Perfect pitch is the rare ability to accurately recreate or identify specific pitches or notes.  Some musicians may come close with relative pitch, but still require the benefit of a reference.  Musicians regularly performing on stage are well aware of the acoustic challenges in hearing instruments of the ensemble or band. 

The use of monitor speakers or in ear monitor headphones have become standard practice to aid in the provision of the required reference – enabling a vocalist to hear the piano or guitar as pitch reference for example.  Working with a sound engineer that through first-hand experience understand these challenges on stage will give any musician a competitive advantage.  A sound engineer cognoscente of the challenges musicians experience on stage, will rather adjust the monitor mix when a vocalist is not singing on the correct pitch, than dismissing the vocalist as not being able to sing on key.  Similarly, timing between musicians can also be improved when they can follow the same rhythmic reference such as a percussion instrument.  Contact Joyful Audio eNgineering if you prefer to work with a sound engineer that fully understand the challenges on stage, someone that can make you sound amazing.