It's all about signal to noise ratio. 50-55 db isn't that loud....unless it's quiet in your room and then yes, that noise level in a quiet room can be maddening. Also, your phone spl meter is probably A weighted, which isn't capturing a lot of the low frequency energy. So what you experience is likely even worse than what your phone spl meter is measuring. Thanks for letting us know and I"m sorry you're experiencing this. I've had to endure this before and it sucks.According to the SPL app on my phone it was over 50dB in our room with the door closed Sunday night after midnight. It went on until ~4AM..