When calibrating your subwoofer level, does it make a difference whether you adjust the level through the receiver or the gain level on the actual subwoofer? Is there a difference between the two?
Shouldn't make too much difference if any in theory.
A couple of years ago it was reported that turning up the sub output on some Yamaha receivers would cause distortion vs using a lower output setting on the reciever and higher setting on the sub's volume control.
Some subs that come on by sensing input from the reciever may not come on when the receiver's output is set too low.
The range of output level on recievers varies, what you might want to aim for is a balance between output level setting on the receiver and volume setting on the sub itself so that the desired bass is achieved with the receiver's output setting somewhere near the middle of it's range.