diff --git a/share/man/man4/snd_hdsp.4 b/share/man/man4/snd_hdsp.4
--- a/share/man/man4/snd_hdsp.4
+++ b/share/man/man4/snd_hdsp.4
@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 28, 2024
+.Dd October 28, 2024
 .Dt SND_HDSP 4
 .Os
 .Sh NAME
@@ -134,6 +134,28 @@
 audio).
 .El
 .Pp
+The following tunables are applicable to HDSP 9632 devices only:
+.Bl -tag -width indent
+.It Va dev.hdsp.0.input_level
+Select the sensitivity of the analog line input.
+Available reference levels for the input signal are
+.Ql LowGain ,
+.Ql +4dBu
+and
+.Ql -10dBV .
+.It Va dev.hdsp.0.output_level
+Select the gain level of the analog line output.
+Available reference levels for the output signal are
+.Ql HighGain ,
+.Ql +4dBu
+and
+.Ql -10dBV .
+.It Va dev.hdsp.0.phones_level
+Adjust the gain level of the phones output, separately from the analog line
+output.
+The signal can be lowered by 6 or 12 dB.
+.El
+.Pp
 Where appropriate these sysctl values are modeled after official RME software on
 other platforms, and adopt their terminology.
 Consult the RME user manuals for additional information.
diff --git a/sys/dev/sound/pci/hdsp.h b/sys/dev/sound/pci/hdsp.h
--- a/sys/dev/sound/pci/hdsp.h
+++ b/sys/dev/sound/pci/hdsp.h
@@ -80,39 +80,47 @@
 #define	HDSP_LAT_BYTES_MIN		(32 * 4)
 #define	hdsp_encode_latency(x)		(((x)<<1) & HDSP_LAT_MASK)
 
-/* Gain */
-#define	HDSP_ADGain0			(1 << 25)
-#define	HDSP_ADGain1			(1 << 26)
-#define	HDSP_DAGain0			(1 << 27)
-#define	HDSP_DAGain1			(1 << 28)
-#define	HDSP_PhoneGain0			(1 << 29)
-#define	HDSP_PhoneGain1			(1 << 30)
-
-#define	HDSP_ADGainMask			(HDSP_ADGain0 | HDSP_ADGain1)
-#define	HDSP_ADGainMinus10dBV		(HDSP_ADGainMask)
-#define	HDSP_ADGainPlus4dBu		(HDSP_ADGain0)
-#define	HDSP_ADGainLowGain		0
-
-#define	HDSP_DAGainMask			(HDSP_DAGain0 | HDSP_DAGain1)
-#define	HDSP_DAGainHighGain		(HDSP_DAGainMask)
-#define	HDSP_DAGainPlus4dBu		(HDSP_DAGain0)
-#define	HDSP_DAGainMinus10dBV		0
-
-#define	HDSP_PhoneGainMask		(HDSP_PhoneGain0|HDSP_PhoneGain1)
-#define	HDSP_PhoneGain0dB		HDSP_PhoneGainMask
-#define	HDSP_PhoneGainMinus6dB		(HDSP_PhoneGain0)
-#define	HDSP_PhoneGainMinus12dB		0
-
-/* Settings */
+/* Register addresses */
 #define	HDSP_RESET_POINTER		0
 #define	HDSP_CONTROL_REG		64
 #define	HDSP_CONTROL2_REG		256
 #define	HDSP_STATUS_REG			0
 #define	HDSP_STATUS2_REG		192
 
+/* Control register flags */
 #define	HDSP_ENABLE			(1 << 0)
 #define	HDSP_CONTROL_SPDIF_COAX		(1 << 14)
 #define	HDSP_CONTROL_LINE_OUT		(1 << 24)
+#define	HDSP_CONTROL_INPUT_GAIN0	(1 << 25)
+#define	HDSP_CONTROL_INPUT_GAIN1	(1 << 26)
+#define	HDSP_CONTROL_OUTPUT_GAIN0	(1 << 27)
+#define	HDSP_CONTROL_OUTPUT_GAIN1	(1 << 28)
+#define	HDSP_CONTROL_PHONES_GAIN0	(1 << 29)
+#define	HDSP_CONTROL_PHONES_GAIN1	(1 << 30)
+
+/* Analog input gain level */
+#define	HDSP_INPUT_LEVEL_MASK		(HDSP_CONTROL_INPUT_GAIN0 | \
+					HDSP_CONTROL_INPUT_GAIN1)
+#define	HDSP_INPUT_LEVEL_LOWGAIN	0
+#define	HDSP_INPUT_LEVEL_PLUS4DBU	(HDSP_CONTROL_INPUT_GAIN0)
+#define	HDSP_INPUT_LEVEL_MINUS10DBV	(HDSP_CONTROL_INPUT_GAIN0 | \
+					HDSP_CONTROL_INPUT_GAIN1)
+
+/* Analog output gain level */
+#define	HDSP_OUTPUT_LEVEL_MASK		(HDSP_CONTROL_OUTPUT_GAIN0 | \
+					HDSP_CONTROL_OUTPUT_GAIN1)
+#define	HDSP_OUTPUT_LEVEL_MINUS10DBV	0
+#define	HDSP_OUTPUT_LEVEL_PLUS4DBU	(HDSP_CONTROL_OUTPUT_GAIN0)
+#define	HDSP_OUTPUT_LEVEL_HIGHGAIN	(HDSP_CONTROL_OUTPUT_GAIN0 | \
+					HDSP_CONTROL_OUTPUT_GAIN1)
+
+/* Phones output gain level */
+#define	HDSP_PHONES_LEVEL_MASK		(HDSP_CONTROL_PHONES_GAIN0 | \
+					HDSP_CONTROL_PHONES_GAIN1)
+#define	HDSP_PHONES_LEVEL_MINUS12DB	0
+#define	HDSP_PHONES_LEVEL_MINUS6DB	(HDSP_CONTROL_PHONES_GAIN0)
+#define	HDSP_PHONES_LEVEL_0DB		(HDSP_CONTROL_PHONES_GAIN0 | \
+					HDSP_CONTROL_PHONES_GAIN1)
 
 /* Interrupts */
 #define	HDSP_AUDIO_IRQ_PENDING		(1 << 0)
diff --git a/sys/dev/sound/pci/hdsp.c b/sys/dev/sound/pci/hdsp.c
--- a/sys/dev/sound/pci/hdsp.c
+++ b/sys/dev/sound/pci/hdsp.c
@@ -231,6 +231,198 @@
 	hdsp_write_4(sc, HDSP_PAGE_ADDR_BUF_IN, raddr);
 }
 
+static const char *
+hdsp_control_input_level(uint32_t control)
+{
+	switch (control & HDSP_INPUT_LEVEL_MASK) {
+	case HDSP_INPUT_LEVEL_LOWGAIN:
+		return ("LowGain");
+	case HDSP_INPUT_LEVEL_PLUS4DBU:
+		return ("+4dBu");
+	case HDSP_INPUT_LEVEL_MINUS10DBV:
+		return ("-10dBV");
+	default:
+		return (NULL);
+	}
+}
+
+static int
+hdsp_sysctl_input_level(SYSCTL_HANDLER_ARGS)
+{
+	struct sc_info *sc;
+	const char *label;
+	char buf[16] = "invalid";
+	int error;
+	uint32_t control;
+
+	sc = oidp->oid_arg1;
+
+	/* Only available on HDSP 9632. */
+	if (sc->type != HDSP_9632)
+		return (ENXIO);
+
+	/* Extract current input level from control register. */
+	control = sc->ctrl_register & HDSP_INPUT_LEVEL_MASK;
+	label = hdsp_control_input_level(control);
+	if (label != NULL)
+		strlcpy(buf, label, sizeof(buf));
+
+	/* Process sysctl string request. */
+	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+
+	/* Find input level matching the sysctl string. */
+	label = hdsp_control_input_level(HDSP_INPUT_LEVEL_LOWGAIN);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_INPUT_LEVEL_LOWGAIN;
+	label = hdsp_control_input_level(HDSP_INPUT_LEVEL_PLUS4DBU);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_INPUT_LEVEL_PLUS4DBU;
+	label = hdsp_control_input_level(HDSP_INPUT_LEVEL_MINUS10DBV);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_INPUT_LEVEL_MINUS10DBV;
+
+	/* Set input level in control register. */
+	control &= HDSP_INPUT_LEVEL_MASK;
+	if (control != (sc->ctrl_register & HDSP_INPUT_LEVEL_MASK)) {
+		snd_mtxlock(sc->lock);
+		sc->ctrl_register &= ~HDSP_INPUT_LEVEL_MASK;
+		sc->ctrl_register |= control;
+		hdsp_write_4(sc, HDSP_CONTROL_REG, sc->ctrl_register);
+		snd_mtxunlock(sc->lock);
+	}
+	return (0);
+}
+
+static const char *
+hdsp_control_output_level(uint32_t control)
+{
+	switch (control & HDSP_OUTPUT_LEVEL_MASK) {
+	case HDSP_OUTPUT_LEVEL_MINUS10DBV:
+		return ("-10dBV");
+	case HDSP_OUTPUT_LEVEL_PLUS4DBU:
+		return ("+4dBu");
+	case HDSP_OUTPUT_LEVEL_HIGHGAIN:
+		return ("HighGain");
+	default:
+		return (NULL);
+	}
+}
+
+static int
+hdsp_sysctl_output_level(SYSCTL_HANDLER_ARGS)
+{
+	struct sc_info *sc;
+	const char *label;
+	char buf[16] = "invalid";
+	int error;
+	uint32_t control;
+
+	sc = oidp->oid_arg1;
+
+	/* Only available on HDSP 9632. */
+	if (sc->type != HDSP_9632)
+		return (ENXIO);
+
+	/* Extract current output level from control register. */
+	control = sc->ctrl_register & HDSP_OUTPUT_LEVEL_MASK;
+	label = hdsp_control_output_level(control);
+	if (label != NULL)
+		strlcpy(buf, label, sizeof(buf));
+
+	/* Process sysctl string request. */
+	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+
+	/* Find output level matching the sysctl string. */
+	label = hdsp_control_output_level(HDSP_OUTPUT_LEVEL_MINUS10DBV);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_OUTPUT_LEVEL_MINUS10DBV;
+	label = hdsp_control_output_level(HDSP_OUTPUT_LEVEL_PLUS4DBU);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_OUTPUT_LEVEL_PLUS4DBU;
+	label = hdsp_control_output_level(HDSP_OUTPUT_LEVEL_HIGHGAIN);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_OUTPUT_LEVEL_HIGHGAIN;
+
+	/* Set output level in control register. */
+	control &= HDSP_OUTPUT_LEVEL_MASK;
+	if (control != (sc->ctrl_register & HDSP_OUTPUT_LEVEL_MASK)) {
+		snd_mtxlock(sc->lock);
+		sc->ctrl_register &= ~HDSP_OUTPUT_LEVEL_MASK;
+		sc->ctrl_register |= control;
+		hdsp_write_4(sc, HDSP_CONTROL_REG, sc->ctrl_register);
+		snd_mtxunlock(sc->lock);
+	}
+	return (0);
+}
+
+static const char *
+hdsp_control_phones_level(uint32_t control)
+{
+	switch (control & HDSP_PHONES_LEVEL_MASK) {
+	case HDSP_PHONES_LEVEL_MINUS12DB:
+		return ("-12dB");
+	case HDSP_PHONES_LEVEL_MINUS6DB:
+		return ("-6dB");
+	case HDSP_PHONES_LEVEL_0DB:
+		return ("0dB");
+	default:
+		return (NULL);
+	}
+}
+
+static int
+hdsp_sysctl_phones_level(SYSCTL_HANDLER_ARGS)
+{
+	struct sc_info *sc;
+	const char *label;
+	char buf[16] = "invalid";
+	int error;
+	uint32_t control;
+
+	sc = oidp->oid_arg1;
+
+	/* Only available on HDSP 9632. */
+	if (sc->type != HDSP_9632)
+		return (ENXIO);
+
+	/* Extract current phones level from control register. */
+	control = sc->ctrl_register & HDSP_PHONES_LEVEL_MASK;
+	label = hdsp_control_phones_level(control);
+	if (label != NULL)
+		strlcpy(buf, label, sizeof(buf));
+
+	/* Process sysctl string request. */
+	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+
+	/* Find phones level matching the sysctl string. */
+	label = hdsp_control_phones_level(HDSP_PHONES_LEVEL_MINUS12DB);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_PHONES_LEVEL_MINUS12DB;
+	label = hdsp_control_phones_level(HDSP_PHONES_LEVEL_MINUS6DB);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_PHONES_LEVEL_MINUS6DB;
+	label = hdsp_control_phones_level(HDSP_PHONES_LEVEL_0DB);
+	if (strncasecmp(buf, label, sizeof(buf)) == 0)
+		control = HDSP_PHONES_LEVEL_0DB;
+
+	/* Set phones level in control register. */
+	control &= HDSP_PHONES_LEVEL_MASK;
+	if (control != (sc->ctrl_register & HDSP_PHONES_LEVEL_MASK)) {
+		snd_mtxlock(sc->lock);
+		sc->ctrl_register &= ~HDSP_PHONES_LEVEL_MASK;
+		sc->ctrl_register |= control;
+		hdsp_write_4(sc, HDSP_CONTROL_REG, sc->ctrl_register);
+		snd_mtxunlock(sc->lock);
+	}
+	return (0);
+}
+
 static int
 hdsp_sysctl_sample_rate(SYSCTL_HANDLER_ARGS)
 {
@@ -606,6 +798,14 @@
 	sc->ctrl_register &= ~HDSP_CONTROL_LINE_OUT;
 	sc->ctrl_register |= HDSP_CONTROL_LINE_OUT;
 
+	/* Default gain levels. */
+	sc->ctrl_register &= ~HDSP_INPUT_LEVEL_MASK;
+	sc->ctrl_register |= HDSP_INPUT_LEVEL_LOWGAIN;
+	sc->ctrl_register &= ~HDSP_OUTPUT_LEVEL_MASK;
+	sc->ctrl_register |= HDSP_OUTPUT_LEVEL_MINUS10DBV;
+	sc->ctrl_register &= ~HDSP_PHONES_LEVEL_MASK;
+	sc->ctrl_register |= HDSP_PHONES_LEVEL_MINUS12DB;
+
 	hdsp_write_4(sc, HDSP_CONTROL_REG, sc->ctrl_register);
 
 	if (sc->type == HDSP_9652)
@@ -732,6 +932,26 @@
 	    sc, 0, hdsp_sysctl_sample_rate, "A",
 	    "Force sample rate (32000, 44100, 48000, ... 192000)");
 
+	if (sc->type == HDSP_9632) {
+		SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
+		    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
+		    "phones_level", CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,
+		    sc, 0, hdsp_sysctl_phones_level, "A",
+		    "Phones output level ('0dB', '-6dB', '-12dB')");
+
+		SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
+		    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
+		    "output_level", CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,
+		    sc, 0, hdsp_sysctl_output_level, "A",
+		    "Analog output level ('HighGain', '+4dBU', '-10dBV')");
+
+		SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
+		    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
+		    "input_level", CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,
+		    sc, 0, hdsp_sysctl_input_level, "A",
+		    "Analog input level ('LowGain', '+4dBU', '-10dBV')");
+	}
+
 	return (bus_generic_attach(dev));
 }