diff --git a/aucat/aucat.1 b/aucat/aucat.1
index ea53e98..4629a86 100644
--- a/aucat/aucat.1
+++ b/aucat/aucat.1
@@ -111,6 +111,9 @@ The buffer size of the audio device in frames.
 A frame consists of one sample for each channel in the stream.
 This is the number of frames that will be buffered before being played
 and thus controls the playback latency.
+The default is 7680 or twice the block size
+.Pq Fl z ,
+if the block size is set.
 .It Xo
 .Fl C Ar min : Ns Ar max ,
 .Fl c Ar min : Ns Ar max
@@ -244,7 +247,7 @@ Control (MMC) slave mode
 .Pq Fl t .
 .It Fl r Ar rate
 Sample rate in Hertz of the stream.
-The default is 44100Hz.
+The default is 48000.
 .It Fl s Ar name
 Add
 .Ar name
@@ -354,8 +357,11 @@ option,
 and MTC is used for synchronization, the clock
 resolution must be 96, 100 or 120 ticks per second for maximum
 accuracy.
-For instance, 120 ticks per second at 48000Hz corresponds
-to a 400 frame block size.
+For instance, 100 ticks per second at 48000Hz corresponds
+to a 480 frame block size.
+The default is 960 or half of the buffer size
+.Pq Fl b ,
+if the buffer size is set.
 .El
 .Pp
 On the command line,
diff --git a/aucat/aucat.c b/aucat/aucat.c
index f370d6a..0423296 100644
--- a/aucat/aucat.c
+++ b/aucat/aucat.c
@@ -63,14 +63,21 @@
  * sample rate if no ``-r'' is used
  */
 #ifndef DEFAULT_RATE
-#define DEFAULT_RATE	44100
+#define DEFAULT_RATE	48000
 #endif
 
 /*
- * block size if no ``-z'' is used
+ * block size if neither ``-z'' nor ``-b'' is used
  */
 #ifndef DEFAULT_ROUND
-#define DEFAULT_ROUND	(44100 / 15)
+#define DEFAULT_ROUND	960
+#endif
+
+/*
+ * buffer size if neither ``-z'' nor ``-b'' is used
+ */
+#ifndef DEFAULT_BUFSZ
+#define DEFAULT_BUFSZ	7860
 #endif
 
 /*
@@ -345,12 +352,13 @@ mkdev(char *path, int mode, int bufsz, int round, int hold, int autovol)
 			return dev_list;
 		path = "default";
 	}
-	if (!bufsz) {
-		if (!round)
-			round = DEFAULT_ROUND;
-		bufsz = round * 4;
+	if (!bufsz && !round) {
+		round = DEFAULT_ROUND;
+		bufsz = DEFAULT_BUFSZ;
+	} else if (!bufsz) {
+		bufsz = round * 2;
 	} else if (!round)
-		round = bufsz / 4;
+		round = bufsz / 2;
 	d = dev_new(path, mode, bufsz, round, hold, autovol);
 	if (d == NULL)
 		exit(1);
diff --git a/aucat/dev.c b/aucat/dev.c
index 96f83dd..a9ca31c 100644
--- a/aucat/dev.c
+++ b/aucat/dev.c
@@ -283,7 +283,7 @@ dev_open(struct dev *d)
 	else
 		d->opar.rate = d->ipar.rate;
 	if (d->opar.rate == 0)
-		d->opar.rate = d->ipar.rate = 44100; /* XXX */
+		d->opar.rate = d->ipar.rate = 48000; /* XXX */
 
 	if (d->mode & MODE_THRU)
 		d->mode &= ~MODE_AUDIOMASK;