diff -urN midi_prog-/pitdet.c midi_prog/pitdet.c
--- midi_prog-/pitdet.c	Thu Aug 13 00:00:00 2015
+++ midi_prog/pitdet.c	Fri Aug 14 00:00:00 2015
@@ -32,27 +32,34 @@
 		pitch_init(&pd->arr[j], smp_freq, freq, wn, abuf_wsec);
 	}
 
-	pd->oldest_sec = -1;
-	pd->newest_sec = -1;
+	pd->oldest.sec = -1;
+	pd->oldest.update = 0;
+	pd->newest.sec = -1;
+	pd->newest.update = 0;
+
+	pd->max_v = -1;
 }
 
 void
 pitdet_add(struct pitdet *pd, double v)
 {
 	int j;
-	double sec;
+	double sec, osec = -1, nsec = -1;
 
-	pd->oldest_sec = -1;
-	pd->newest_sec = -1;
+	pd->max_v = -1;
 
 	for(j=0; j<pd->m; j++){
 		struct pitch *p = &pd->arr[j];
 		pitch_add(p, v);
 
 		sec = tbuf_oldest_sec(&p->ab.tb);
-		if(pd->oldest_sec < 0 || sec > pd->oldest_sec) pd->oldest_sec = sec;
+		if(osec < 0 || sec > osec) osec = sec;
 
 		sec = tbuf_newest_sec(&p->ab.tb);
-		if(pd->newest_sec < 0 || sec < pd->newest_sec) pd->newest_sec = sec;
+		if(nsec < 0 || sec < nsec) nsec = sec;
+
+		if(p->ab.max_v > pd->max_v) pd->max_v = p->ab.max_v;
 	}
+	if((pd->oldest.update = (pd->oldest.sec != osec)) != 0) pd->oldest.sec = osec;
+	if((pd->newest.update = (pd->newest.sec != nsec)) != 0) pd->newest.sec = nsec;
 }
diff -urN midi_prog-/pitdet.h midi_prog/pitdet.h
--- midi_prog-/pitdet.h	Thu Aug 13 00:00:00 2015
+++ midi_prog/pitdet.h	Fri Aug 14 00:00:00 2015
@@ -7,7 +7,13 @@
 	int div;
 	int m;
 	struct pitch *arr;
-	double oldest_sec, newest_sec;
+
+	struct{
+		double sec;
+		int update;
+	} oldest, newest;
+
+	double max_v;
 };
 
 double pitdet_note_to_freq(double note);
diff -urN midi_prog-/tool.c midi_prog/tool.c
--- midi_prog-/tool.c	Thu Aug 13 00:00:00 2015
+++ midi_prog/tool.c	Fri Aug 14 00:00:00 2015
@@ -2,6 +2,79 @@
 #include "in.h"
 #include "pitdet.h"
 
+static void
+show_spectre_modify_area(struct pitdet *pd, int ac, char **av, char *s, int *ret_js, int *ret_je)
+{
+	int show_w = opt_int("-show_w", ac, av, -1);
+	int cen, div, j, js, je;
+
+	*ret_js = js = 0;
+	*ret_je = je = pd->m;
+	if(show_w < 0) return;
+
+	div = pd->div;
+	cen = opt_int("-show_cen_note", ac, av, 64) * div;
+
+	for(;;){
+		int over, a, b;
+		int w = strlen(s) + je - js;
+		for(j=js; j<je; j++)
+			if(div > 1 && j % div == div-1 && j != je-1)
+				w++;
+		if(w <= show_w) break;
+
+		over = w - show_w;
+		/*
+			next_js = js + a
+			next_je = je - b
+
+			(a + b)(1 + 1 / div) = over
+			a + b = over / (1 + 1 / div) = over * div / (div + 1)
+			b = over * div / (div + 1) - a
+
+			(next_js + next_je) / 2 = cen
+			js + je + a - b - over = 2 cen
+			js + je + a - (over * div / (div + 1) - a) - over = 2 cen
+			js + je + 2a = 2 cen + over * (1 + div / (div + 1))
+			2a = 2cen + over * (1 + div / (div + 1)) - (js + je)
+			a = cen + ( over * (1 + div / (div + 1)) - (js + je) ) / 2
+
+		 */
+		a = cen + ( over * (1 + div / (div + 1)) - (js + je) ) / 2;
+		b = a > 0 ? over * div / (div + 1) - a : over;
+		js += a;
+		je -= b;
+	}
+	*ret_js = js;
+	*ret_je = je;
+}
+
+static void
+show_spectre(struct pitdet *pd, int ac, char **av)
+{
+	int j, js, je;
+	char s[32];
+	double sec = pd->oldest.sec;
+
+	sprintf(s, "sec=%f ", sec);
+	printf("%s", s);
+
+	show_spectre_modify_area(pd, ac, av, s, &js, &je);
+
+	for(j=js; j<je; j++){
+		struct pitch *p = &pd->arr[j];
+		double v = tbuf_get_dbl(&p->ab.tb, sec);
+		int iv = (int)(10 * v / pd->max_v);
+
+		if(iv < 0) iv = -1;
+		if(iv > 9) iv = 10;
+		putchar("-0123456789+"[ iv + 1]);
+
+		if(pd->div > 1 && j % pd->div == pd->div-1 && j != je-1) putchar(' ');
+	}
+	putchar('\n');
+}
+
 int
 main(int ac, char **av)
 {
@@ -10,20 +83,16 @@
 
 	struct pitdet pd;
 	int div = opt_int("-div", ac, av, 1);
-	double abuf_wsec = opt_double("-abuf_wsec", ac, av, 0.5);
-	double old_bak = 0, new_bak = 0;
+	double abuf_wsec = opt_double("-abuf_wsec", ac, av, 2.5);
 
 	in_init(&in, ac, av);
 	pitdet_init(&pd, in.smp_freq, div, abuf_wsec);
 
 	while(in_do_mono(&in, &v) != EOF){
 		pitdet_add(&pd, v);
-		if( pd.oldest_sec > 0 && pd.newest_sec > 0 &&
-		    (pd.oldest_sec > old_bak || pd.newest_sec > new_bak) ){
-			printf("%f %f\n", pd.oldest_sec, pd.newest_sec);
-			old_bak = pd.oldest_sec;
-			new_bak = pd.newest_sec;
-		}
+		if(!pd.oldest.update) continue;
+		if(pd.oldest.sec < 0) continue;
+		show_spectre(&pd, ac, av);
 	}
 	return 0;
 }