The recent Android Oreo update for Oneplus 5 and Oneplus5T mobile phones have disabled inbuilt Audio Tuner for Bluetooth headphones, Bluetooth earphones & Bluetooth external speakers.
To overcome this problem Oneplus 5 and Oneplus5T mobile users can use Snapdragon's Music player and MusicFX (Audio+) application. The MusicFX can be used as a replacement for Audio Tuner which supports Bluetooth and most of the system wide applications.
Please note that it is not required to ROOT your mobile phone or have Magisk for system wide to use MusicFX (Audio+). So Snapdragon's Music player and MusicFX APK will get installed on non rooted device without any issues
Snapdragon MusicFX (Audio+):
Click here to download the Snapdragon MusicFX (Audio+) version 1.4 APK
Snapdragon MusicFX Screenshot:
Click here to download Snapdragon Music version 8.0 APK.
Snapdragon Music Screenshot:
Most of the music players including Google Play Music supports MusicFX as audio tuner.
The Snapdragon's Music player and MusicFX (Audio+) android application also works on most of the mobiles having Snapdragon processor. You may try installing and report to us in the comment section.