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From Paul Gold on reproducer calibration:
When setting up a turntable to check test pressings or deal with vinyl in a professional capacity it's a good idea to check it on a turntable calibrated to a standard reference level.
I've found that many don't know that a disk recording system is calibrated to a standard reference level. Just like open reel tape. The standard reference level for stereo recordings is 7cm/sec lateral. Cm/sec is a measurement of velocity. It's a speed measurement like miles per hour. And just like miles per hour you don't have to go 60 miles to be going 60 miles per hour.
There are calibration test records with tones at 7cm/sec lateral. Lateral essentially means mono. The groove moves from side to side (laterally) with correlated material and vertically with uncorrelated signal.
The only tone you need is 1k Hz. You can check frequency response with other tones but they should not be used to calibrate level.
Calibration is straightforward. Play the record and adjust the level until 7cm/sec equals your standard reference level on your meters (hopefully VU meters). Usually +4dBu.
It's difficult to find phono preamps that interface well in a professional audio system. Most are unbalanced -10dBv.
If you are stuck with a consumer style phono pre then using a -10dBv to +4dBu "bump box" will help. You can hang the meters from the output of the bump box and use it for level calibration.
If you haven't checked out records on a calibrated turntable I highly recommend it. It is very helpful when trouble shooting.