Bolse® 12W Portable Smart NFC Bluetooth v4.0 speakers (two large 40mm driver 6W) with touch control function and up to 15 hours of play time for smartphones, tablets PC, laptop, Ultrabook, with Microphone (Wireless Phone Accessory)
Total unsuitable to quietly listen to music. May occur that this phenomenon at bluetooh devices, is aware. In this case, the hum can be heard very clearly and I noticed immediately. I have not tested the device.