try with another phone to check if your phone is not power limited on its usb. otherwise it may be related to "maximum output level is limited to about 1Vrms due to automatic impedance detection" that may only occur on android and not on windows ? ( from https://zhuanlan.zhihu.com/p/94991395 )So I thought the Meizu Pro dongle was supposed to output it's maximum power on an Android phone? It gets much louder plugged into the USB-C port on my windows laptop. Roughly 20% on the windows laptop is equal to roughly 50% on my Android phone.