Bass frequencies aren't attenuated in passing through materials as much as higher guitar frequencies, hence they'll travel farther and be more likely to resonate with panels and box framing structures used in many apartment buildings. A lady that lives above me in my apartment complex told me that she could always tell when I played because one of the windows in her kitchen would buzz whenever I played, despite my amp being at very low volume. When she's not home I'm fine using my amp during the daytime and a reasonably low volume, anything louder causes stuff in my apartment to start buzzing and rattling. After 8pm, or whenever she's there, I plug my headphones into my headphone amp and plug into my DI if I want to shape my tone. I always carry my Vox Amplug2 portable headphone amp in my gig bag for any other time, like in coffee shops, when I don't want to disturb people around me.