A New Zealand Opera School Master Class at Whanganui Collegiate's auditorium was exactly that: a vocal class led by a maestro.
The maestro vocal coach at Friday night's class was Australian Glenn Winslade, a fine and infinitely patient tutor who is renowned as one of the finest teachers of vocal technique in the world.
With a strong presence, Winslade had the capacity audience riveted.
The world-acclaimed tenor said sadly his stellar career had ended with an accident onstage with the Vienna State Opera during a performance.
His character had been suspended above the stage, seated on a sofa.
A explosion destined for the back of the sofa went horribly wrong and hit Winslade in his spine, resulting his voice completely failing from then on.
"I knew I had to retire. It was a very tragic time for me."
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After returning to Australia he was referred to an ENT (ear, nose and throat) team in Adelaide who were "way ahead of anyone in the world in vocal research".
"Though my singing voice returned I decided to stay, teach and scientifically research the voice," Winslade said.
"Always remember," he told the four students on stage with him on Friday, "your body is an instrument … you must inhabit it always."
In one-on-one 20 minute lessons the four students were put through their vocal paces, first singing a complete aria then repeating phrases again under Winslade's sure and thorough tutelage.
The results were staggering as Winslade rearranged their bodies and breathing, from their pelvises to their ears.
Soprano Carla Camilleri gasped with astonishment as Winslade led her into breathing and body changes, completely transforming her performance. Tears glistened in her eyes as Winslade assured her that she had a beautiful voice and, with the right physical work with her body sustaining her breathing, she would be unstoppable.
And soprano Michaela Cadwgan was impressive as she too submitted to the rigorous tutorial.
Winslade told her she had a glorious voice and to work hard so technique became second nature.
"Develop your technique so you can perform onstage without nerves and be confident in your voice."
Baritone Samuel Downes, who towered onstage like a rep men's basketball player, had a voice that initially reverberated throughout the auditorium.
But by the time Winslade had tweaked his chin position, his neck and even his ears, Downes' voice had deepened and flowed with ease. His is a voice that will resound around any opera house, no matter how big, in the years to come.
Winslade closed by saying how delighted he was to be at the school.
"This is a very fine school and these young singers are fortunate to be here."