Switcher saves you from shitty sound when using a microphone with Bluetooth headphones macOS

The Problem

Bluetooth doesn't have enough bandwidth to support high-quality audio and microphone input simultaneously. When you connect your AirPods to your Mac, the system may switch to the HFP codec to enable the microphone. This codec is designed for phone calls and has a lower audio quality than the A2DP codec used for music playback.

Tom-Solid, describes the issue:

"The sound was tinny, lacked bass, and was marred by crackling sounds... It turns out that using the AirPods' microphone on a Mac may automatically switch to HFP, which results in poor audio quality even during playback."

How Switcher Helps

Switcher is a simple utility that automatically switches the sound input to a non-Bluetooth microphone upon connecting your AirPods to your Mac. This action prevents the Mac from using the HFP codec, ensuring that you always receive the best sound quality.

Manual Solution (doesn't persist)

To manually fix this issue, upon each connection of AirPods to your Mac, you can follow these steps:

• Navigate to Sound Settings on your Mac.
• Access the Output & Input section.
• Click on the Input tab.
• Select any input device other than your Apple AirPod's microphone.

Following these steps should immediately improve the sound quality.

Installation

Homebrew

brew tap Bobronium/tap
brew install switcher

The application is using ad-hock signature, so you need to allow it in the system settings. The window will open automatically during the installation.

It will automatically launch at login. To remove it from the login items, run:

osascript -e 'tell application "System Events" to delete login item "Switcher"'

or see manual installation instructions below.

Manual

1. Download the Application

   • Download the Switcher-vX.X.X.dmg from the latest release or build application from the source code.

2. Install the Application

   • Open Switcher-vX.X.X.dmg.
   • Drag Switcher.app to the Applications folder on your Mac.

3. Set to Launch at Login

   • If you want Switcher to launch automatically each time you log in to your Mac:
     • Open System Settings -> General -> Login Items
     • Click the + button and navigate to the Applications folder.
     • Select Switcher.app and click Add.

Credits

• Tom-Solid for the original solution.
• @elrumo for the App Icon
• Many other people who made this possible by providing their source code, questions and answers, which were used to my education and later were used to train LLMs that helped me to write Swift code.

Development

Create an icon:

curl https://parsefiles.back4app.com/JPaQcFfEEQ1ePBxbf6wvzkPMEqKYHhPYv8boI1Rc/f76537cc3a5709222e29fe1fa9d85595_1708726295537.icns -o original_icon.icns
uv run stylize_icons.py original_icon.icns switcher.icns --jpeg-quality 10 --pixelation-factor 16 --saturation-factor 0.24 --angle 109 --pixelated-line --offset 11
uv run stylize_icons.py switcher.icns switcher.icns      --jpeg-quality 8  --pixelation-factor 1  --saturation-factor 1    --angle 109 --pixelated-line --offset 11
uv run icns_to_appiconset.py switcher.icns Switcher/Assets.xcassets/AppIcon.appiconset