diff --git a/src/main/acio/acio.h b/src/main/acio/acio.h
index 040f308..0636e95 100644
--- a/src/main/acio/acio.h
+++ b/src/main/acio/acio.h
@@ -11,6 +11,7 @@
 #include "acio/kfca.h"
 #include "acio/mdxf.h"
 #include "acio/panb.h"
+#include "acio/rvol.h"
 
 #define AC_IO_SOF 0xAA
 #define AC_IO_ESCAPE 0xFF
@@ -88,6 +89,9 @@ struct ac_io_message {
 
                 struct ac_io_hdxs_output hdxs_output;
 
+                struct ac_io_rvol_poll_in rvol_poll_in;
+                struct ac_io_rvol_poll_out rvol_poll_out;
+
                 struct ac_io_mdxf_poll_in mdxf_poll_in;
                 struct ac_io_mdxf_light_out mdxf_light_out;
             };
diff --git a/src/main/acio/rvol.h b/src/main/acio/rvol.h
new file mode 100644
index 0000000..ff9c9f9
--- /dev/null
+++ b/src/main/acio/rvol.h
@@ -0,0 +1,74 @@
+#ifndef AC_IO_RVOL_H
+#define AC_IO_RVOL_H
+
+#include <stdint.h>
+
+// technically RVOL also can poll with CMD 0x0113
+// but museca never uses this (it's controlled by if the watchdog is on/off)
+#define AC_IO_CMD_RVOL_POLL 0x0112
+#define AC_IO_CMD_RVOL_SET_EXPAND_MODE 0x0114
+#define AC_IO_CMD_RVOL_AMP_CONTROL 0x0128
+
+#pragma pack(push, 1)
+
+struct ac_io_rvol_buttons_1 {
+    uint8_t unk0 : 1;
+    uint8_t unk1 : 1;
+    uint8_t spinner_4 : 1;
+    uint8_t pedal : 1;
+    uint8_t spinner_5 : 1;
+    uint8_t unk5 : 1;
+    uint8_t unk6 : 1;
+    uint8_t unk7 : 1;
+};
+
+struct ac_io_rvol_buttons_2 {
+    uint8_t spinner_2 : 1;
+    uint8_t unk1 : 1;
+    uint8_t unk2 : 1;
+    uint8_t spinner_1 : 1;
+    uint8_t unk4 : 1;
+    uint8_t unk5 : 1;
+    uint8_t unk6 : 1;
+    uint8_t unk7 : 1;
+};
+
+struct ac_io_rvol_buttons_3 {
+    uint8_t unk0 : 1;
+    uint8_t unk1 : 1;
+    uint8_t unk2 : 1;
+    uint8_t spinner_3 : 1;
+    uint8_t unk4 : 1;
+    uint8_t unk5 : 1;
+    uint8_t unk6 : 1;
+    uint8_t unk7 : 1;
+};
+
+struct ac_io_rvol_poll_in {
+    uint8_t unk_0;
+    struct ac_io_rvol_buttons_1 buttons_1;
+    uint8_t unk_2_8[7];
+    struct ac_io_rvol_buttons_2 buttons_2;
+    uint8_t unk_10;
+    struct ac_io_rvol_buttons_3 buttons_3;
+    uint8_t unk_12_15[4];
+    uint8_t spinners[5];
+    uint8_t unk_21_22[2];
+};
+
+struct light_rgb {
+    uint8_t r;
+    uint8_t g;
+    uint8_t b;
+};
+
+struct ac_io_rvol_poll_out {
+    uint8_t unk0_3[4];
+    struct light_rgb spinner[5];
+    struct light_rgb title;
+    uint8_t unk22_31[10];
+};
+
+#pragma pack(pop)
+
+#endif