diff --git a/ai-hub/app/app.py b/ai-hub/app/app.py
index a6ec166..dced2c7 100644
--- a/ai-hub/app/app.py
+++ b/ai-hub/app/app.py
@@ -120,10 +120,8 @@
     services.with_rag_service(retrievers=retrievers)
     services.with_document_service(vector_store=vector_store)
     
-    if stt_provider:
-        services.with_service("stt_service", service=STTService(stt_provider=stt_provider))
-    if tts_provider:
-        services.with_service("tts_service", service=TTSService(tts_provider=tts_provider))
+    services.with_service("stt_service", service=STTService(stt_provider=stt_provider))
+    services.with_service("tts_service", service=TTSService(tts_provider=tts_provider))
         
     services.with_service("workspace_service", service=WorkspaceService())
     services.with_service("session_service", service=SessionService())
diff --git a/ai-hub/app/core/services/stt.py b/ai-hub/app/core/services/stt.py
index 7325f2d..fed6830 100644
--- a/ai-hub/app/core/services/stt.py
+++ b/ai-hub/app/core/services/stt.py
@@ -10,9 +10,9 @@
     Service class for transcribing audio into text using an STT provider.
     """
 
-    def __init__(self, stt_provider: STTProvider):
+    def __init__(self, stt_provider: STTProvider = None):
         """
-        Initializes the STTService with a concrete STT provider.
+        Initializes the STTService with an optional STT provider.
         """
         self.default_stt_provider = stt_provider
 
@@ -21,6 +21,8 @@
         Transcribes the provided audio bytes into text using the STT provider.
         """
         provider = provider_override or self.default_stt_provider
+        if not provider:
+            raise HTTPException(status_code=400, detail="No active STT provider is configured.")
         logger.info(f"Starting transcription for audio data ({len(audio_bytes)} bytes).")
 
         if not audio_bytes:
diff --git a/ai-hub/app/core/services/tts.py b/ai-hub/app/core/services/tts.py
index d9b5929..5711d88 100644
--- a/ai-hub/app/core/services/tts.py
+++ b/ai-hub/app/core/services/tts.py
@@ -33,7 +33,7 @@
     
     MAX_CHUNK_SIZE = int(os.getenv("TTS_MAX_CHUNK_SIZE", 500))
 
-    def __init__(self, tts_provider: TTSProvider):
+    def __init__(self, tts_provider: TTSProvider = None):
         self.default_tts_provider = tts_provider
 
     async def _split_text_into_chunks(self, text: str) -> list[str]:
@@ -69,6 +69,8 @@
     async def _generate_pcm_chunks(self, text: str, provider_override: TTSProvider = None) -> AsyncGenerator[bytes, None]:
         chunks = await self._split_text_into_chunks(text)
         provider = provider_override or self.default_tts_provider
+        if not provider:
+            raise HTTPException(status_code=400, detail="No active TTS provider is configured.")
         
         for i, chunk in enumerate(chunks):
             logger.info(f"Generating PCM for chunk {i+1}/{len(chunks)}: '{chunk[:30]}...'")
@@ -97,6 +99,8 @@
         chunks = await self._split_text_into_chunks(text)
         semaphore = asyncio.Semaphore(3)  # Limit concurrency to 3 requests
         provider = provider_override or self.default_tts_provider
+        if not provider:
+            raise HTTPException(status_code=400, detail="No active TTS provider is configured.")
 
         async def generate_with_limit(chunk):
             retries = 3