diff --git a/aucat/aproc.c b/aucat/aproc.c
index 00db513..de82a4f 100644
--- a/aucat/aproc.c
+++ b/aucat/aproc.c
@@ -1016,7 +1016,7 @@ struct aproc_ops mix_ops = {
 };
 
 struct aproc *
-mix_new(char *name, int maxlat, unsigned round)
+mix_new(char *name, int maxlat, unsigned round, unsigned autovol)
 {
 	struct aproc *p;
 
@@ -1027,6 +1027,7 @@ mix_new(char *name, int maxlat, unsigned round)
 	p->u.mix.maxlat = maxlat;
 	p->u.mix.ctl = NULL;
 	p->u.mix.mon = NULL;
+	p->u.mix.autovol = autovol;
 	return p;
 }
 
@@ -1040,6 +1041,9 @@ mix_setmaster(struct aproc *p)
 	struct abuf *i, *j;
 	int weight;
 
+	if (!p->u.mix.autovol)
+		return;
+
 	/*
 	 * count the number of inputs. If a set of inputs
 	 * uses channels that have no intersection, they are 
diff --git a/aucat/aproc.h b/aucat/aproc.h
index 86c707a..a85a7d2 100644
--- a/aucat/aproc.h
+++ b/aucat/aproc.h
@@ -140,6 +140,7 @@ struct aproc {
 			unsigned abspos;	/* frames produced */
 			struct aproc *ctl;	/* MIDI control/sync */
 			struct aproc *mon;	/* snoop output */
+			unsigned autovol;	/* adjust volume dynamically */
 		} mix;
 		struct {
 			unsigned idle;		/* frames since idleing */
@@ -239,7 +240,7 @@ void aproc_opos(struct aproc *, struct abuf *, int);
 
 struct aproc *rfile_new(struct file *);
 struct aproc *wfile_new(struct file *);
-struct aproc *mix_new(char *, int, unsigned);
+struct aproc *mix_new(char *, int, unsigned, unsigned);
 struct aproc *sub_new(char *, int, unsigned);
 struct aproc *resamp_new(char *, unsigned, unsigned);
 struct aproc *enc_new(char *, struct aparams *);
diff --git a/aucat/aucat.1 b/aucat/aucat.1
index c45b3d2..7f7faa3 100644
--- a/aucat/aucat.1
+++ b/aucat/aucat.1
@@ -42,6 +42,7 @@
 .Op Fl t Ar mode
 .Op Fl U Ar unit
 .Op Fl v Ar volume
+.Op Fl w Ar flag
 .Op Fl x Ar policy
 .Op Fl z Ar nframes
 .Ek
@@ -114,7 +115,7 @@ Preceding streams
 control MIDI ports
 .Pq Fl q ,
 and per-device options
-.Pq Fl abz
+.Pq Fl abwz
 apply to this device.
 Device mode and parameters are determined from streams
 attached to it.
@@ -255,6 +256,22 @@ of clients as long as their number is small enough.
 A good compromise is to use \-4dB attenuation (12 volume units)
 for each additional client expected
 (115 if 2 clients are expected, 103 for 3 clients, and so on).
+.It Fl w Ar flag
+Control whether the master volume resulting of all playback
+streams of the device is automatically adjusted.
+If the flag is
+.Va on ,
+then the master volume is lowered when necessary to ensure
+clipping never occurs.
+It should be set to
+.Va off
+to avoid lowering the volume twice if streams are already pre-scaled.
+Note that stream volumes can be manually set
+.Pq Fl v
+and if they are set correctly, the master volume doesn't need
+to be adjusted to avoid clipping.
+The default is
+.Va on .
 .It Fl x Ar policy
 Action when the output stream cannot accept
 recorded data fast enough or the input stream
@@ -298,7 +315,7 @@ to a 400 frame block size.
 .Pp
 On the command line,
 per-device parameters
-.Pq Fl abz
+.Pq Fl abwz
 must precede the device definition
 .Pq Fl f ,
 and per-stream parameters
diff --git a/aucat/aucat.c b/aucat/aucat.c
index 1f52819..eef8290 100644
--- a/aucat/aucat.c
+++ b/aucat/aucat.c
@@ -251,6 +251,7 @@ struct cfdev {
 	struct aparams ipar;		/* input (read) parameters */
 	struct aparams opar;		/* output (write) parameters */
 	unsigned hold;			/* open immediately */
+	unsigned autovol;		/* adjust volumes */
 	unsigned bufsz;			/* par.bufsz for sio device */
 	unsigned round;			/* par.round for sio device */
 	unsigned mode;			/* bitmap of MODE_XXX */
@@ -443,7 +444,7 @@ aucat_usage(void)
 	    "[-o file]\n\t"
 	    "[-q device] [-r rate] [-s name] [-t mode] [-U unit] "
 	    "[-v volume]\n\t"
-	    "[-x policy] [-z nframes]\n",
+	    "[-w flag] [-x policy] [-z nframes]\n",
 	    stderr);
 }
 
@@ -512,8 +513,9 @@ aucat_main(int argc, char **argv)
 	cd->bufsz = 0;
 	cd->round = 0;
 	cd->hold = 1;
+	cd->autovol = 1;
 
-	while ((c = getopt(argc, argv, "a:dnb:c:C:e:r:h:x:v:i:o:f:m:luq:s:U:L:t:j:z:")) != -1) {
+	while ((c = getopt(argc, argv, "a:w:dnb:c:C:e:r:h:x:v:i:o:f:m:luq:s:U:L:t:j:z:")) != -1) {
 		switch (c) {
 		case 'd':
 #ifdef DEBUG
@@ -593,6 +595,9 @@ aucat_main(int argc, char **argv)
 		case 'a':
 			cd->hold = opt_onoff();
 			break;
+		case 'w':
+			cd->autovol = opt_onoff();
+			break;
 		case 'q':
 			cfmid_add(&cd->mids, optarg);
 			break;
@@ -731,7 +736,7 @@ aucat_main(int argc, char **argv)
 		} else {
 			d = dev_new_sio(cd->path, cd->mode | MODE_MIDIMASK,
 			    &cd->ipar, &cd->opar, cd->bufsz, cd->round,
-			    cd->hold);
+			    cd->hold, cd->autovol);
 		}
 		if (d == NULL)
 			errx(1, "%s: can't open device", cd->path);
diff --git a/aucat/dev.c b/aucat/dev.c
index 2c4cfce..fcf146a 100644
--- a/aucat/dev.c
+++ b/aucat/dev.c
@@ -114,7 +114,7 @@ struct dev *dev_list = NULL;
 struct dev *
 dev_new_sio(char *path,
     unsigned mode, struct aparams *dipar, struct aparams *dopar,
-    unsigned bufsz, unsigned round, unsigned hold)
+    unsigned bufsz, unsigned round, unsigned hold, unsigned autovol)
 {
 	struct dev *d;
 
@@ -132,6 +132,7 @@ dev_new_sio(char *path,
 	d->reqbufsz = bufsz;
 	d->reqround = round;
 	d->hold = hold;
+	d->autovol = autovol;
 	d->pstate = DEV_CLOSED;
 	d->next = dev_list;
 	dev_list = d;
@@ -299,7 +300,7 @@ dev_open(struct dev *d)
 	 * Create mixer, demuxer and monitor
 	 */
 	if (d->mode & MODE_PLAY) {
-		d->mix = mix_new("play", d->bufsz, d->round);
+		d->mix = mix_new("play", d->bufsz, d->round, d->autovol);
 		d->mix->refs++;
 		d->mix->u.mix.ctl = d->midi;
 	}
diff --git a/aucat/dev.h b/aucat/dev.h
index 58ad1bd..193a8dc 100644
--- a/aucat/dev.h
+++ b/aucat/dev.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dev.h,v 1.27 2010/07/06 01:12:45 ratchov Exp $	*/
+/*	$OpenBSD$	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -34,6 +34,7 @@ struct dev {
 	unsigned reqround;			/* block size */
 	unsigned reqrate;			/* sample rate */
 	unsigned hold;				/* hold the device open ? */
+	unsigned autovol;			/* auto adjust playvol ? */
 	unsigned refcnt;			/* number of openers */
 #define DEV_CLOSED	0			/* closed */
 #define DEV_INIT	1			/* stopped */
@@ -64,7 +65,8 @@ void dev_drain(struct dev *);
 struct dev *dev_new_thru(void);
 struct dev *dev_new_loop(struct aparams *, struct aparams *, unsigned);
 struct dev *dev_new_sio(char *, unsigned, 
-    struct aparams *, struct aparams *, unsigned, unsigned, unsigned);
+    struct aparams *, struct aparams *,
+    unsigned, unsigned, unsigned, unsigned);
 int  dev_thruadd(struct dev *, char *, int, int);
 void dev_midiattach(struct dev *, struct abuf *, struct abuf *);
 unsigned dev_roundof(struct dev *, unsigned);