I stayed for six nights during a solo week in Lisbon. The room and the flat was just what I needed as a solo traveler and in a great location to access the city. (I walked everywhere I went within the main part of the city Estrella to Alfama.) The neighborhood is busy, definitely more so on weekend nights, but as others have mentioned the inner set of doors for the balcony make a huge difference and block nearly all the sound. Thoroughly entertained by the door guy at one of the bars downstairs that greeted me as “oh you’re the neighbor” by my last night. Ciao, Lisbon, I’ll miss you!