Reasons for poor sound quality with a Bluetooth headset connected to a Mac and how to fix it



When using a Bluetooth headset on a Mac, for some reason the sound quality may deteriorate significantly or there may be popping noise mixed in. Daniel Gonzalez-Reina, who develops the audio settings app for Mac ``

Recadio '', explains why the sound quality deteriorates when connecting a Bluetooth headset to a Mac.

Why Is Bluetooth Sound Quality Bad on My Mac
https://www.recadio.com/blog/why-is-bluetooth-sound-quality-bad-on-my-mac

Apple has mentioned the possibility of poor sound quality when using Bluetooth headsets, and has prepared the following page.

If you experience poor sound quality when using Bluetooth headphones on your Mac - Apple Support (Japan)
https://support.apple.com/ja-jp/102217

In this article, Apple explains why the sound quality and volume decrease when using a Bluetooth headset.

This phenomenon occurs because Bluetooth has two modes.
・One mode is for listening to high-quality audio,
・The other mode is for both listening and speaking using the microphone. When Bluetooth switches to the second mode, the audio quality will be reduced until the microphone is no longer used.




Here, Mr. Reina explained the concept of Bluetooth profile. Bluetooth profiles are like rules used to connect Bluetooth, and there are various types. The two types that are important here are Advanced Audio Distribution Profile (A2DP) for streaming music and Hands Free Profile (HFP) for answering calls hands-free.

Apple's ``mode for listening to high-quality audio'' is A2DP, and ``mode for both listening and speaking with a microphone'' is HFP. A2DP only allows audio streaming from one device to another in one direction, whereas HFP allows for both directions since it is conversation-based. When you connect to a Bluetooth headset on your Mac, it will connect using HFP instead of A2DP.



However, unlike A2DP, which prioritizes sound quality, the audio codec used in HFP emphasizes low latency over sound quality. At the time of writing this article, there are codecs with better sound quality, but Apple uses the SBC codec for HFP. Therefore, when listening to audio with a Bluetooth headset connected to a Mac, noise may be mixed in and the sound quality may deteriorate.

In other words, when connecting a Bluetooth headset to a Mac, you only need to set it to connect using A2DP instead of HFP, and to do so, you can disable the Mac from using the Bluetooth headset's microphone. However, there is no way to disable the microphone on a Mac, so you should either manually modify the audio settings each time, or use an audio settings app like Recadio, Reyna says.

in Hardware, Posted by log1i_yk