Concert Pitch A 440 (A above middle C vibrating at 440 times per second) has been universally accepted as the pitch to which all instruments should be tuned. This standard ensures that all musical instruments throughout the world will play notes of similar pitch. Apart from the fact that pianos are designed and built to sound their best when tuned to A440, it is also very important to musical ear-training. Loss of string tension caused by tuning neglect will ultimately result in a drop in pitch. The amount of extra tuning involved in pitch raising will increase proportionately with the amount of lost string tension. Extra pressures created during the pitch-raising process causes readjustment of the iron frame, sounding-board, ribs etc. resulting in the piano quickly losing some of its initial tuning. A second and sometimes third tuning may be required to establish A 440 and at the same time provide a stabilized tuning.