diff --git a/Makefile b/Makefile
index c31ebb5..bb87775 100644
--- a/Makefile
+++ b/Makefile
@@ -22,5 +22,5 @@ clean:
 
 encode: encode.o mmap_file.o
 
-decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o ddc.o
+decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o ddc.o delay.o
 
diff --git a/decode.c b/decode.c
index a557a2f..e9f8795 100644
--- a/decode.c
+++ b/decode.c
@@ -9,6 +9,7 @@
 #include "mmap_file.h"
 #include "pcm.h"
 #include "ddc.h"
+#include "delay.h"
 
 float lerp(float a, float b, float x)
 {
@@ -31,36 +32,6 @@ float limit(float min, float max, float x)
 	return tmp > max ? max : tmp;
 }
 
-typedef struct {
-	float *s;
-	int last;
-	int len;
-} delay_t;
-
-float do_delay(delay_t *d, float input)
-{
-	d->s[d->last] = input;
-	d->last = (d->last + 1) < d->len ? d->last + 1 : 0;
-	return d->s[d->last];
-}
-
-delay_t *alloc_delay(int samples)
-{
-	int len = samples + 1;
-	delay_t *d = malloc(sizeof(delay_t));
-	d->s = malloc(sizeof(float) * len);
-	d->last = 0;
-	d->len = len;
-	for (int i = 0; i < len; i++)
-		d->s[i] = 0.0;
-	return d;
-}
-void free_delay(delay_t *delay)
-{
-	free(delay->s);
-	free(delay);
-}
-
 typedef struct {
 	uint32_t ChunkID;
 	uint32_t ChunkSize;
diff --git a/delay.c b/delay.c
new file mode 100644
index 0000000..6d52406
--- /dev/null
+++ b/delay.c
@@ -0,0 +1,28 @@
+
+#include "delay.h"
+#include <stdlib.h>
+
+float do_delay(delay_t *d, float input)
+{
+	d->s[d->last] = input;
+	d->last = (d->last + 1) < d->len ? d->last + 1 : 0;
+	return d->s[d->last];
+}
+
+delay_t *alloc_delay(int samples)
+{
+	int len = samples + 1;
+	delay_t *d = malloc(sizeof(delay_t));
+	d->s = malloc(sizeof(float) * len);
+	d->last = 0;
+	d->len = len;
+	for (int i = 0; i < len; i++)
+		d->s[i] = 0.0;
+	return d;
+}
+void free_delay(delay_t *delay)
+{
+	free(delay->s);
+	free(delay);
+}
+
diff --git a/delay.h b/delay.h
new file mode 100644
index 0000000..4e7979d
--- /dev/null
+++ b/delay.h
@@ -0,0 +1,14 @@
+
+#ifndef DELAY_H
+#define DELAY_H
+typedef struct {
+	float *s;
+	int last;
+	int len;
+} delay_t;
+
+float do_delay(delay_t *, float);
+delay_t *alloc_delay(int);
+void free_delay(delay_t *);
+#endif
+