diff --git a/src/tuimble/config.py b/src/tuimble/config.py
index ee2c8d9..14af7c4 100644
--- a/src/tuimble/config.py
+++ b/src/tuimble/config.py
@@ -16,6 +16,8 @@ class ServerConfig:
     username: str = "tuimble-user"
     password: str = ""
     channel: str = ""
+    certfile: str = ""
+    keyfile: str = ""
 
 
 @dataclass
@@ -24,6 +26,8 @@ class AudioConfig:
     output_device: int | None = None
     sample_rate: int = 48000
     frame_size: int = 960  # 20ms at 48kHz
+    input_gain: float = 1.0
+    output_gain: float = 1.0
 
 
 @dataclass
diff --git a/tests/test_config.py b/tests/test_config.py
index 30b7ca5..b7a4896 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1,6 +1,6 @@
 """Tests for configuration module."""
 
-from tuimble.config import Config, PttConfig, ServerConfig
+from tuimble.config import AudioConfig, Config, PttConfig, ServerConfig
 
 
 def test_default_config():
@@ -21,3 +21,27 @@ def test_ptt_config_defaults():
     ptt = PttConfig()
     assert ptt.key == "f4"
     assert ptt.backend == "auto"
+
+
+def test_audio_gain_defaults():
+    acfg = AudioConfig()
+    assert acfg.input_gain == 1.0
+    assert acfg.output_gain == 1.0
+
+
+def test_audio_gain_custom():
+    acfg = AudioConfig(input_gain=0.5, output_gain=1.5)
+    assert acfg.input_gain == 0.5
+    assert acfg.output_gain == 1.5
+
+
+def test_server_cert_defaults():
+    srv = ServerConfig()
+    assert srv.certfile == ""
+    assert srv.keyfile == ""
+
+
+def test_server_cert_custom():
+    srv = ServerConfig(certfile="/path/cert.pem", keyfile="/path/key.pem")
+    assert srv.certfile == "/path/cert.pem"
+    assert srv.keyfile == "/path/key.pem"