diff -urN midi_prog-/in.c midi_prog/in.c
--- midi_prog-/in.c	Fri Aug 28 00:00:00 2015
+++ midi_prog/in.c	Sat Aug 29 00:00:00 2015
@@ -7,7 +7,7 @@
 	out_init(&otr, ac, av);
 	*inp = otr;
 	if(ifn == NULL) ifn = "-i";
-	inp->fp = fp_get(ifn, ac, av, "-", "r");
+	inp->fp = fp_get(ifn, ac, av, "-", "r", &inp->fn);
 }
 
 int
diff -urN midi_prog-/out.c midi_prog/out.c
--- midi_prog-/out.c	Fri Aug 28 00:00:00 2015
+++ midi_prog/out.c	Sat Aug 29 00:00:00 2015
@@ -32,7 +32,7 @@
 	ot->sign = (opt_idx("-u", ac, av) < 0);
 	ot->ch_num = opt_int("-c", ac, av, 2);
 
-	ot->fp = fp_get("-o", ac, av, "-", "w");
+	ot->fp = fp_get("-o", ac, av, "-", "w", &ot->fn);
 	cmd[0] = '\0';
 	fn = "";
 	if(opt_idx("-play", ac, av) >= 0){
diff -urN midi_prog-/out.h midi_prog/out.h
--- midi_prog-/out.h	Fri Aug 28 00:00:00 2015
+++ midi_prog/out.h	Sat Aug 29 00:00:00 2015
@@ -8,6 +8,7 @@
 	int bit_len;
 	int sign;
 	int ch_num;
+	char *fn;
 	FILE *fp;
 
 	int base;
diff -urN midi_prog-/rawmix2.c midi_prog/rawmix2.c
--- midi_prog-/rawmix2.c	Fri Aug 28 00:00:00 2015
+++ midi_prog/rawmix2.c	Sat Aug 29 00:00:00 2015
@@ -2,35 +2,82 @@
 #include "in.h"
 #include "out.h"
 
-int
-main(int ac, char **av)
+struct mix{
+	int ch, en;
+	in_rec_t in;
+	double vol, pan;
+};
+
+void
+mix_init(struct mix *m, int ch, int ac, char **av)
 {
-	struct out_rec otr;
-	in_rec_t in_l, in_r;
+	char key[16], *opt, *a_av[ AVSZ ];
+	int a_ac = AVSZ;
 
-	char *l_opt = opt_str("-L", ac, av, NULL);
-	char *r_opt = opt_str("-R", ac, av, NULL);
-	char *l_av[ AVSZ ], *r_av[ AVSZ ];
-	int l_ac = AVSZ, r_ac = AVSZ;
+	m->ch = ch;
+	sprintf(key, "-CH%d", ch);
+	opt = opt_str(key, ac, av, NULL);
+	m->en = (opt != NULL);
+	if(!m->en) return;
+
+	line_to_ac_av(opt, &a_ac, a_av);
+	in_init(&m->in, a_ac, a_av, NULL);
+	m->vol = opt_double("-vol", a_ac, a_av, 1);
+	m->pan = opt_double("-pan", a_ac, a_av, 0.5);
+}
 
-	opt_show(ac, av);
+int
+mix_get(struct mix *m, double *vs)
+{
+	int ret;
+	double v = 0;
 
-	line_to_ac_av(l_opt, &l_ac, l_av);
-	line_to_ac_av(r_opt, &r_ac, r_av);
+	if(!m->en) return EOF;
+	if((ret = in_do_mono(&m->in, &v)) == EOF){
+		m->en = 0;
+		return EOF;
+	}
+	v *= m->vol;
+	vs[0] = (1 - m->pan) * v;
+	vs[1] = m->pan * v;
+	return ret;
+}
 
-	in_init(&in_l, l_ac, l_av, NULL);
-	in_init(&in_r, r_ac, r_av, NULL);
-	out_init(&otr, ac, av);
+#define MIX_N	16
 
-	out_show_info(&otr);
+int
+main(int ac, char **av)
+{
+	struct mix mx[ MIX_N ];
+	struct out_rec otr;
+	int i;
+
+	for(i=0; i<MIX_N; i++){
+		struct mix *m = &mx[i];
+		mix_init(m, i, ac, av);
+		if(m->in.fp == NULL){
+			fprintf(stderr, "i=%d fn=%s\n", i, m->in.fn);
+			ERR("Can't open");
+		}
+	}
 
-	if(in_l.fp == NULL || in_r.fp == NULL || otr.fp == NULL) ERR("Can't open");
+	out_init(&otr, ac, av);
+	if(otr.fp == NULL) ERR("Can't open");
 
 	while(1){
-		double v[2];
-		if(in_do_mono(&in_l, &v[0]) == EOF) break;
-		if(in_do_mono(&in_r, &v[1]) == EOF) break;
-		out_do2(&otr, v);
+		double vsum[2] = { 0, 0 };
+		int cnt = 0;
+		for(i=0; i<MIX_N; i++){
+			struct mix *m = &mx[i];
+			double vs[2] = { 0, 0 };
+			if(!m->en) continue;
+			cnt++;
+			mix_get(m, vs);
+			vsum[0] += vs[0];
+			vsum[1] += vs[1];
+		}
+		if(cnt == 0) break;
+		out_do2(&otr, vsum);
 	}
 	fclose(otr.fp);
 	return 0;
diff -urN midi_prog-/util.c midi_prog/util.c
--- midi_prog-/util.c	Fri Aug 28 00:00:00 2015
+++ midi_prog/util.c	Sat Aug 29 00:00:00 2015
@@ -154,9 +154,10 @@
 }
 
 FILE *
-fp_get(char *key, int ac, char **av, char *def_fn, char *mode)
+fp_get(char *key, int ac, char **av, char *def_fn, char *mode, char **ret_fn)
 {
 	char *fn = opt_str(key, ac, av, def_fn);
+	if(ret_fn) *ret_fn = fn;
 	if(fn == NULL) return NULL;
 	if(strcmp(fn, "-") == 0) return strcmp(mode, "r") == 0 ? stdin : stdout;
 	return fopen(fn, mode);
diff -urN midi_prog-/util.h midi_prog/util.h
--- midi_prog-/util.h	Fri Aug 28 00:00:00 2015
+++ midi_prog/util.h	Sat Aug 29 00:00:00 2015
@@ -46,7 +46,7 @@
 
 int dbl_max_idx(double *p, int next_bytes, int n, double *ret_v);
 
-FILE *fp_get(char *key, int ac, char **av, char *def_fn, char *mode);
+FILE *fp_get(char *key, int ac, char **av, char *def_fn, char *mode, char **ret_fn);
 
 
 struct chatt{
diff -urN midi_prog-/voco.c midi_prog/voco.c
--- midi_prog-/voco.c	Fri Aug 28 00:00:00 2015
+++ midi_prog/voco.c	Sat Aug 29 00:00:00 2015
@@ -97,9 +97,10 @@
 	sscanf(opt_str("-band", ac, av, "500,3000/16"), "%d,%d/%d", &band.fl, &band.fh, &band.n);
 
 	out_init(&otr, ac, av);
-	otr.fp = fp_get("-o", ac, av, "-", "w");
+	otr.fp = fp_get("-o", ac, av, "-", "w", NULL);
 	in_init(&in_carrier, ac, av, "-carrier");
-	if(in_carrier.fp == NULL){
+	if(opt_idx("-carrier", ac, av) < 0){
+		in_carrier.fp = NULL;
 		vco_init(&vco, ac, av);
 	}
 	in_init(&in_voice, ac, av, "-voice");