1) As far as I know, YES!
Here are the corrections. At any of the given frequencies, the reading on your meter is off by these amounts.
For example: At 40Hz, if your meter reads 75dB, you’re actually hearing 77.5dB. To achieve an actual output of 75db, turn the volume down until the meter reads 72.5dB. You’ll then be hearing 75dB.
At 5kHz, if your meter reads 75dB, you’re actually hearing 73db. To achieve an actual output of 75dB, turn the volume up until the meter reads 77db, You’ll then be hearing 75dB
2) I've never used warble tones, so I can't be any help here.
3) I don't believe it matters. Just be sure the sub is getting a strong enough signal from the receiver to cause it to turn on. Start with your receivers output set at 0. If that level is turning your sub on adequately, use the volume knob on the sub to balance your sub with the rest of the system when you calibrate. Then, should you want to turn the sub up or down, just because it's easier, use the receiver's menu.
If sometimes you sub doesn't turn on properly with the receiver's menu set at 0, increase it to +3dB, and turn the volume knob on the sub down to get it back in balance with the rest of the system.
