diff --git a/public/sounds/default.wav b/public/sounds/default.wav
index 59238b1b..e69de29b 100644
Binary files a/public/sounds/default.wav and b/public/sounds/default.wav differ
diff --git a/public/sounds/push_notification.wav b/public/sounds/push_notification.wav
index 59238b1b..e69de29b 100644
Binary files a/public/sounds/push_notification.wav and b/public/sounds/push_notification.wav differ
diff --git a/public/sounds/sam_voice.wav b/public/sounds/sam_voice.wav
deleted file mode 100644
index 59238b1b..00000000
Binary files a/public/sounds/sam_voice.wav and /dev/null differ
diff --git a/src/components/settings/NotificationSettings/index.tsx b/src/components/settings/NotificationSettings/index.tsx
index e4d0ba9d..4aaa7739 100644
--- a/src/components/settings/NotificationSettings/index.tsx
+++ b/src/components/settings/NotificationSettings/index.tsx
@@ -29,26 +29,13 @@ import { saveNotificationSettings } from './actions';
 import { ItemSettingsDialog } from './ItemSettingsDialog';
 
 // 미리듣기 함수
-let previewAudio: HTMLAudioElement | null = null;
-
 function playPreviewSound(soundType: SoundType) {
   if (soundType === 'mute') {
     toast.info('무음으로 설정되어 있습니다.');
     return;
   }
-
-  // 이전 재생 중지
-  if (previewAudio) {
-    previewAudio.pause();
-    previewAudio = null;
-  }
-
-  const soundFile = soundType === 'sam_voice' ? 'sam_voice.wav' : 'default.wav';
-  previewAudio = new Audio(`/sounds/${soundFile}`);
-  previewAudio.play().catch(() => {
-    const soundName = soundType === 'default' ? '기본 알림음' : 'SAM 보이스';
-    toast.info(`${soundName} 미리듣기`);
-  });
+  const soundName = soundType === 'default' ? '기본 알림음' : 'SAM 보이스';
+  toast.info(`${soundName} 미리듣기`);
 }
 
 // 알림 항목 컴포넌트
diff --git a/src/components/settings/NotificationSettings/types.ts b/src/components/settings/NotificationSettings/types.ts
index c5290b53..b9b878e6 100644
--- a/src/components/settings/NotificationSettings/types.ts
+++ b/src/components/settings/NotificationSettings/types.ts
@@ -1,12 +1,33 @@
 /**
  * 알림 설정 타입 정의
  *
- * API 응답 구조: { enabled, email, soundType } per item
- * soundType: 'default' | 'sam_voice' | 'mute'
+ * ========================================
+ * [2026-01-05] 백엔드 API 수정 필요 사항
+ * ========================================
  *
- * [2026-03-18] soundType API 연동 완료
- * - API가 settings JSON 컬럼의 sound_type 키로 저장/반환
- * - 음원 파일: public/sounds/default.wav, sam_voice.wav
+ * 1. NotificationItem에 soundType 필드 추가
+ *    - 기존: { enabled: boolean, email: boolean }
+ *    - 변경: { enabled: boolean, email: boolean, soundType: 'default' | 'sam_voice' | 'mute' }
+ *
+ * 2. OrderNotificationSettings에 approvalRequest 항목 추가
+ *    - 기존: { salesOrder, purchaseOrder }
+ *    - 변경: { salesOrder, purchaseOrder, approvalRequest }
+ *
+ * 3. API 응답 예시:
+ *    {
+ *      "notice": {
+ *        "enabled": true,
+ *        "notice": { "enabled": true, "email": false, "soundType": "default" },
+ *        "event": { "enabled": true, "email": true, "soundType": "sam_voice" }
+ *      },
+ *      "order": {
+ *        "enabled": true,
+ *        "salesOrder": { ... },
+ *        "purchaseOrder": { ... },
+ *        "approvalRequest": { "enabled": false, "email": false, "soundType": "default" }  // 새로 추가
+ *      }
+ *    }
+ * ========================================
  */
 
 // 알림 소리 타입 (NEW: 2026-01-05)