diff --git a/libsndio/sioctl_sun.c b/libsndio/sioctl_sun.c
index 119aec8..a050067 100644
--- a/libsndio/sioctl_sun.c
+++ b/libsndio/sioctl_sun.c
@@ -224,6 +224,7 @@ scanvol(struct sioctl_sun_hdl *hdl, struct wskbd_vol *vol)
 	int i, val;
 
 	memset(&desc, 0, sizeof(struct sioctl_desc));
+	strlcpy(desc.group, "hw", SIOCTL_NAMEMAX);
 	if (vol->level_idx >= 0) {
 		ctrl.dev = vol->level_idx;
 		ctrl.type = AUDIO_MIXER_VALUE;
diff --git a/sndiod/dev_sioctl.c b/sndiod/dev_sioctl.c
index b4d1e65..af61c9c 100644
--- a/sndiod/dev_sioctl.c
+++ b/sndiod/dev_sioctl.c
@@ -53,7 +53,7 @@ dev_sioctl_ondesc(void *arg, struct sioctl_desc *desc, int val)
 {
 #define GROUP_PREFIX		"dev"
 #define GROUP_PREFIX_LEN	(sizeof(GROUP_PREFIX))
-	char group[CTL_NAMEMAX];
+	char group_buf[CTL_NAMEMAX], *group;
 	struct dev *d = arg;
 	size_t len;
 	int addr;
@@ -62,13 +62,22 @@ dev_sioctl_ondesc(void *arg, struct sioctl_desc *desc, int val)
 		return;
 	addr = CTLADDR_END + desc->addr;
 	dev_rmctl(d, addr);
-	if (desc->group[0] != 0) {
-		len = snprintf(group, CTL_NAMEMAX,
+
+	/*
+	 * prefix group names we use (top-level and "app") with "dev."
+	 * to ensure that all controls have unique names when multiple
+	 * sndiod's are chained
+	 */
+	if (desc->group[0] == 0)
+		group = GROUP_PREFIX;
+	else if (strcmp(desc->group, "app") == 0) {
+		group = group_buf;
+		len = snprintf(group_buf, CTL_NAMEMAX,
 		    GROUP_PREFIX ".%s", desc->group);
 		if (len >= CTL_NAMEMAX)
 			return;
 	} else
-		strlcpy(group, GROUP_PREFIX, CTL_NAMEMAX);
+		group = desc->group;
 
 	dev_addctl(d, group, desc->type, addr,
 	    desc->chan0.str, desc->chan0.unit, desc->func,