Our upstairs neighbor has asked kindly that we implement a noise curfew.
As of now please refrain from using power tools/other loud tools after 12am. He didn’t say a time in the morning, but using my best judgment I will say the curfew will end at 8am.
Thanks,
Jon
I’m sorry for the noise, I get really stoned off his hookah sessions he decides to share for FREE with the hive that I forger how late it is sometimes lol
Hey all, afraid to say, Dave B is right. Air compressor does pose noise problem.
Air compressor should be isolated / decoupled from floor and moved a hair away from any shared walls with upstairs. 3+ft from walls is general rule of thumb.
Bass is a larger problem here than high frequency noise. 60Hz oscillation of the motor coupled to floor and walls in that space make it +9-12dB louder. The wavelength of 60Hz motor rumble is 5.67 meters, so this puts at least 4x more sound energy in neighbor’s appt than in our metal room! 120 Hz and 240 Hz harmonics likely cause standing wave phenomenon adding another 6 to 9 dB in structural supports.
Since wood studs and metal beams connect, there is mechanical coupling and air gap insulation provides absolutely no impedance to low frequency (almost 0 Sabines). In my world we build floating floors over tons of sand, 1" layer of rubber, and decouple walls by building two non-attached stud walls with 6-12" gap between. I’m not suggesting this…
Simple answer: machine rubber under compressor and auto turn off at midnight (which can always be overridden when we have permission from neighbor). This can also reduce noise in our space. Really we should consider this for mill as well. Happily, CNC does not pose this problem 
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There is a reason it’s called machine rubber…
Lorin
All,
You get extra credit if you put heavy-duty springs between the feet and the machine rubber.
A timer shouldn’t be too much of an expense…
James
You can’t just pull the power on the air compressor if it’s running. The pressure relief valve needs to operate to release pressure on the compressor head, or they’ll fail pretty quickly. Last time I checked, the compressor needs power to open the valve (i.e. it doesn’t just open when power is lost)