The next Step is on How to Remove the Volume Limit, also Called Reduce Loud Sound. Volume is maximum, but the sound is limited, Check you have applied the volume limit for iPhone music volume.
Here I remind you that keep your iPhone is connected with a bluetooth accessory and use the volume up button to increase bluetooth volume. Repair Bluetooth Call Volume Too low on iPhone & iPad Solution 1. How can I remove the bluetooth profile form my iOS device?.Solution 4: adjust Audio Level on left/right headphone.Turn off Volume Limit/Reduce Loud Sound – Set to maximum Repair Bluetooth Call Volume Too low on iPhone & iPad.
