diff --git a/sw_usb_audio/app_usb_aud_phaten_golden_6ch/src/extensions/audiohw.xc b/sw_usb_audio/app_usb_aud_phaten_golden_6ch/src/extensions/audiohw.xc
index c50e459..10e5aad 100644
--- a/sw_usb_audio/app_usb_aud_phaten_golden_6ch/src/extensions/audiohw.xc
+++ b/sw_usb_audio/app_usb_aud_phaten_golden_6ch/src/extensions/audiohw.xc
@@ -79,13 +79,13 @@ unsigned g_mute_state = 0;
 unsigned g_mute_state_old = 1;
 unsigned g_unmute_dac_state, g_unmute_time,  g_format_time;
 // 改动原因：DAC音量协议扩展到49级（0~48），默认值同步到最大级48。
-unsigned g_volume_level = 48, g_saved_volume_level = 48;
+unsigned g_volume_level = 24, g_saved_volume_level = 24;
 unsigned g_request_volume_set = 0;
 unsigned g_init_saved_settings = 0;
 unsigned g_host_volume = 0x0;
 unsigned g_last_volume_level = 0xFF;  // 上次已上报的音量级别，0xFF表示初始化未完成
 // 改动原因：麦克风HID等级调整为49级（0~48），并将最大模拟增益限制到24dB。
-unsigned g_mic_volume_level = 48;     // 麦克风音量等级（0=mute, 1~48=0~24dB，0.5dB/级）
+unsigned g_mic_volume_level = 24;     // 麦克风音量等级（0=mute, 1~48=0~24dB，0.5dB/级）
 unsigned g_request_mic_volume_set = 0;
 unsigned g_last_mic_volume_level = 0xFF;  // 上次已上报的麦克风增益级别，0xFF表示初始化未完成
 unsigned g_dnr_strength = 100;            // AI降噪强度HID值（1-100=档位，步进1；100→-200dB最强；关断由g_dnr_on控制，此处不再用0表示强度）
@@ -240,7 +240,8 @@ void board_setup()
 // 改动原因：协议层改为49级(0~48)，硬件仍是1dB步进；通过“2个等级映射1dB”实现24dB上限。
 #define MIC_HID_LEVEL_MIN 0
 #define MIC_HID_LEVEL_MAX 48
-#define MIC_HID_LEVEL_DEFAULT 44   // 约22dB，保持原默认听感接近
+#define MIC_HID_LEVEL_DEFAULT 24  // 24dB，保持原默认听感接近
+#define DAC_HID_LEVEL_DEFAULT 24  // 24dB，保持原默认听感接近
 
 #define NAU88L21_PGA_GAIN_REG_MIN_USED_VALUE 0x0    // 0=mute
 #define NAU88L21_PGA_GAIN_REG_MAX_VALUE 0x18        // 24dB上限
@@ -510,7 +511,7 @@ void button_task(chanend c_hidSendData, chanend cc_mic_level, chanend c_uac_vol,
     int codec_adc_pga_gain_reg_value = MIC_HID_LEVEL_DEFAULT;
 
     // 改动原因：默认监听音量从旧30级体系迁移到49级体系，保持中高音量默认值。
-    int dac_level = 30;
+    int dac_level = DAC_HID_LEVEL_DEFAULT;
 
     // mic endcoder 变量
     uint8_t prev_encode_input1 = 0;