PEBL is a portable AI sound-masking system consisting of four slim wireless speaker discs and a stacking charge dock. Placed around a desk or bed, the discs pick up ambient noise through built-in microphones, classify the acoustic situation on the device, and generate masking sound in real time. The output combines engineered noise matched to the measured spectrum with natural textures such as rain and distant surf. The four units synchronize over a wireless mesh and adjust their output by direction, forming an even masking zone around the user rather than a single loud point. A companion app shows the live noise analysis and mix controls, and a microphone-free Speech-band preset covers conversation frequencies in privacy-sensitive rooms. All analysis runs on the device and no audio is stored or transmitted. The stack charges as one unit and carries in one hand.