Vid is very misleading. What he is doing is relieving spoke wind up (torsion) not ‘tension’. It’s not a very effective method of stress relieving a wheel either as you don’t increase the tension on the spokes enough. The pinging noise is spokes which have torsion returning to a neutral state. You should release torsion when building the wheel by backing off the nipple a bit until it takes equal force to turn it in either direction – about 1/8 to 1/4 turn but depends on the spokes and the tension.
A few things you should do to help ensure long life of a wheel.
– form the j-bend. Press down on the spoke elbow as it exits the hub flange so that the spoke sits flat against the flange.
– put a dowel where the spokes cross and twist the spokes to form a permanent bend at the cross.
These two things mean the spoke is formed in the right shape for the wheel – the spoke runs in a straight line from the flange to the cross then to the nipple and will not be springing in and out of shape over time and thus fatiguing.
– the final thing is proper stress relieving. This is done by squeezing opposing pairs of spokes to momentarily increase the tension on the spokes significantly. This needs to be done quite hard – pretty much as hard as you can squeeze them – wear gloves. This process relieves the internal stresses in the spokes (at the elbow, where the thread has been rolled) and will greatly improve the life of the wheel.
If you do all of these things and it’s round, true and at a high and even tension your wheels will be about as good as anyone can build them.