A:AnswerThe CHARGE 3 is compatible with Android and iOS devices. The CHARGE 3 can be connected to a source device in two ways; via Bluetooth or Auxiliary/Wired connection. The CHARGE 3 has an AUX port which is located right beside the charging port of the speaker. You can plug your Samsung phone to the CHARGE3 3’s aux port using a 3.5mm audio cable to play music.
A:AnswerMmmmm
There is a delay on BT sound processing, also if your device is an iphone or android phone is probable that you cannot strean audio via BT and send audio via earphone jack at the same time.
A:AnswerNo, not on the speaker itself. However, I'm not sure if you play music through your iPhone, whether you can adjust the sound through third party apps.