I have an Antminer S7LN running 24/7, i would assume the noise-output is roughly the same or even abit more on the S9. I placed one unit in the booth in my apartment which is pretty well isolated but with limited airflow. These machines generate ALOT of heat and noise, so a room with good airflow and fairly isloated is near enough a must.
If you live in a newer apartment block i wouldnt worry too much about noise the neighbours, as for the older ones where you can hear your neighbour cough up a lung 3 floors up.
Despite all the noise and heat, this is still a nice and fun way of making money. Theres no guarantees with the BTC price. It could plummet, but i could also skyrocket.
Happy mining
