"He listened to the recording and and heard noises consistent with them having sexual intercourse,'' the police caption summary said.
The police believe Hamid-Zadeh attacked Mr Razani with two knives sometime after 5am but an ambulance was not called until after 7am.
When ambulance and police staff arrived, they found the woman dripping blood in the Quadrant foyer.
Police went up to the 23rd floor and found 30-year-old Mr Razani stabbed to death in the bedroom.
Hamid-Zadeh was sitting in the lounge, nursing an injury to his hand. He was later taken to hospital and required surgery. Police also found two knives, one of which had a 28cm-long blade.
Hamid-Zadeh's lawyer Belinda Sellars argued that provocation should be taken into account at sentencing.
The partial defence of provocation has been repealed by Parliament but judges can still take it into account at sentencing.
Ms Sellars said her client lost self-control when he discovered the woman had been sleeping with Mr Razani.
Ms Sellars said there was no planning or premeditation involved in the murder, he had shown remorse and had pleaded guilty at an early stage.
Crown prosecutor Aaron Perkins said the case did not warrant the judge considering provocation.
"The prisoner may feel aggrieved but the level of infidelity could hardly be seen as a unique occurrence.''
He said it was a brutal attack which left Mr Razani 42 cuts to his body and 17 stab wounds, two of which went through his chest and lungs before hitting his spine.
"One does not need to be a physician to know that they almost passed right through the body.''
Mr Perkins said Hamid-Zadeh should receive the full 17 year minimum non-parole period for his "fierce'' attack.
Justice Patricia Courtney said she found the attack showed a high level of brutality and callousness which was witnessed in part by the woman living at the address.
Justice Courtney took two years off the sentence for the provocation aspects and a further two and-a-half for his remorse, previous good character and the fact that prison in New Zealand would be hard for him as he spoke little English and had no family here.
In total the no-parole period is 12-1/2 years.
Outside court the officer in charge of the case, Andy King, said he was pleased with the result and the early guilty plea which ensured the woman did not have to give evidence at trial.
He said police would be in touch with her and let her know of the result.