diff --git a/gst/monoscope/convolve.c b/gst/monoscope/convolve.c
index 913773431e..35f18ece50 100644
--- a/gst/monoscope/convolve.c
+++ b/gst/monoscope/convolve.c
@@ -83,14 +83,13 @@ typedef union stack_entry_s
 }
 stack_entry;
 
-#define STACK_SIZE (CONVOLVE_DEPTH * 3)
-
 struct _struct_convolve_state
 {
-  double left[CONVOLVE_BIG];
-  double right[CONVOLVE_SMALL * 3];
-  double scratch[CONVOLVE_SMALL * 3];
-  stack_entry stack[STACK_SIZE + 1];
+  int depth, small, big, stack_size;
+  double *left;
+  double *right;
+  double *scratch;
+  stack_entry *stack;
 };
 
 /*
@@ -100,9 +99,20 @@ struct _struct_convolve_state
  * The pointer should be freed when it is finished with, by convolve_close().
  */
 convolve_state *
-convolve_init (void)
+convolve_init (int depth)
 {
-  return (convolve_state *) calloc (1, sizeof (convolve_state));
+  convolve_state *state;
+
+  state = malloc (sizeof (convolve_state));
+  state->depth = depth;
+  state->small = (1 << depth);
+  state->big = (2 << depth);
+  state->stack_size = depth * 3;
+  state->left = calloc (state->big, sizeof (double));
+  state->right = calloc (state->small * 3, sizeof (double));
+  state->scratch = calloc (state->small * 3, sizeof (double));
+  state->stack = calloc (state->stack_size + 1, sizeof (stack_entry));
+  return state;
 }
 
 /*
@@ -111,6 +121,10 @@ convolve_init (void)
 void
 convolve_close (convolve_state * state)
 {
+  free (state->left);
+  free (state->right);
+  free (state->scratch);
+  free (state->stack);
   free (state);
 }
 
@@ -273,13 +287,13 @@ convolve_match (const int *lastchoice, const short *input,
   double *left = state->left;
   double *right = state->right;
   double *scratch = state->scratch;
-  stack_entry *top = state->stack + (STACK_SIZE - 1);
+  stack_entry *top = state->stack + (state->stack_size - 1);
 
-  for (i = 0; i < CONVOLVE_BIG; i++)
+  for (i = 0; i < state->big; i++)
     left[i] = input[i];
 
-  for (i = 0; i < CONVOLVE_SMALL; i++) {
-    double a = lastchoice[(CONVOLVE_SMALL - 1) - i];
+  for (i = 0; i < state->small; i++) {
+    double a = lastchoice[(state->small - 1) - i];
 
     right[i] = a;
     avg += a;
@@ -288,32 +302,32 @@ convolve_match (const int *lastchoice, const short *input,
   /* We adjust the smaller of the two input arrays to have average
    * value 0.  This makes the eventual result insensitive to both
    * constant offsets and positive multipliers of the inputs. */
-  avg /= CONVOLVE_SMALL;
-  for (i = 0; i < CONVOLVE_SMALL; i++)
+  avg /= state->small;
+  for (i = 0; i < state->small; i++)
     right[i] -= avg;
   /* End-of-stack marker. */
   top[1].b.null = scratch;
   top[1].b.main = NULL;
-  /* The low SMALLxSMALL, of which we want the high outputs. */
+  /* The low (small x small) part, of which we want the high outputs. */
   top->v.left = left;
   top->v.right = right;
-  top->v.out = right + CONVOLVE_SMALL;
-  convolve_run (top, CONVOLVE_SMALL, scratch);
+  top->v.out = right + state->small;
+  convolve_run (top, state->small, scratch);
 
-  /* The high SMALLxSMALL, of which we want the low outputs. */
-  top->v.left = left + CONVOLVE_SMALL;
+  /* The high (small x small) part, of which we want the low outputs. */
+  top->v.left = left + state->small;
   top->v.right = right;
   top->v.out = right;
-  convolve_run (top, CONVOLVE_SMALL, scratch);
+  convolve_run (top, state->small, scratch);
 
   /* Now find the best position amoungs this.  Apart from the first
    * and last, the required convolution outputs are formed by adding
    * outputs from the two convolutions above. */
-  best = right[CONVOLVE_BIG - 1];
-  right[CONVOLVE_BIG + CONVOLVE_SMALL + 1] = 0;
+  best = right[state->big - 1];
+  right[state->big + state->small - 1] = 0;
   p = -1;
-  for (i = 0; i < CONVOLVE_SMALL; i++) {
-    double a = right[i] + right[i + CONVOLVE_BIG];
+  for (i = 0; i < state->small; i++) {
+    double a = right[i] + right[i + state->big];
 
     if (a > best) {
       best = a;
@@ -326,18 +340,18 @@ convolve_match (const int *lastchoice, const short *input,
   {
     /* This is some debugging code... */
     best = 0;
-    for (i = 0; i < CONVOLVE_SMALL; i++)
+    for (i = 0; i < state->small; i++)
       best += ((double) input[i + p]) * ((double) lastchoice[i] - avg);
 
-    for (i = 0; i <= CONVOLVE_SMALL; i++) {
+    for (i = 0; i <= state->small; i++) {
       double tot = 0;
       unsigned int j;
 
-      for (j = 0; j < CONVOLVE_SMALL; j++)
+      for (j = 0; j < state->small; j++)
         tot += ((double) input[i + j]) * ((double) lastchoice[j] - avg);
       if (tot > best)
         printf ("(%i)", i);
-      if (tot != left[i + (CONVOLVE_SMALL - 1)])
+      if (tot != left[i + (state->small - 1)])
         printf ("!");
     }
 
diff --git a/gst/monoscope/convolve.h b/gst/monoscope/convolve.h
index 64da744452..d6a7f05cca 100644
--- a/gst/monoscope/convolve.h
+++ b/gst/monoscope/convolve.h
@@ -31,16 +31,10 @@
 extern "C" {
 #endif
 
-/* convolve_match takes two blocks, one twice the size of the other.  The
- * sizes of these are CONVOLVE_BIG and CONVOLVE_SMALL respectively. */
-#define CONVOLVE_DEPTH 8
-#define CONVOLVE_SMALL (1 << CONVOLVE_DEPTH)
-#define CONVOLVE_BIG (CONVOLVE_SMALL * 2)
-
-/* Convolution stuff */
+/* Convolution state */
 typedef struct _struct_convolve_state convolve_state;
 
-convolve_state *convolve_init (void);
+convolve_state *convolve_init (int depth);
 void convolve_close (convolve_state * state);
 
 int convolve_match (const int * lastchoice,
diff --git a/gst/monoscope/monoscope.c b/gst/monoscope/monoscope.c
index e0c7651657..9606a34b06 100644
--- a/gst/monoscope/monoscope.c
+++ b/gst/monoscope/monoscope.c
@@ -63,12 +63,12 @@ monoscope_init (guint32 resx, guint32 resy)
   struct monoscope_state *stateptr;
 
   /* I didn't program monoscope to only do 256*128, but it works that way */
-  g_return_val_if_fail (resx == 256, 0);
-  g_return_val_if_fail (resy == 128, 0);
+  g_return_val_if_fail (resx == scope_width, 0);
+  g_return_val_if_fail (resy == scope_height, 0);
   stateptr = calloc (1, sizeof (struct monoscope_state));
   if (stateptr == 0)
     return 0;
-  stateptr->cstate = convolve_init ();
+  stateptr->cstate = convolve_init (convolver_depth);
   colors_init (stateptr->colors);
   return stateptr;
 }
@@ -81,9 +81,8 @@ monoscope_close (struct monoscope_state *stateptr)
 }
 
 guint32 *
-monoscope_update (struct monoscope_state *stateptr, gint16 data[512])
+monoscope_update (struct monoscope_state *stateptr, gint16 data[convolver_big])
 {
-  /* Note that CONVOLVE_BIG must == data size here, ie 512. */
   /* Really, we want samples evenly spread over the available data.
    * Just taking a continuous chunk will do for now, though. */
   int i;
@@ -95,14 +94,14 @@ monoscope_update (struct monoscope_state *stateptr, gint16 data[512])
   int factor;
   int val;
   int max = 1;
-  short *thisEq = stateptr->copyEq;
+  gint16 *thisEq = stateptr->copyEq;
 
-  memcpy (thisEq, data, sizeof (short) * CONVOLVE_BIG);
-  val = convolve_match (stateptr->avgEq, stateptr->copyEq, stateptr->cstate);
+  memcpy (thisEq, data, sizeof (short) * convolver_big);
+  val = convolve_match (stateptr->avgEq, thisEq, stateptr->cstate);
   thisEq += val;
 
-  memset (stateptr->display, 0, 256 * 128 * sizeof (guint32));
-  for (i = 0; i < 256; i++) {
+  memset (stateptr->display, 0, scope_width * scope_height * sizeof (guint32));
+  for (i = 0; i < convolver_small; i++) {
     foo = thisEq[i] + (stateptr->avgEq[i] >> 1);
     stateptr->avgEq[i] = foo;
     if (foo < 0)
diff --git a/gst/monoscope/monoscope.h b/gst/monoscope/monoscope.h
index 8e7d759137..3e79fe49de 100644
--- a/gst/monoscope/monoscope.h
+++ b/gst/monoscope/monoscope.h
@@ -4,21 +4,24 @@
 #include <glib.h>
 #include "convolve.h"
 
+#define convolver_depth 8
+#define convolver_small (1 << convolver_depth)
+#define convolver_big (2 << convolver_depth)
 #define scope_width 256
 #define scope_height 128
 
 struct monoscope_state {
-    gint16 copyEq[CONVOLVE_BIG];
-    int avgEq[CONVOLVE_SMALL];      /* a running average of the last few. */
-    int avgMax;                     /* running average of max sample. */
-    guint32 display[(scope_width + 1) * (scope_height + 1)];
+  short copyEq[convolver_big];
+  int avgEq[convolver_small];      /* a running average of the last few. */
+  int avgMax;                     /* running average of max sample. */
+  guint32 display[scope_width * scope_height];
 
-    convolve_state *cstate;
-    guint32 colors[64];
+  convolve_state *cstate;
+  guint32 colors[64];
 };
 
 struct monoscope_state * monoscope_init (guint32 resx, guint32 resy);
-guint32 * monoscope_update (struct monoscope_state * stateptr, gint16 data [512]);
+guint32 * monoscope_update (struct monoscope_state * stateptr, gint16 data [convolver_big]);
 void monoscope_close (struct monoscope_state * stateptr);
 
 #endif