diff --git a/app/helper/voice.py b/app/helper/voice.py
index 59b132e6..af633eb1 100644
--- a/app/helper/voice.py
+++ b/app/helper/voice.py
@@ -13,7 +13,7 @@ from app.log import logger
 class VoiceProvider(ABC):
     """语音 provider 抽象层。"""
 
-    MAX_TRANSCRIBE_BYTES = 25 * 1024 * 1024
+    MAX_TRANSCRIBE_BYTES = 10 * 1024 * 1024
 
     @property
     @abstractmethod
@@ -49,10 +49,8 @@ class OpenAIVoiceProvider(VoiceProvider):
         provider = settings.AI_VOICE_PROVIDER or "openai"
         return provider.strip().lower()
 
-    @staticmethod
-    def _resolve_credentials(mode: str) -> tuple[Optional[str], Optional[str]]:
-        mode = mode.lower()
-        provider = OpenAIVoiceProvider._resolve_provider_name()
+    def _resolve_credentials(self) -> tuple[Optional[str], Optional[str]]:
+        provider = self._resolve_provider_name()
         api_key = settings.AI_VOICE_API_KEY
         base_url = settings.AI_VOICE_BASE_URL
 
@@ -69,17 +67,17 @@ class OpenAIVoiceProvider(VoiceProvider):
     def _get_client(self, mode: str):
         from openai import OpenAI
 
-        api_key, base_url = self._resolve_credentials(mode)
+        api_key, base_url = self._resolve_credentials()
         if not api_key:
             raise ValueError(f"{mode.upper()} provider 未配置 API Key")
         return OpenAI(api_key=api_key, base_url=base_url, max_retries=3)
 
     def is_available_for_stt(self) -> bool:
-        api_key, _ = self._resolve_credentials("stt")
+        api_key, _ = self._resolve_credentials()
         return bool(api_key)
 
     def is_available_for_tts(self) -> bool:
-        api_key, _ = self._resolve_credentials("tts")
+        api_key, _ = self._resolve_credentials()
         return bool(api_key)
 
     def transcribe_bytes(self, content: bytes, filename: str = "input.ogg") -> Optional[str]:
@@ -144,14 +142,12 @@ class VoiceHelper:
         """音频输入输出总开关，以显式配置为准。"""
         return bool(settings.LLM_SUPPORT_AUDIO_INPUT_OUTPUT)
 
-    @staticmethod
-    def _resolve_provider_name(mode: str) -> str:
-        del mode
-        return OpenAIVoiceProvider._resolve_provider_name()
+    def _resolve_provider_name(self) -> str:
+        return self._resolve_provider_name()
 
     @classmethod
     def get_provider(cls, mode: str) -> Optional[VoiceProvider]:
-        provider_name = cls._resolve_provider_name(mode)
+        provider_name = cls._resolve_provider_name()
         provider = cls._providers.get(provider_name)
         if provider:
             return provider