This is possibly a niche review, but for those of us with hearing loss, it could be a game-changer.   The Mackie OnyxGO is a rechargeable, battery-powered microphone, mixer, EQ and 3.5mm monitor output socket, in a box slightly smaller that a 9v battery.   It is designed for podcasting, and the audio signal is fed to your phone by Bluetooth, so you can then record it using the companion App. The signal is also fed to the headphone socket on the device. Within the app there is