I've always felt constrained by relying on the Tesla sound system equalizer when playing music directly from my USB drive. I've occasionally connected my old Sony Walkman MP3 player to my Tesla via hardwired USB instead, but the system then retrieves songs from the Walkman strictly as a memory device, i.e. the tone controls in the player are bypassed. I would really prefer to take advantage of the audio tailoring capability from something like a good headphone amplifier and then pipe that output to the Tesla sound system, in part to compensate for my hearing loss. As an experiment, I bought an Avantree Bluetooth transmitter from Amazon, which accepts analog audio from a 3.5mm stereo cable and connects to Bluetooth speakers or headphones, thinking that I might be able to interface an analog stereo source to the Tesla this way. I was only briefly able to establish Bluetooth pairing with the Tesla screen, but unfortunately couldn't maintain it or reconnect. Has anyone been able to successfully pair the Tesla to any brand of analog-to-Bluetooth transmitter? Alternatively, has anyone tried an all-digital MP3 in-to-USB out solution, with audio tailoring in between (using IoS devices or other hardware)? If this question has already been addressed, please let me know. Thanks in advance!