Step No. 4
Leveling the head
If the counterhoop is flush or level, and the lip of the bowl is flat and in plane, you can use a product like the TAP™ Head Gauge (ca. $20.00) to get the head somewhat balanced with relative tension at each lug, a process called leveling. This process will get you in the ballpark, but only works well if the counterhoop is flush, and the lip of the bowl is flat and in plane. If the counterhoop is not flush or the lip of the bowl is not flat and in plane, this process does more harm than good, in which case the counterhoop and/or the bowl needs to be fixed or replaced. If you know the counterhoop is not flush, or that the lip of the bowl has issues, avoid this process and go on to the next step and hope for the best.
Make sure that the drum itself is level and pick a point at which to begin. Position the block on the head so that the pointer (set screw and cap-nut) is centered in the middle of the counterhoop directly in front of a lug. Adjust the pointer so the cap-nut barely touches the rim and lock it in place with the wing-nut. Following the cross-tuning sequence below, place the gauge on the head and adjust each lug until you do not see any daylight between the block and the head.
diagram courtesy of the Yamaha Corporation
MAKE ADJUSTMENTS IN SMALL INCREMENTS ONLY. Repeat this process until all lugs have been leveled. ALWAYS make sure you keep the drum within its MSR.
LEVEL
NOT LEVEL
Move the pedal into mid playing range and strike the drum in the normal striking position with a medium hard stick a few times softly and once loudly. Place your ear close to the head and listen for clarity of pitch and near harmonic overtones. The idea throughout the tempering process is to find the differences in pitch at each tension lug point and correct them until the pitches of the soft strokes and loud stroke match. More than likely the drum will still need more tempering. More often than not, after measuring equally at each tension rod, the pitch at each rod will be extremely different and the head will be completely out of tune. This is usually due to a counterhoop that is not flush or the lip of the bowl is not flat and in plane. The maker of this product states that additional head clearing may be needed after initial leveling.