A paedophile music teacher who sexually abused his students has been sentenced to more than 20 years in jail, with the judge describing his actions as "abhorrent" and "disgraceful".
The South Australian District Court heard Malcolm Winston Day, now aged 80, will die in prison after avoiding punishment for his crimes for decades.
After he was recently convicted and jailed for sexually abusing a young student in the 1980s, another victim, who had been disbelieved at the time, came forward.
Judge Jo-Anne Deuter strongly condemned Day's crimes and his subsequent denial to authorities.
"You presented to the world as a respected music teacher, an upstanding citizen and a family man, however this was a charade based on a lifetime of lies," she said.
The court heard Day was investigated by the education department in the 1980s, but denied any wrongdoing and the department found the allegations unproven.
Judge Deuter said it was a sad fact that sexual offending was "often swept under the carpet" at the time.
She said the victim was a promising young musician whose life had been forever changed by Day's predatory behaviour.
"She has carried the burden of your abuse and lies for over 40 years," Judge Deuter said.
The court heard the victim has struggled with depression, anxiety and post-traumatic stress disorder and turned away from music after the offending, which was a loss she also had to grieve.
"You poisoned her future for your own pleasure and then you went on to lie about it during the education department investigation," Judge Deuter said.
The court heard Day had a long and successful career as a music teacher and musician and was still supported by peers who provided character references to the court, including one who said Day was an "honourable" man and another who described the offending as a "lack of judgement".
Judge Deuter said she was concerned by the referees' lack of insight into the offending, with some saying the crimes occurred during a time in Day's life when he was "directionless" and on a "downward spiral" during his marriage breakdown.
"I make it very clear that the law does not, nor do I, regard the reasons put forward by your referees as reasons to sexually abuse children," she said.
Judge Deuter said despite Day's apology, she did not accept that he fully understood the wrongfulness of his crimes.
"I am still troubled by your lack of insight in relation to the effect your behaviour has had on your victim or your lack of insight into how, being in a position of trust as a teacher, it is completely wrong and abhorrent to encourage a sexual relationship with a student," Judge Deuter said.
Day, who watched the sentencing proceedings via a video link from jail, sat with his head bowed for most of the hearing.
After allowing discount for Day's guilty plea, the judge added another eight-and-a-half years onto his existing sentence.
Day's new jail sentence is 20 years and six months, with a non-parole period of 14 years.
