[Bug]: TX audio is too quiet with the default microphone volume

[awatchar]

Summary

The transmitted (TX) audio level is significantly too low when using the current default audio settings.

Under Mumla Settings → Audio → Microphone volume, the default value is currently 100%. At this level, receiving stations report that the transmitted voice is much quieter than expected and can be difficult to hear.

Manually increasing Microphone volume to 200% produces a more appropriate TX audio level for radio communication.

Steps to reproduce

1. Install or reset Minimum so that the default audio settings are used.
2. Connect to a Mumble server and select a channel.
3. Leave Settings → Audio → Microphone volume at the default value of 100%.
4. Transmit using PTT and monitor the audio from another station.
5. Observe that the received TX audio is significantly too quiet.
6. Change Microphone volume to 200%.
7. Transmit again and observe that the received audio is noticeably louder and more suitable for normal communication.

Current behavior

The default Microphone volume is 100%, resulting in a low TX audio level.

The current default is defined in two places:

app/src/main/res/xml/settings_audio.xml

android:defaultValue="100"

app/src/main/java/se/lublin/mumla/Settings.java

public static final Integer DEFAULT_AMPLITUDE_BOOST = 100;

The preference already supports a maximum value of 200%.

Expected behavior

The default TX audio level should be sufficiently loud and intelligible without requiring operators to change the audio settings manually.

The proposed change is to set the default Microphone volume to 200%.

Proposed XML change

android:defaultValue="200"

Proposed Java change

public static final Integer DEFAULT_AMPLITUDE_BOOST = 200;

Both values should be updated together so that the preference UI and the Settings class remain consistent.

Acceptance criteria

• A fresh installation defaults the Microphone volume to 200%.
• The Audio settings screen displays 200% as the default value.
• Settings.getAmplitudeBoostMultiplier() returns 2.0f when no user-selected value has been stored.
• Existing users who explicitly selected another Microphone volume retain their selected value.
• The new default improves TX audio intelligibility.
• Testing confirms that the new default does not cause unacceptable clipping or distortion.
• Background-noise amplification remains acceptable.

Test environment

• Device model: [T56 / T99 / Generic Android]
• Android version/API: [Enter version]
• Minimum version or commit: [Enter APK version or commit]
• Network: [Wi-Fi / Mobile network]
• Transmit mode: Push-to-talk
• Screen state: [On / Off]
• Receiving client/device: [Enter monitoring client or device]

Workaround

Open Mumla Settings → Audio → Microphone volume and manually change the value from 100% to 200%.