diff -urN midi_prog-/Makefile midi_prog/Makefile
--- midi_prog-/Makefile	Wed Mar 25 01:00:03 2015
+++ midi_prog/Makefile	Thu Mar 26 00:00:00 2015
@@ -1,6 +1,6 @@
 CC = gcc
 LIB = -lm -lpthread -L../cui -lcui
-TARG = prog41
+TARG = prog42
 OBJS = main.o vcf.o ch.o delay.o stat.o note.o env.o tone.o filter.o lfo.o modu.o vco.o wave.o out.o rd.o util.o
 OBJS += cui_tone.o
 CFLAGS += -Wall -I..
diff -urN midi_prog-/ch.c midi_prog/ch.c
--- midi_prog-/ch.c	Fri Jan 24 00:00:00 2014
+++ midi_prog/ch.c	Thu Mar 26 00:00:00 2015
@@ -3,6 +3,38 @@
 struct ch_rec ch_inf[ MIDI_CH_N ];
 
 void
+ch_init(int ac, char **av)
+{
+	int i;
+	char *s, s_ch[8], buf[1024];
+	double v;
+
+	for(i=0; i<MIDI_CH_N; i++){
+		ch_inf[i].vol = 0;
+		ch_inf[i].pan = 1<<(14-1);
+		ch_inf[i].bend = 0;
+		ch_inf[i].rpn = 0;
+		ch_inf[i].bend_range = 2;
+		ch_inf[i].prog =-1;
+
+		ch_inf[i].adj_vol = 1.0;
+	}
+
+	if((s = opt_str("-vol", ac, av, NULL)) != NULL){
+		while(*s && sscanf(s, "%[^:]:%s", s_ch, buf) == 2){
+			v = strtod(buf, &s);
+			if(strcmp(s_ch, "all") == 0){
+				for(i=0; i<MIDI_CH_N; i++) ch_inf[i].adj_vol = v;
+			}else{
+				int ch = strtol(s_ch, NULL, 0);
+				if(0 <= ch && ch < MIDI_CH_N) ch_inf[ch].adj_vol = v;
+			}
+			if(*s == ',') s++;
+		}
+	}
+}
+
+void
 msb_set(int *vp, int v)
 {
 	*vp &= ~(127<<7);
diff -urN midi_prog-/ch.h midi_prog/ch.h
--- midi_prog-/ch.h	Fri Jan 24 00:00:00 2014
+++ midi_prog/ch.h	Thu Mar 26 00:00:00 2015
@@ -1,6 +1,8 @@
 #ifndef __CH_H__
 #define __CH_H__
 
+#include "util.h"
+
 #define MIDI_CH_N	16
 
 struct ch_rec{
@@ -10,10 +12,12 @@
 	int rpn;
 	int bend_range;
 	int prog;
+	double adj_vol;
 };
 
 extern struct ch_rec ch_inf[ MIDI_CH_N ];
 
+void ch_init(int ac, char **av);
 void msb_set(int *vp, int v);
 void lsb_set(int *vp, int v);
 
diff -urN midi_prog-/main.c midi_prog/main.c
--- midi_prog-/main.c	Wed Mar 25 00:00:02 2015
+++ midi_prog/main.c	Thu Mar 26 00:00:00 2015
@@ -80,14 +80,7 @@
 	out_init(&otr, ac, av);
 	note_buf_init();
 	stat_buf_init();
-	for(i=0; i<MIDI_CH_N; i++){
-		ch_inf[i].vol = 0;
-		ch_inf[i].pan = 1<<(14-1);
-		ch_inf[i].bend = 0;
-		ch_inf[i].rpn = 0;
-		ch_inf[i].bend_range = 2;
-		ch_inf[i].prog =-1;
-	}
+	ch_init(ac, av);
 
 	if(pthread_create(&pth, NULL, pth_func, av)) ERR("pthrad_create");
 
diff -urN midi_prog-/note.c midi_prog/note.c
--- midi_prog-/note.c	Sat Jan 25 00:00:00 2014
+++ midi_prog/note.c	Thu Mar 26 00:00:00 2015
@@ -85,7 +85,7 @@
 	}
 	v = sum_v;
 
-	v *= (nt->velo * (1.0 / 127)) * (ch_inf[nch].vol * (1.0 / ((1<<14)-1)));
+	v *= (nt->velo * (1.0 / 127)) * (ch_inf[nch].vol * (1.0 / ((1<<14)-1))) * ch_inf[nch].adj_vol;
 	if(ot->ch_num == 1){
 		*vl += v;
 	}else{