0 || int(patternIndex) >= len(patterns) {
+				continue
+			}
+			pattern := patterns[patternIndex]
+			if patternRow < 0 || patternRow >= len(pattern) {
+				continue
+			}
+			note := pattern[patternRow]
+			if note > 0 && note <= 1 { // anything but hold causes an action.
+				continue
+			}
+			synth.Release(curVoices[t])
+			if note > 1 {
+				curVoices[t]++
+				first := song.Score.FirstVoiceForTrack(t)
+				if curVoices[t] >= first+song.Score.Tracks[t].NumVoices {
+					curVoices[t] = first
+				}
+				synth.Trigger(curVoices[t], note)
+			}
+		}
+		tries := 0
+		for rowtime := 0; rowtime < song.SamplesPerRow(); {
+			samples, time, err := synth.Render(rowbuffer, song.SamplesPerRow()-rowtime)
+			if err != nil {
+				return buffer, fmt.Errorf("render failed: %v", err)
+			}
+			rowtime += time
+			buffer = append(buffer, rowbuffer[:samples]...)
+			if tries > 100 {
+				return nil, fmt.Errorf("Song speed modulation likely so slow that row never advances; error at pattern %v, row %v", pattern, patternRow)
+			}
+		}
+	}
+	return buffer, nil
+}
+
 // Fill fills the AudioBuffer using a Synth, disregarding all syncs and time
 // limits. Note that this will change the state of the Synth.
 func (buffer AudioBuffer) Fill(synth Synth) error {
diff --git a/synth.go b/synth.go
deleted file mode 100644
index 20fc382..0000000
--- a/synth.go
+++ /dev/null
@@ -1,104 +0,0 @@
-package sointu
-
-import (
-	"fmt"
-)
-
-type (
-	// Synth represents a state of a synthesizer, compiled from a Patch.
-	Synth interface {
-		// Render tries to fill a stereo signal buffer with sound from the
-		// synthesizer, until either the buffer is full or a given number of
-		// timesteps is advanced. Normally, 1 sample = 1 unit of time, but speed
-		// modulations may change this. It returns the number of samples filled (in
-		// stereo samples i.e. number of elements of AudioBuffer filled), the
-		// number of sync outputs written, the number of time steps time advanced,
-		// and a possible error.
-		Render(buffer AudioBuffer, maxtime int) (sample int, time int, err error)
-
-		// Update recompiles a patch, but should maintain as much as possible of its
-		// state as reasonable. For example, filters should keep their state and
-		// delaylines should keep their content. Every change in the Patch triggers
-		// an Update and if the Patch would be started fresh every time, it would
-		// lead to very choppy audio.
-		Update(patch Patch, bpm int) error
-
-		// Trigger triggers a note for a given voice. Called between synth.Renders.
-		Trigger(voice int, note byte)
-
-		// Release releases the currently playing note for a given voice. Called
-		// between synth.Renders.
-		Release(voice int)
-	}
-
-	// Synther compiles a given Patch into a Synth, throwing errors if the
-	// Patch is malformed.
-	Synther interface {
-		Synth(patch Patch, bpm int) (Synth, error)
-	}
-)
-
-// Play plays the Song by first compiling the patch with the given Synther,
-// returning the stereo audio buffer as a result (and possible errors).
-func Play(synther Synther, song Song) (AudioBuffer, error) {
-	err := song.Validate()
-	if err != nil {
-		return nil, err
-	}
-	synth, err := synther.Synth(song.Patch, song.BPM)
-	if err != nil {
-		return nil, fmt.Errorf("sointu.Play failed: %v", err)
-	}
-	curVoices := make([]int, len(song.Score.Tracks))
-	for i := range curVoices {
-		curVoices[i] = song.Score.FirstVoiceForTrack(i)
-	}
-	initialCapacity := song.Score.LengthInRows() * song.SamplesPerRow()
-	buffer := make(AudioBuffer, 0, initialCapacity)
-	rowbuffer := make(AudioBuffer, song.SamplesPerRow())
-	for row := 0; row < song.Score.LengthInRows(); row++ {
-		patternRow := row % song.Score.RowsPerPattern
-		pattern := row / song.Score.RowsPerPattern
-		for t := range song.Score.Tracks {
-			order := song.Score.Tracks[t].Order
-			if pattern < 0 || pattern >= len(order) {
-				continue
-			}
-			patternIndex := song.Score.Tracks[t].Order[pattern]
-			patterns := song.Score.Tracks[t].Patterns
-			if patternIndex < 0 || int(patternIndex) >= len(patterns) {
-				continue
-			}
-			pattern := patterns[patternIndex]
-			if patternRow < 0 || patternRow >= len(pattern) {
-				continue
-			}
-			note := pattern[patternRow]
-			if note > 0 && note <= 1 { // anything but hold causes an action.
-				continue
-			}
-			synth.Release(curVoices[t])
-			if note > 1 {
-				curVoices[t]++
-				first := song.Score.FirstVoiceForTrack(t)
-				if curVoices[t] >= first+song.Score.Tracks[t].NumVoices {
-					curVoices[t] = first
-				}
-				synth.Trigger(curVoices[t], note)
-			}
-		}
-		tries := 0
-		for rowtime := 0; rowtime < song.SamplesPerRow(); {
-			samples, time, err := synth.Render(rowbuffer, song.SamplesPerRow()-rowtime)
-			if err != nil {
-				return buffer, fmt.Errorf("render failed: %v", err)
-			}
-			rowtime += time
-			buffer = append(buffer, rowbuffer[:samples]...)
-			if tries > 100 {
-				return nil, fmt.Errorf("Song speed modulation likely so slow that row never advances; error at pattern %v, row %v", pattern, patternRow)
-			}
-		}
-	}
-	return buffer, nil
-}