diff --git a/CHANGELOG.md b/CHANGELOG.md
index a5d97473f..b6dca2848 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -93,6 +93,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fixed an issue that would cause multiple instances of the same class to behave
+  incorrectly if any of the given constructor arguments defaulted to a mutable
+  value (e.g. lists, dictionaries, objects).
+
 - Fixed an issue with `CartesiaTTSService` where `TTSTextFrame` messages weren't
   being emitted when the model was set to `sonic`. This resulted in the
   assistant context not being updated with assistant messages.
diff --git a/src/pipecat/adapters/schemas/tools_schema.py b/src/pipecat/adapters/schemas/tools_schema.py
index 5720535c5..2489e0b4d 100644
--- a/src/pipecat/adapters/schemas/tools_schema.py
+++ b/src/pipecat/adapters/schemas/tools_schema.py
@@ -5,7 +5,7 @@
 #
 
 from enum import Enum
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Optional
 
 from pipecat.adapters.schemas.function_schema import FunctionSchema
 
@@ -18,7 +18,7 @@ class ToolsSchema:
     def __init__(
         self,
         standard_tools: List[FunctionSchema],
-        custom_tools: Dict[AdapterType, List[Dict[str, Any]]] = None,
+        custom_tools: Optional[Dict[AdapterType, List[Dict[str, Any]]]] = None,
     ) -> None:
         """
         A schema for tools that includes both standardized function schemas
diff --git a/src/pipecat/audio/turn/smart_turn/base_smart_turn.py b/src/pipecat/audio/turn/smart_turn/base_smart_turn.py
index e7f30246a..1bd187aee 100644
--- a/src/pipecat/audio/turn/smart_turn/base_smart_turn.py
+++ b/src/pipecat/audio/turn/smart_turn/base_smart_turn.py
@@ -36,10 +36,10 @@ class SmartTurnTimeoutException(Exception):
 
 class BaseSmartTurn(BaseTurnAnalyzer):
     def __init__(
-        self, *, sample_rate: Optional[int] = None, params: SmartTurnParams = SmartTurnParams()
+        self, *, sample_rate: Optional[int] = None, params: Optional[SmartTurnParams] = None
     ):
         super().__init__(sample_rate=sample_rate)
-        self._params = params
+        self._params = params or SmartTurnParams()
         # Configuration
         self._stop_ms = self._params.stop_secs * 1000  # silence threshold in ms
         # Inference state
diff --git a/src/pipecat/audio/turn/smart_turn/http_smart_turn.py b/src/pipecat/audio/turn/smart_turn/http_smart_turn.py
index 5bd3743ed..bf9f086a3 100644
--- a/src/pipecat/audio/turn/smart_turn/http_smart_turn.py
+++ b/src/pipecat/audio/turn/smart_turn/http_smart_turn.py
@@ -6,7 +6,7 @@
 
 import asyncio
 import io
-from typing import Any, Dict
+from typing import Any, Dict, Optional
 
 import aiohttp
 import numpy as np
@@ -21,12 +21,12 @@ class HttpSmartTurnAnalyzer(BaseSmartTurn):
         *,
         url: str,
         aiohttp_session: aiohttp.ClientSession,
-        headers: Dict[str, str] = {},
+        headers: Optional[Dict[str, str]] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
         self._url = url
-        self._headers = headers
+        self._headers = headers or {}
         self._aiohttp_session = aiohttp_session
 
     def _serialize_array(self, audio_array: np.ndarray) -> bytes:
diff --git a/src/pipecat/audio/vad/silero.py b/src/pipecat/audio/vad/silero.py
index a5db2a0ae..26d9368a8 100644
--- a/src/pipecat/audio/vad/silero.py
+++ b/src/pipecat/audio/vad/silero.py
@@ -105,7 +105,7 @@ class SileroOnnxModel:
 
 
 class SileroVADAnalyzer(VADAnalyzer):
-    def __init__(self, *, sample_rate: Optional[int] = None, params: VADParams = VADParams()):
+    def __init__(self, *, sample_rate: Optional[int] = None, params: Optional[VADParams] = None):
         super().__init__(sample_rate=sample_rate, params=params)
 
         logger.debug("Loading Silero VAD model...")
diff --git a/src/pipecat/audio/vad/vad_analyzer.py b/src/pipecat/audio/vad/vad_analyzer.py
index 3ca21a208..915649031 100644
--- a/src/pipecat/audio/vad/vad_analyzer.py
+++ b/src/pipecat/audio/vad/vad_analyzer.py
@@ -34,10 +34,10 @@ class VADParams(BaseModel):
 
 
 class VADAnalyzer(ABC):
-    def __init__(self, *, sample_rate: Optional[int] = None, params: VADParams):
+    def __init__(self, *, sample_rate: Optional[int] = None, params: Optional[VADParams] = None):
         self._init_sample_rate = sample_rate
         self._sample_rate = 0
-        self._params = params
+        self._params = params or VADParams()
         self._num_channels = 1
 
         self._vad_buffer = b""
diff --git a/src/pipecat/pipeline/task.py b/src/pipecat/pipeline/task.py
index 2b90d508d..6deee59f8 100644
--- a/src/pipecat/pipeline/task.py
+++ b/src/pipecat/pipeline/task.py
@@ -188,9 +188,9 @@ class PipelineTask(BaseTask):
         self,
         pipeline: BasePipeline,
         *,
-        params: PipelineParams = PipelineParams(),
-        observers: List[BaseObserver] = [],
-        clock: BaseClock = SystemClock(),
+        params: Optional[PipelineParams] = None,
+        observers: Optional[List[BaseObserver]] = None,
+        clock: Optional[BaseClock] = None,
         task_manager: Optional[BaseTaskManager] = None,
         check_dangling_tasks: bool = True,
         idle_timeout_secs: Optional[float] = 300,
@@ -205,8 +205,8 @@ class PipelineTask(BaseTask):
     ):
         super().__init__()
         self._pipeline = pipeline
-        self._clock = clock
-        self._params = params
+        self._clock = clock or SystemClock()
+        self._params = params or PipelineParams()
         self._check_dangling_tasks = check_dangling_tasks
         self._idle_timeout_secs = idle_timeout_secs
         self._idle_timeout_frames = idle_timeout_frames
@@ -224,6 +224,7 @@ class PipelineTask(BaseTask):
                     DeprecationWarning,
                 )
             observers = self._params.observers
+        observers = observers or []
         if self._enable_turn_tracking:
             self._turn_tracking_observer = TurnTrackingObserver()
             observers = [self._turn_tracking_observer] + list(observers)
diff --git a/src/pipecat/pipeline/task_observer.py b/src/pipecat/pipeline/task_observer.py
index 252708f8c..127ea3466 100644
--- a/src/pipecat/pipeline/task_observer.py
+++ b/src/pipecat/pipeline/task_observer.py
@@ -6,7 +6,7 @@
 
 import asyncio
 import inspect
-from typing import List
+from typing import List, Optional
 
 from attr import dataclass
 
@@ -39,8 +39,10 @@ class TaskObserver(BaseObserver):
 
     """
 
-    def __init__(self, *, observers: List[BaseObserver] = [], task_manager: BaseTaskManager):
-        self._observers = observers
+    def __init__(
+        self, *, observers: Optional[List[BaseObserver]] = None, task_manager: BaseTaskManager
+    ):
+        self._observers = observers or []
         self._task_manager = task_manager
         self._proxies: List[Proxy] = []
 
diff --git a/src/pipecat/processors/aggregators/llm_response.py b/src/pipecat/processors/aggregators/llm_response.py
index fa163ac0a..55ac0e2d5 100644
--- a/src/pipecat/processors/aggregators/llm_response.py
+++ b/src/pipecat/processors/aggregators/llm_response.py
@@ -7,7 +7,7 @@
 import asyncio
 from abc import abstractmethod
 from dataclasses import dataclass
-from typing import Dict, List, Literal, Set
+from typing import Dict, List, Literal, Optional, Set
 
 from loguru import logger
 
@@ -243,11 +243,11 @@ class LLMUserContextAggregator(LLMContextResponseAggregator):
         self,
         context: OpenAILLMContext,
         *,
-        params: LLMUserAggregatorParams = LLMUserAggregatorParams(),
+        params: Optional[LLMUserAggregatorParams] = None,
         **kwargs,
     ):
         super().__init__(context=context, role="user", **kwargs)
-        self._params = params
+        self._params = params or LLMUserAggregatorParams()
         if "aggregation_timeout" in kwargs:
             import warnings
 
@@ -446,11 +446,11 @@ class LLMAssistantContextAggregator(LLMContextResponseAggregator):
         self,
         context: OpenAILLMContext,
         *,
-        params: LLMAssistantAggregatorParams = LLMAssistantAggregatorParams(),
+        params: Optional[LLMAssistantAggregatorParams] = None,
         **kwargs,
     ):
         super().__init__(context=context, role="assistant", **kwargs)
-        self._params = params
+        self._params = params or LLMAssistantAggregatorParams()
 
         if "expect_stripped_words" in kwargs:
             import warnings
@@ -640,9 +640,9 @@ class LLMAssistantContextAggregator(LLMContextResponseAggregator):
 class LLMUserResponseAggregator(LLMUserContextAggregator):
     def __init__(
         self,
-        messages: List[dict] = [],
+        messages: Optional[List[dict]] = None,
         *,
-        params: LLMUserAggregatorParams = LLMUserAggregatorParams(),
+        params: Optional[LLMUserAggregatorParams] = None,
         **kwargs,
     ):
         super().__init__(context=OpenAILLMContext(messages), params=params, **kwargs)
@@ -662,9 +662,9 @@ class LLMUserResponseAggregator(LLMUserContextAggregator):
 class LLMAssistantResponseAggregator(LLMAssistantContextAggregator):
     def __init__(
         self,
-        messages: List[dict] = [],
+        messages: Optional[List[dict]] = None,
         *,
-        params: LLMAssistantAggregatorParams = LLMAssistantAggregatorParams(),
+        params: Optional[LLMAssistantAggregatorParams] = None,
         **kwargs,
     ):
         super().__init__(context=OpenAILLMContext(messages), params=params, **kwargs)
diff --git a/src/pipecat/processors/filters/wake_check_filter.py b/src/pipecat/processors/filters/wake_check_filter.py
index d15607e7c..d8661eae1 100644
--- a/src/pipecat/processors/filters/wake_check_filter.py
+++ b/src/pipecat/processors/filters/wake_check_filter.py
@@ -7,6 +7,7 @@
 import re
 import time
 from enum import Enum
+from typing import List
 
 from loguru import logger
 
@@ -31,7 +32,7 @@ class WakeCheckFilter(FrameProcessor):
             self.wake_timer = 0.0
             self.accumulator = ""
 
-    def __init__(self, wake_phrases: list[str], keepalive_timeout: float = 3):
+    def __init__(self, wake_phrases: List[str], keepalive_timeout: float = 3):
         super().__init__()
         self._participant_states = {}
         self._keepalive_timeout = keepalive_timeout
diff --git a/src/pipecat/processors/filters/wake_notifier_filter.py b/src/pipecat/processors/filters/wake_notifier_filter.py
index e2684d8e4..c7e6ed27a 100644
--- a/src/pipecat/processors/filters/wake_notifier_filter.py
+++ b/src/pipecat/processors/filters/wake_notifier_filter.py
@@ -22,7 +22,7 @@ class WakeNotifierFilter(FrameProcessor):
         self,
         notifier: BaseNotifier,
         *,
-        types: Tuple[Type[Frame]],
+        types: Tuple[Type[Frame], ...],
         filter: Callable[[Frame], Awaitable[bool]],
         **kwargs,
     ):
diff --git a/src/pipecat/processors/frameworks/rtvi.py b/src/pipecat/processors/frameworks/rtvi.py
index c2f7004ba..f759102ae 100644
--- a/src/pipecat/processors/frameworks/rtvi.py
+++ b/src/pipecat/processors/frameworks/rtvi.py
@@ -437,10 +437,10 @@ class RTVIObserver(BaseObserver):
         params (RTVIObserverParams): Settings to enable/disable specific messages.
     """
 
-    def __init__(self, rtvi: "RTVIProcessor", *, params: RTVIObserverParams = RTVIObserverParams()):
+    def __init__(self, rtvi: "RTVIProcessor", *, params: Optional[RTVIObserverParams] = None):
         super().__init__()
         self._rtvi = rtvi
-        self._params = params
+        self._params = params or RTVIObserverParams()
         self._bot_transcription = ""
         self._frames_seen = set()
         rtvi.set_errors_enabled(self._params.errors_enabled)
@@ -632,12 +632,12 @@ class RTVIProcessor(FrameProcessor):
     def __init__(
         self,
         *,
-        config: RTVIConfig = RTVIConfig(config=[]),
+        config: Optional[RTVIConfig] = None,
         transport: Optional[BaseTransport] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
-        self._config = config
+        self._config = config or RTVIConfig(config=[])
 
         self._bot_ready = False
         self._client_ready = False
diff --git a/src/pipecat/processors/gstreamer/pipeline_source.py b/src/pipecat/processors/gstreamer/pipeline_source.py
index 12b9cef67..84b8a050b 100644
--- a/src/pipecat/processors/gstreamer/pipeline_source.py
+++ b/src/pipecat/processors/gstreamer/pipeline_source.py
@@ -43,10 +43,10 @@ class GStreamerPipelineSource(FrameProcessor):
         audio_channels: int = 1
         clock_sync: bool = True
 
-    def __init__(self, *, pipeline: str, out_params: OutputParams = OutputParams(), **kwargs):
+    def __init__(self, *, pipeline: str, out_params: Optional[OutputParams] = None, **kwargs):
         super().__init__(**kwargs)
 
-        self._out_params = out_params
+        self._out_params = out_params or GStreamerPipelineSource.OutputParams()
         self._sample_rate = 0
 
         Gst.init()
diff --git a/src/pipecat/processors/idle_frame_processor.py b/src/pipecat/processors/idle_frame_processor.py
index ab98df771..36c7e9821 100644
--- a/src/pipecat/processors/idle_frame_processor.py
+++ b/src/pipecat/processors/idle_frame_processor.py
@@ -5,7 +5,7 @@
 #
 
 import asyncio
-from typing import Awaitable, Callable, List
+from typing import Awaitable, Callable, List, Optional
 
 from pipecat.frames.frames import Frame, StartFrame
 from pipecat.processors.frame_processor import FrameDirection, FrameProcessor
@@ -22,14 +22,14 @@ class IdleFrameProcessor(FrameProcessor):
         *,
         callback: Callable[["IdleFrameProcessor"], Awaitable[None]],
         timeout: float,
-        types: List[type] = [],
+        types: Optional[List[type]] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
 
         self._callback = callback
         self._timeout = timeout
-        self._types = types
+        self._types = types or []
         self._idle_task = None
 
     async def process_frame(self, frame: Frame, direction: FrameDirection):
diff --git a/src/pipecat/processors/logger.py b/src/pipecat/processors/logger.py
index 09a2d1674..b773df8c3 100644
--- a/src/pipecat/processors/logger.py
+++ b/src/pipecat/processors/logger.py
@@ -4,11 +4,17 @@
 # SPDX-License-Identifier: BSD 2-Clause License
 #
 
-from typing import Optional
+from typing import Optional, Tuple, Type
 
 from loguru import logger
 
-from pipecat.frames.frames import AudioRawFrame, BotSpeakingFrame, Frame, TransportMessageFrame
+from pipecat.frames.frames import (
+    BotSpeakingFrame,
+    Frame,
+    InputAudioRawFrame,
+    OutputAudioRawFrame,
+    TransportMessageFrame,
+)
 from pipecat.processors.frame_processor import FrameDirection, FrameProcessor
 
 logger = logger.opt(ansi=True)
@@ -19,16 +25,17 @@ class FrameLogger(FrameProcessor):
         self,
         prefix="Frame",
         color: Optional[str] = None,
-        ignored_frame_types: Optional[list] = [
+        ignored_frame_types: Tuple[Type[Frame], ...] = (
             BotSpeakingFrame,
-            AudioRawFrame,
+            InputAudioRawFrame,
+            OutputAudioRawFrame,
             TransportMessageFrame,
-        ],
+        ),
     ):
         super().__init__()
         self._prefix = prefix
         self._color = color
-        self._ignored_frame_types = tuple(ignored_frame_types) if ignored_frame_types else None
+        self._ignored_frame_types = ignored_frame_types
 
     async def process_frame(self, frame: Frame, direction: FrameDirection):
         await super().process_frame(frame, direction)
diff --git a/src/pipecat/serializers/telnyx.py b/src/pipecat/serializers/telnyx.py
index 61a89c7f0..6ef9f7c0d 100644
--- a/src/pipecat/serializers/telnyx.py
+++ b/src/pipecat/serializers/telnyx.py
@@ -79,7 +79,7 @@ class TelnyxFrameSerializer(FrameSerializer):
         inbound_encoding: str,
         call_control_id: Optional[str] = None,
         api_key: Optional[str] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
     ):
         """Initialize the TelnyxFrameSerializer.
 
@@ -92,11 +92,11 @@ class TelnyxFrameSerializer(FrameSerializer):
             params: Configuration parameters.
         """
         self._stream_id = stream_id
-        params.outbound_encoding = outbound_encoding
-        params.inbound_encoding = inbound_encoding
         self._call_control_id = call_control_id
         self._api_key = api_key
-        self._params = params
+        self._params = params or TelnyxFrameSerializer.InputParams()
+        self._params.outbound_encoding = outbound_encoding
+        self._params.inbound_encoding = inbound_encoding
 
         self._telnyx_sample_rate = self._params.telnyx_sample_rate
         self._sample_rate = 0  # Pipeline input rate
diff --git a/src/pipecat/serializers/twilio.py b/src/pipecat/serializers/twilio.py
index b169955ce..26a3fea5e 100644
--- a/src/pipecat/serializers/twilio.py
+++ b/src/pipecat/serializers/twilio.py
@@ -69,7 +69,7 @@ class TwilioFrameSerializer(FrameSerializer):
         call_sid: Optional[str] = None,
         account_sid: Optional[str] = None,
         auth_token: Optional[str] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
     ):
         """Initialize the TwilioFrameSerializer.
 
@@ -84,7 +84,7 @@ class TwilioFrameSerializer(FrameSerializer):
         self._call_sid = call_sid
         self._account_sid = account_sid
         self._auth_token = auth_token
-        self._params = params
+        self._params = params or TwilioFrameSerializer.InputParams()
 
         self._twilio_sample_rate = self._params.twilio_sample_rate
         self._sample_rate = 0  # Pipeline input rate
diff --git a/src/pipecat/services/anthropic/llm.py b/src/pipecat/services/anthropic/llm.py
index 43fe5ab6f..5e0ea0ad2 100644
--- a/src/pipecat/services/anthropic/llm.py
+++ b/src/pipecat/services/anthropic/llm.py
@@ -91,11 +91,12 @@ class AnthropicLLMService(LLMService):
         *,
         api_key: str,
         model: str = "claude-3-7-sonnet-20250219",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         client=None,
         **kwargs,
     ):
         super().__init__(**kwargs)
+        params = params or AnthropicLLMService.InputParams()
         self._client = client or AsyncAnthropic(
             api_key=api_key
         )  # if the client is provided, use it and remove it, otherwise create a new one
diff --git a/src/pipecat/services/assemblyai/stt.py b/src/pipecat/services/assemblyai/stt.py
index 2153d969e..41a27fd5b 100644
--- a/src/pipecat/services/assemblyai/stt.py
+++ b/src/pipecat/services/assemblyai/stt.py
@@ -38,12 +38,13 @@ class AssemblyAISTTService(STTService):
         *,
         api_key: str,
         sample_rate: Optional[int] = None,
-        encoding: AudioEncoding = AudioEncoding("pcm_s16le"),
+        encoding: Optional[AudioEncoding] = None,
         language=Language.EN,  # Only English is supported for Realtime
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        encoding = encoding or AudioEncoding("pcm_s16le")
         aai.settings.api_key = api_key
         self._transcriber: Optional[aai.RealtimeTranscriber] = None
 
diff --git a/src/pipecat/services/aws/llm.py b/src/pipecat/services/aws/llm.py
index f1a24bb18..9ec617678 100644
--- a/src/pipecat/services/aws/llm.py
+++ b/src/pipecat/services/aws/llm.py
@@ -530,17 +530,19 @@ class AWSBedrockLLMService(LLMService):
     def __init__(
         self,
         *,
+        model: str,
         aws_access_key: Optional[str] = None,
         aws_secret_key: Optional[str] = None,
         aws_session_token: Optional[str] = None,
         aws_region: str = "us-east-1",
-        model: str,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         client_config: Optional[Config] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
 
+        params = params or AWSBedrockLLMService.InputParams()
+
         # Initialize the AWS Bedrock client
         if not client_config:
             client_config = Config(
diff --git a/src/pipecat/services/aws/tts.py b/src/pipecat/services/aws/tts.py
index cba2acc5f..a0719f227 100644
--- a/src/pipecat/services/aws/tts.py
+++ b/src/pipecat/services/aws/tts.py
@@ -125,11 +125,13 @@ class AWSPollyTTSService(TTSService):
         region: Optional[str] = None,
         voice_id: str = "Joanna",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or AWSPollyTTSService.InputParams()
+
         self._polly_client = boto3.client(
             "polly",
             aws_access_key_id=aws_access_key_id,
diff --git a/src/pipecat/services/aws_nova_sonic/aws.py b/src/pipecat/services/aws_nova_sonic/aws.py
index 0e474fb89..2a342539e 100644
--- a/src/pipecat/services/aws_nova_sonic/aws.py
+++ b/src/pipecat/services/aws_nova_sonic/aws.py
@@ -142,7 +142,7 @@ class AWSNovaSonicLLMService(LLMService):
         region: str,
         model: str = "amazon.nova-sonic-v1:0",
         voice_id: str = "matthew",  # matthew, tiffany, amy
-        params: Params = Params(),
+        params: Optional[Params] = None,
         system_instruction: Optional[str] = None,
         tools: Optional[ToolsSchema] = None,
         send_transcription_frames: bool = True,
@@ -155,7 +155,7 @@ class AWSNovaSonicLLMService(LLMService):
         self._model = model
         self._client: Optional[BedrockRuntimeClient] = None
         self._voice_id = voice_id
-        self._params = params
+        self._params = params or Params()
         self._system_instruction = system_instruction
         self._tools = tools
         self._send_transcription_frames = send_transcription_frames
diff --git a/src/pipecat/services/azure/tts.py b/src/pipecat/services/azure/tts.py
index 9dde55496..e8be685a6 100644
--- a/src/pipecat/services/azure/tts.py
+++ b/src/pipecat/services/azure/tts.py
@@ -68,11 +68,13 @@ class AzureBaseTTSService(TTSService):
         region: str,
         voice="en-US-SaraNeural",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or AzureBaseTTSService.InputParams()
+
         self._settings = {
             "emphasis": params.emphasis,
             "language": self.language_to_service_language(params.language)
diff --git a/src/pipecat/services/cartesia/tts.py b/src/pipecat/services/cartesia/tts.py
index 5d37a583f..22493f229 100644
--- a/src/pipecat/services/cartesia/tts.py
+++ b/src/pipecat/services/cartesia/tts.py
@@ -11,7 +11,7 @@ import warnings
 from typing import AsyncGenerator, List, Optional, Union
 
 from loguru import logger
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 from pipecat.frames.frames import (
     CancelFrame,
@@ -90,7 +90,7 @@ class CartesiaTTSService(AudioContextWordTTSService):
         sample_rate: Optional[int] = None,
         encoding: str = "pcm_s16le",
         container: str = "raw",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         text_aggregator: Optional[BaseTextAggregator] = None,
         **kwargs,
     ):
@@ -113,6 +113,8 @@ class CartesiaTTSService(AudioContextWordTTSService):
             **kwargs,
         )
 
+        params = params or CartesiaTTSService.InputParams()
+
         self._api_key = api_key
         self._cartesia_version = cartesia_version
         self._url = url
@@ -317,7 +319,7 @@ class CartesiaHttpTTSService(TTSService):
     class InputParams(BaseModel):
         language: Optional[Language] = Language.EN
         speed: Optional[Union[str, float]] = ""
-        emotion: Optional[List[str]] = []
+        emotion: Optional[List[str]] = Field(default_factory=list)
 
     def __init__(
         self,
@@ -330,11 +332,13 @@ class CartesiaHttpTTSService(TTSService):
         sample_rate: Optional[int] = None,
         encoding: str = "pcm_s16le",
         container: str = "raw",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or CartesiaHttpTTSService.InputParams()
+
         self._api_key = api_key
         self._base_url = base_url
         self._cartesia_version = cartesia_version
diff --git a/src/pipecat/services/elevenlabs/tts.py b/src/pipecat/services/elevenlabs/tts.py
index 5e5a97e75..4b48a3d3d 100644
--- a/src/pipecat/services/elevenlabs/tts.py
+++ b/src/pipecat/services/elevenlabs/tts.py
@@ -184,7 +184,7 @@ class ElevenLabsTTSService(AudioContextWordTTSService):
         model: str = "eleven_flash_v2_5",
         url: str = "wss://api.elevenlabs.io",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         # Aggregating sentences still gives cleaner-sounding results and fewer
@@ -210,6 +210,8 @@ class ElevenLabsTTSService(AudioContextWordTTSService):
             **kwargs,
         )
 
+        params = params or ElevenLabsTTSService.InputParams()
+
         self._api_key = api_key
         self._url = url
         self._settings = {
@@ -512,7 +514,7 @@ class ElevenLabsHttpTTSService(WordTTSService):
         model: str = "eleven_flash_v2_5",
         base_url: str = "https://api.elevenlabs.io",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(
@@ -523,6 +525,8 @@ class ElevenLabsHttpTTSService(WordTTSService):
             **kwargs,
         )
 
+        params = params or ElevenLabsHttpTTSService.InputParams()
+
         self._api_key = api_key
         self._base_url = base_url
         self._params = params
diff --git a/src/pipecat/services/fal/stt.py b/src/pipecat/services/fal/stt.py
index 950d74d06..a019694fd 100644
--- a/src/pipecat/services/fal/stt.py
+++ b/src/pipecat/services/fal/stt.py
@@ -173,7 +173,7 @@ class FalSTTService(SegmentedSTTService):
         *,
         api_key: Optional[str] = None,
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(
@@ -181,6 +181,8 @@ class FalSTTService(SegmentedSTTService):
             **kwargs,
         )
 
+        params = params or FalSTTService.InputParams()
+
         if api_key:
             os.environ["FAL_KEY"] = api_key
         elif "FAL_KEY" not in os.environ:
diff --git a/src/pipecat/services/fish/tts.py b/src/pipecat/services/fish/tts.py
index 39c85281a..84e285aee 100644
--- a/src/pipecat/services/fish/tts.py
+++ b/src/pipecat/services/fish/tts.py
@@ -52,7 +52,7 @@ class FishAudioTTSService(InterruptibleTTSService):
         model: str,  # This is the reference_id
         output_format: FishAudioOutputFormat = "pcm",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(
@@ -62,6 +62,8 @@ class FishAudioTTSService(InterruptibleTTSService):
             **kwargs,
         )
 
+        params = params or FishAudioTTSService.InputParams()
+
         self._api_key = api_key
         self._base_url = "wss://api.fish.audio/v1/tts/live"
         self._websocket = None
diff --git a/src/pipecat/services/gemini_multimodal_live/gemini.py b/src/pipecat/services/gemini_multimodal_live/gemini.py
index b2614504b..10b284890 100644
--- a/src/pipecat/services/gemini_multimodal_live/gemini.py
+++ b/src/pipecat/services/gemini_multimodal_live/gemini.py
@@ -341,11 +341,14 @@ class GeminiMultimodalLiveLLMService(LLMService):
         start_video_paused: bool = False,
         system_instruction: Optional[str] = None,
         tools: Optional[Union[List[dict], ToolsSchema]] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         inference_on_context_initialization: bool = True,
         **kwargs,
     ):
         super().__init__(base_url=base_url, **kwargs)
+
+        params = params or InputParams()
+
         self._last_sent_time = 0
         self._api_key = api_key
         self._base_url = base_url
diff --git a/src/pipecat/services/gladia/stt.py b/src/pipecat/services/gladia/stt.py
index 8208d01e2..33c927158 100644
--- a/src/pipecat/services/gladia/stt.py
+++ b/src/pipecat/services/gladia/stt.py
@@ -194,7 +194,7 @@ class GladiaSTTService(STTService):
         confidence: float = 0.5,
         sample_rate: Optional[int] = None,
         model: str = "solaria-1",
-        params: GladiaInputParams = GladiaInputParams(),
+        params: Optional[GladiaInputParams] = None,
         **kwargs,
     ):
         """Initialize the Gladia STT service.
@@ -211,6 +211,8 @@ class GladiaSTTService(STTService):
         """
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or GladiaInputParams()
+
         # Warn about deprecated language parameter if it's used
         if params.language is not None:
             warnings.warn(
diff --git a/src/pipecat/services/google/image.py b/src/pipecat/services/google/image.py
index 5a73168dc..dc0218b8c 100644
--- a/src/pipecat/services/google/image.py
+++ b/src/pipecat/services/google/image.py
@@ -10,7 +10,7 @@ import os
 # Suppress gRPC fork warnings
 os.environ["GRPC_ENABLE_FORK_SUPPORT"] = "false"
 
-from typing import AsyncGenerator
+from typing import AsyncGenerator, Optional
 
 from loguru import logger
 from PIL import Image
@@ -32,19 +32,19 @@ class GoogleImageGenService(ImageGenService):
     class InputParams(BaseModel):
         number_of_images: int = Field(default=1, ge=1, le=8)
         model: str = Field(default="imagen-3.0-generate-002")
-        negative_prompt: str = Field(default=None)
+        negative_prompt: Optional[str] = Field(default=None)
 
     def __init__(
         self,
         *,
-        params: InputParams = InputParams(),
         api_key: str,
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
-        self.set_model_name(params.model)
-        self._params = params
+        self._params = params or GoogleImageGenService.InputParams()
         self._client = genai.Client(api_key=api_key)
+        self.set_model_name(self._params.model)
 
     def can_generate_metrics(self) -> bool:
         return True
diff --git a/src/pipecat/services/google/llm.py b/src/pipecat/services/google/llm.py
index e5fcf56db..d13dd546d 100644
--- a/src/pipecat/services/google/llm.py
+++ b/src/pipecat/services/google/llm.py
@@ -467,13 +467,16 @@ class GoogleLLMService(LLMService):
         *,
         api_key: str,
         model: str = "gemini-2.0-flash",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         system_instruction: Optional[str] = None,
         tools: Optional[List[Dict[str, Any]]] = None,
         tool_config: Optional[Dict[str, Any]] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
+
+        params = params or GoogleLLMService.InputParams()
+
         self.set_model_name(model)
         self._api_key = api_key
         self._system_instruction = system_instruction
diff --git a/src/pipecat/services/google/llm_vertex.py b/src/pipecat/services/google/llm_vertex.py
index a2a485ccd..9b0ed6501 100644
--- a/src/pipecat/services/google/llm_vertex.py
+++ b/src/pipecat/services/google/llm_vertex.py
@@ -52,7 +52,7 @@ class GoogleVertexLLMService(OpenAILLMService):
         credentials: Optional[str] = None,
         credentials_path: Optional[str] = None,
         model: str = "google/gemini-2.0-flash-001",
-        params: InputParams = OpenAILLMService.InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         """Initializes the VertexLLMService.
@@ -64,6 +64,7 @@ class GoogleVertexLLMService(OpenAILLMService):
             params (InputParams): Vertex AI input parameters.
             **kwargs: Additional arguments for OpenAILLMService.
         """
+        params = params or OpenAILLMService.InputParams()
         base_url = self._get_base_url(params)
         self._api_key = self._get_api_token(credentials, credentials_path)
 
diff --git a/src/pipecat/services/google/stt.py b/src/pipecat/services/google/stt.py
index d7373aa71..49b8fba6f 100644
--- a/src/pipecat/services/google/stt.py
+++ b/src/pipecat/services/google/stt.py
@@ -412,7 +412,7 @@ class GoogleSTTService(STTService):
         credentials_path: Optional[str] = None,
         location: str = "global",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         """Initialize the Google STT service.
@@ -431,6 +431,8 @@ class GoogleSTTService(STTService):
         """
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or GoogleSTTService.InputParams()
+
         self._location = location
         self._stream = None
         self._config = None
diff --git a/src/pipecat/services/google/tts.py b/src/pipecat/services/google/tts.py
index 487aec7a6..9725aa1c3 100644
--- a/src/pipecat/services/google/tts.py
+++ b/src/pipecat/services/google/tts.py
@@ -219,11 +219,13 @@ class GoogleTTSService(TTSService):
         credentials_path: Optional[str] = None,
         voice_id: str = "en-US-Neural2-A",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or GoogleTTSService.InputParams()
+
         self._settings = {
             "pitch": params.pitch,
             "rate": params.rate,
diff --git a/src/pipecat/services/groq/tts.py b/src/pipecat/services/groq/tts.py
index 828edf72b..6f73b1629 100644
--- a/src/pipecat/services/groq/tts.py
+++ b/src/pipecat/services/groq/tts.py
@@ -34,7 +34,7 @@ class GroqTTSService(TTSService):
         *,
         api_key: str,
         output_format: str = "wav",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         model_name: str = "playai-tts",
         voice_id: str = "Celeste-PlayAI",
         sample_rate: Optional[int] = GROQ_SAMPLE_RATE,
@@ -42,12 +42,15 @@ class GroqTTSService(TTSService):
     ):
         if sample_rate != self.GROQ_SAMPLE_RATE:
             logger.warning(f"Groq TTS only supports {self.GROQ_SAMPLE_RATE}Hz sample rate. ")
+
         super().__init__(
             pause_frame_processing=True,
             sample_rate=sample_rate,
             **kwargs,
         )
 
+        params = params or GroqTTSService.InputParams()
+
         self._api_key = api_key
         self._model_name = model_name
         self._output_format = output_format
diff --git a/src/pipecat/services/mem0/memory.py b/src/pipecat/services/mem0/memory.py
index a5f076b6e..8c93d72c9 100644
--- a/src/pipecat/services/mem0/memory.py
+++ b/src/pipecat/services/mem0/memory.py
@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: BSD 2-Clause License
 #
 
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Optional
 
 from loguru import logger
 from pydantic import BaseModel, Field
@@ -49,16 +49,19 @@ class Mem0MemoryService(FrameProcessor):
     def __init__(
         self,
         *,
-        api_key: str = None,
-        local_config: Dict[str, Any] = {},
-        user_id: str = None,
-        agent_id: str = None,
-        run_id: str = None,
-        params: InputParams = InputParams(),
+        api_key: Optional[str] = None,
+        local_config: Optional[Dict[str, Any]] = None,
+        user_id: Optional[str] = None,
+        agent_id: Optional[str] = None,
+        run_id: Optional[str] = None,
+        params: Optional[InputParams] = None,
     ):
         # Important: Call the parent class __init__ first
         super().__init__()
 
+        local_config = local_config or {}
+        params = params or Mem0MemoryService.InputParams()
+
         if local_config:
             self.memory_client = Memory.from_config(local_config)
         else:
diff --git a/src/pipecat/services/minimax/tts.py b/src/pipecat/services/minimax/tts.py
index 8dcbab66a..932996751 100644
--- a/src/pipecat/services/minimax/tts.py
+++ b/src/pipecat/services/minimax/tts.py
@@ -114,11 +114,13 @@ class MiniMaxHttpTTSService(TTSService):
         voice_id: str = "Calm_Woman",
         aiohttp_session: aiohttp.ClientSession,
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or MiniMaxHttpTTSService.InputParams()
+
         self._api_key = api_key
         self._group_id = group_id
         self._base_url = f"https://api.minimaxi.chat/v1/t2a_v2?GroupId={group_id}"
diff --git a/src/pipecat/services/neuphonic/tts.py b/src/pipecat/services/neuphonic/tts.py
index de12c8231..bfceca50b 100644
--- a/src/pipecat/services/neuphonic/tts.py
+++ b/src/pipecat/services/neuphonic/tts.py
@@ -80,7 +80,7 @@ class NeuphonicTTSService(InterruptibleTTSService):
         url: str = "wss://api.neuphonic.com",
         sample_rate: Optional[int] = 22050,
         encoding: str = "pcm_linear",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(
@@ -92,6 +92,8 @@ class NeuphonicTTSService(InterruptibleTTSService):
             **kwargs,
         )
 
+        params = params or NeuphonicTTSService.InputParams()
+
         self._api_key = api_key
         self._url = url
         self._settings = {
@@ -293,11 +295,13 @@ class NeuphonicHttpTTSService(TTSService):
         url: str = "https://api.neuphonic.com",
         sample_rate: Optional[int] = 22050,
         encoding: str = "pcm_linear",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or NeuphonicHttpTTSService.InputParams()
+
         self._api_key = api_key
         self._url = url
         self._settings = {
diff --git a/src/pipecat/services/openai/base_llm.py b/src/pipecat/services/openai/base_llm.py
index 641c96f5e..e90f87f3c 100644
--- a/src/pipecat/services/openai/base_llm.py
+++ b/src/pipecat/services/openai/base_llm.py
@@ -77,11 +77,14 @@ class BaseOpenAILLMService(LLMService):
         base_url=None,
         organization=None,
         project=None,
-        default_headers: Mapping[str, str] | None = None,
-        params: InputParams = InputParams(),
+        default_headers: Optional[Mapping[str, str]] = None,
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
+
+        params = params or BaseOpenAILLMService.InputParams()
+
         self._settings = {
             "frequency_penalty": params.frequency_penalty,
             "presence_penalty": params.presence_penalty,
diff --git a/src/pipecat/services/openai/llm.py b/src/pipecat/services/openai/llm.py
index 07b564fe1..44e0a40ce 100644
--- a/src/pipecat/services/openai/llm.py
+++ b/src/pipecat/services/openai/llm.py
@@ -6,7 +6,7 @@
 
 import json
 from dataclasses import dataclass
-from typing import Any
+from typing import Any, Optional
 
 from pipecat.frames.frames import (
     FunctionCallCancelFrame,
@@ -41,7 +41,7 @@ class OpenAILLMService(BaseOpenAILLMService):
         self,
         *,
         model: str = "gpt-4.1",
-        params: BaseOpenAILLMService.InputParams = BaseOpenAILLMService.InputParams(),
+        params: Optional[BaseOpenAILLMService.InputParams] = None,
         **kwargs,
     ):
         super().__init__(model=model, params=params, **kwargs)
diff --git a/src/pipecat/services/openai_realtime_beta/openai.py b/src/pipecat/services/openai_realtime_beta/openai.py
index 0c37f73ce..e705a9b18 100644
--- a/src/pipecat/services/openai_realtime_beta/openai.py
+++ b/src/pipecat/services/openai_realtime_beta/openai.py
@@ -8,6 +8,7 @@ import base64
 import json
 import time
 from dataclasses import dataclass
+from typing import Optional
 
 from loguru import logger
 
@@ -89,17 +90,20 @@ class OpenAIRealtimeBetaLLMService(LLMService):
         api_key: str,
         model: str = "gpt-4o-realtime-preview-2024-12-17",
         base_url: str = "wss://api.openai.com/v1/realtime",
-        session_properties: events.SessionProperties = events.SessionProperties(),
+        session_properties: Optional[events.SessionProperties] = None,
         start_audio_paused: bool = False,
         send_transcription_frames: bool = True,
         **kwargs,
     ):
         full_url = f"{base_url}?model={model}"
         super().__init__(base_url=full_url, **kwargs)
+
         self.api_key = api_key
         self.base_url = full_url
 
-        self._session_properties: events.SessionProperties = session_properties
+        self._session_properties: events.SessionProperties = (
+            session_properties or events.SessionProperties()
+        )
         self._audio_input_paused = start_audio_paused
         self._send_transcription_frames = send_transcription_frames
         self._websocket = None
diff --git a/src/pipecat/services/playht/tts.py b/src/pipecat/services/playht/tts.py
index 865b267c9..34fc6c81a 100644
--- a/src/pipecat/services/playht/tts.py
+++ b/src/pipecat/services/playht/tts.py
@@ -110,7 +110,7 @@ class PlayHTTTSService(InterruptibleTTSService):
         voice_engine: str = "Play3.0-mini",
         sample_rate: Optional[int] = None,
         output_format: str = "wav",
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(
@@ -119,6 +119,8 @@ class PlayHTTTSService(InterruptibleTTSService):
             **kwargs,
         )
 
+        params = params or PlayHTTTSService.InputParams()
+
         self._api_key = api_key
         self._user_id = user_id
         self._websocket_url = None
@@ -328,11 +330,13 @@ class PlayHTHttpTTSService(TTSService):
         voice_engine: str = "Play3.0-mini",
         protocol: str = "http",  # Options: http, ws
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or PlayHTHttpTTSService.InputParams()
+
         self._user_id = user_id
         self._api_key = api_key
 
diff --git a/src/pipecat/services/rime/tts.py b/src/pipecat/services/rime/tts.py
index 09a633456..b3f46961f 100644
--- a/src/pipecat/services/rime/tts.py
+++ b/src/pipecat/services/rime/tts.py
@@ -80,7 +80,7 @@ class RimeTTSService(AudioContextWordTTSService):
         url: str = "wss://users.rime.ai/ws2",
         model: str = "mistv2",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         text_aggregator: Optional[BaseTextAggregator] = None,
         **kwargs,
     ):
@@ -105,6 +105,8 @@ class RimeTTSService(AudioContextWordTTSService):
             **kwargs,
         )
 
+        params = params or RimeTTSService.InputParams()
+
         # Store service configuration
         self._api_key = api_key
         self._url = url
@@ -364,11 +366,13 @@ class RimeHttpTTSService(TTSService):
         aiohttp_session: aiohttp.ClientSession,
         model: str = "mistv2",
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or RimeHttpTTSService.InputParams()
+
         self._api_key = api_key
         self._session = aiohttp_session
         self._base_url = "https://users.rime.ai/v1/rime-tts"
diff --git a/src/pipecat/services/riva/stt.py b/src/pipecat/services/riva/stt.py
index b70d63e4e..92a3463c3 100644
--- a/src/pipecat/services/riva/stt.py
+++ b/src/pipecat/services/riva/stt.py
@@ -99,10 +99,13 @@ class RivaSTTService(STTService):
             "model_name": "parakeet-ctc-1.1b-asr",
         },
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
+
+        params = params or RivaSTTService.InputParams()
+
         self._api_key = api_key
         self._profanity_filter = False
         self._automatic_punctuation = True
@@ -322,11 +325,13 @@ class RivaSegmentedSTTService(SegmentedSTTService):
             "model_name": "canary-1b-asr",
         },
         sample_rate: Optional[int] = None,
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
 
+        params = params or RivaSegmentedSTTService.InputParams()
+
         # Set model name
         self.set_model_name(model_function_map.get("model_name"))
 
@@ -533,7 +538,7 @@ class ParakeetSTTService(RivaSTTService):
             "model_name": "parakeet-ctc-1.1b-asr",
         },
         sample_rate: Optional[int] = None,
-        params: RivaSTTService.InputParams = RivaSTTService.InputParams(),  # Use parent class's type
+        params: Optional[RivaSTTService.InputParams] = None,  # Use parent class's type
         **kwargs,
     ):
         super().__init__(
diff --git a/src/pipecat/services/riva/tts.py b/src/pipecat/services/riva/tts.py
index a61155685..31850ea17 100644
--- a/src/pipecat/services/riva/tts.py
+++ b/src/pipecat/services/riva/tts.py
@@ -44,7 +44,7 @@ class RivaTTSService(TTSService):
     def __init__(
         self,
         *,
-        api_key: str = None,
+        api_key: str,
         server: str = "grpc.nvcf.nvidia.com:443",
         voice_id: str = "Magpie-Multilingual.EN-US.Ray",
         sample_rate: Optional[int] = None,
@@ -52,10 +52,13 @@ class RivaTTSService(TTSService):
             "function_id": "877104f7-e885-42b9-8de8-f6e4c6303969",
             "model_name": "magpie-tts-multilingual",
         },
-        params: InputParams = InputParams(),
+        params: Optional[InputParams] = None,
         **kwargs,
     ):
         super().__init__(sample_rate=sample_rate, **kwargs)
+
+        params = params or RivaTTSService.InputParams()
+
         self._api_key = api_key
         self._voice_id = voice_id
         self._language_code = params.language
@@ -136,14 +139,10 @@ class RivaTTSService(TTSService):
 
 
 class FastPitchTTSService(RivaTTSService):
-    class InputParams(BaseModel):
-        language: Optional[Language] = Language.EN_US
-        quality: Optional[int] = 20
-
     def __init__(
         self,
         *,
-        api_key: str = None,
+        api_key: str,
         server: str = "grpc.nvcf.nvidia.com:443",
         voice_id: str = "English-US.Female-1",
         sample_rate: Optional[int] = None,
@@ -151,11 +150,12 @@ class FastPitchTTSService(RivaTTSService):
             "function_id": "0149dedb-2be8-4195-b9a0-e57e0e14f972",
             "model_name": "fastpitch-hifigan-tts",
         },
-        params: InputParams = InputParams(),
+        params: Optional[RivaTTSService.InputParams] = None,
         **kwargs,
     ):
         super().__init__(
             api_key=api_key,
+            server=server,
             voice_id=voice_id,
             sample_rate=sample_rate,
             model_function_map=model_function_map,
diff --git a/src/pipecat/services/tts_service.py b/src/pipecat/services/tts_service.py
index ed37caa01..cb0e2ea45 100644
--- a/src/pipecat/services/tts_service.py
+++ b/src/pipecat/services/tts_service.py
@@ -64,7 +64,7 @@ class TTSService(AIService):
         # Text aggregator to aggregate incoming tokens and decide when to push to the TTS.
         text_aggregator: Optional[BaseTextAggregator] = None,
         # Text filter executed after text has been aggregated.
-        text_filters: Sequence[BaseTextFilter] = [],
+        text_filters: Optional[Sequence[BaseTextFilter]] = None,
         text_filter: Optional[BaseTextFilter] = None,
         # Audio transport destination of the generated frames.
         transport_destination: Optional[str] = None,
@@ -83,7 +83,7 @@ class TTSService(AIService):
         self._voice_id: str = ""
         self._settings: Dict[str, Any] = {}
         self._text_aggregator: BaseTextAggregator = text_aggregator or SimpleTextAggregator()
-        self._text_filters: Sequence[BaseTextFilter] = text_filters
+        self._text_filters: Sequence[BaseTextFilter] = text_filters or []
         self._transport_destination: Optional[str] = transport_destination
 
         if text_filter:
diff --git a/src/pipecat/tests/utils.py b/src/pipecat/tests/utils.py
index 3f5182044..afa5a9949 100644
--- a/src/pipecat/tests/utils.py
+++ b/src/pipecat/tests/utils.py
@@ -79,10 +79,13 @@ async def run_test(
     expected_down_frames: Optional[Sequence[type]] = None,
     expected_up_frames: Optional[Sequence[type]] = None,
     ignore_start: bool = True,
-    observers: List[BaseObserver] = [],
-    start_metadata: Dict[str, Any] = {},
+    observers: Optional[List[BaseObserver]] = None,
+    start_metadata: Optional[Dict[str, Any]] = None,
     send_end_frame: bool = True,
 ) -> Tuple[Sequence[Frame], Sequence[Frame]]:
+    observers = observers or []
+    start_metadata = start_metadata or {}
+
     received_up = asyncio.Queue()
     received_down = asyncio.Queue()
     source = QueuedFrameProcessor(
diff --git a/src/pipecat/transports/network/websocket_client.py b/src/pipecat/transports/network/websocket_client.py
index 535a0ab21..693be54c9 100644
--- a/src/pipecat/transports/network/websocket_client.py
+++ b/src/pipecat/transports/network/websocket_client.py
@@ -250,11 +250,11 @@ class WebsocketClientTransport(BaseTransport):
     def __init__(
         self,
         uri: str,
-        params: WebsocketClientParams = WebsocketClientParams(),
+        params: Optional[WebsocketClientParams] = None,
     ):
         super().__init__()
 
-        self._params = params
+        self._params = params or WebsocketClientParams()
 
         callbacks = WebsocketClientCallbacks(
             on_connected=self._on_connected,
@@ -262,7 +262,7 @@ class WebsocketClientTransport(BaseTransport):
             on_message=self._on_message,
         )
 
-        self._session = WebsocketClientSession(uri, params, callbacks, self.name)
+        self._session = WebsocketClientSession(uri, self._params, callbacks, self.name)
         self._input: Optional[WebsocketClientInputTransport] = None
         self._output: Optional[WebsocketClientOutputTransport] = None
 
diff --git a/src/pipecat/transports/services/daily.py b/src/pipecat/transports/services/daily.py
index b31396433..095084037 100644
--- a/src/pipecat/transports/services/daily.py
+++ b/src/pipecat/transports/services/daily.py
@@ -95,7 +95,7 @@ class WebRTCVADAnalyzer(VADAnalyzer):
         params: VAD configuration parameters (VADParams).
     """
 
-    def __init__(self, *, sample_rate: Optional[int] = None, params: VADParams = VADParams()):
+    def __init__(self, *, sample_rate: Optional[int] = None, params: Optional[VADParams] = None):
         super().__init__(sample_rate=sample_rate, params=params)
 
         self._webrtc_vad = Daily.create_native_vad(
@@ -1223,7 +1223,7 @@ class DailyTransport(BaseTransport):
         room_url: str,
         token: Optional[str],
         bot_name: str,
-        params: DailyParams = DailyParams(),
+        params: Optional[DailyParams] = None,
         input_name: Optional[str] = None,
         output_name: Optional[str] = None,
     ):
@@ -1256,9 +1256,11 @@ class DailyTransport(BaseTransport):
             on_recording_stopped=self._on_recording_stopped,
             on_recording_error=self._on_recording_error,
         )
-        self._params = params
+        self._params = params or DailyParams()
 
-        self._client = DailyTransportClient(room_url, token, bot_name, params, callbacks, self.name)
+        self._client = DailyTransportClient(
+            room_url, token, bot_name, self._params, callbacks, self.name
+        )
         self._input: Optional[DailyInputTransport] = None
         self._output: Optional[DailyOutputTransport] = None
 
diff --git a/src/pipecat/transports/services/livekit.py b/src/pipecat/transports/services/livekit.py
index 4f215d04f..53a9b1789 100644
--- a/src/pipecat/transports/services/livekit.py
+++ b/src/pipecat/transports/services/livekit.py
@@ -499,7 +499,7 @@ class LiveKitTransport(BaseTransport):
         url: str,
         token: str,
         room_name: str,
-        params: LiveKitParams = LiveKitParams(),
+        params: Optional[LiveKitParams] = None,
         input_name: Optional[str] = None,
         output_name: Optional[str] = None,
     ):
@@ -515,7 +515,7 @@ class LiveKitTransport(BaseTransport):
             on_data_received=self._on_data_received,
             on_first_participant_joined=self._on_first_participant_joined,
         )
-        self._params = params
+        self._params = params or LiveKitParams()
 
         self._client = LiveKitTransportClient(
             url, token, room_name, self._params, callbacks, self.name
diff --git a/src/pipecat/utils/text/markdown_text_filter.py b/src/pipecat/utils/text/markdown_text_filter.py
index 3bac0cb95..c5ace159e 100644
--- a/src/pipecat/utils/text/markdown_text_filter.py
+++ b/src/pipecat/utils/text/markdown_text_filter.py
@@ -26,9 +26,9 @@ class MarkdownTextFilter(BaseTextFilter):
         filter_code: Optional[bool] = False
         filter_tables: Optional[bool] = False
 
-    def __init__(self, params: InputParams = InputParams(), **kwargs):
+    def __init__(self, params: Optional[InputParams] = None, **kwargs):
         super().__init__(**kwargs)
-        self._settings = params
+        self._settings = params or MarkdownTextFilter.InputParams()
         self._in_code_block = False
         self._in_table = False
         self._interrupted = False