It's evening and my three-year-old son is overtired, the hour well past his bedtime.
After some negotiation and much protest, we go to his room. I read a Dr Seuss book, watch him carefully arrange his fluffy toy friends in bed, give him a drink of water, tuck him in, and turn off the light.
"Let's listen to some music," I say, switching on the digital radio and taking a seat in the armchair beside him.
It's code, of course. "Listen to some music" means "go to sleep".
But it's not just my son who nods off — I do too.
Initially, I put it down to sheer exhaustion; the cumulative effects of parenting a spirited toddler.
But then I wonder: is there more to it? Does the music itself play a role?
The kids at my son's day care have naptime in the afternoons, and this includes the playing of music.
The educators say it helps them relax.
We've used lullabies to soothe young children for thousands of years.
One of the earliest recorded lullabies is etched into a 2000-year-old Babylonian tablet.
The children's radio station in my son's room plays lullabies in the early evening. This is followed by soft classical music until midnight, and then ambient sounds and field recordings until dawn. It's a tailored playlist designed to lull children to sleep, keep them asleep, and help provide a deep slumber.
But the jury is out as to whether or not music will help.
Music and medicine
When we fall asleep our brain cycles through different phases from wakefulness to non-REM sleep and then REM sleep.
These phases produce distinct changes in our brainwaves, and physiological signs such as eye movements, heart rate, blood pressure and levels of consciousness.
This article contains content that is not yet available here.
YouTube is awash with sounds purported to inspire us to slip into sleep, including eight-hour recordings of theta and delta brainwaves.
A recent Danish study found music may help the recovery of patients in an intensive care areas — where they are most in need of the restorative properties of sleep.
Rosalind Elliott, a clinical nurse specialist in Sydney's Royal North Shore Hospital intensive care unit, encourages her patients' families to provide their loved ones with their preferred music in order to promote relaxation and sleep.
"Medications such as benzodiazepines and atypical antipsychotics are often used to promote sleep in the field of general sleep medicine, but these have been shown to be harmful to the critically ill in both the short and long term," she says.
"Non-pharmacological interventions such as music offer a safe alternative and are useful adjuncts to the therapeutic efforts of the critical care nurse to provide comfort and rest."
But Moira Junge, a psychologist and board member of the Sleep Health Foundation, advises caution.
"The new Danish study didn't objectively measure sleep; there was a self-report questionnaire which is a subjective estimate."
Dr Junge also worries the carers, not the patients themselves, may have made the estimates.
"This is because most critically ill people can't really estimate their sleep quality or quantity."
Do you sleep with Ed Sheeran or Mustang Sally?
About 40 per cent of people have inadequate or disrupted sleep due to a medical condition or sleep disorder.
Many studies have shown that music can help adults with chronic sleep disorders such as primary insomnia.
Michael Gradisar, a clinical psychologist from Flinders University, has worked with adults and teenagers experiencing insomnia.
Professor Gradisar says he recommends his clients use passive technological activities such as listening to music before bed, and even in bed.
"Over the years, I've heard many adults and teenagers say that when they try to fall asleep at night, they worry about things that happen during the day and things they still need to do," says.
"This concurs with research showing that evening is one of the peak times when people ruminate."
Danny Eckert of Neuroscience Research Australia also believes music before sleep can have positive benefits for those having trouble drifting off.
"Listening to music as part of the pre-sleep routine, particularly music with an underlying rhythm of about 60 beats per minute (bpm), similar to human heart rate, can improve sleep quality and quantity in some people with sleep problems such as insomnia," Professor Eckert says.
Meanwhile, Ed Sheeran, Coldplay and Brian Eno were the most popular contemporary artists, and Bach, Mozart and Chopin the most popular classical composers to fall asleep to, according to a recent study from the UK.
Music is soothing but there's no easy fix
Anecdotally, my 87-year-old mum plays a Greek radio station on low volume through the night. She says it helps her sleep since Dad died.
With music in the air, she's suddenly not so alone anymore. And Mum is also a world-class worrier.
"Listening to music could be helpful to the person who finds themselves worrying when lying in bed in dark silence," Professor Gradisar says.
"Not only would music help as a distraction, but it could also create a more positive association with going to bed."
Unlike video games or certain smartphone apps, listening to music doesn't require the user to interact with the device, and so qualifies as a passive activity.
"This can allow sleep to come more easily," Professor Gradisar says.
But the jury is still out on the benefits of music and sleep, according to Dr Junge.
"There is currently no recommendation via the Sleep Health Foundation to utilise music during sleep.
"Our current recommendation focuses on reducing vigilance, worry, and hyper-arousal, and there are quite large differences in people as to how to best reduce this 'wired' state."
She cautions people who are looking for a cure or treatment plan for better sleep that it's unlikely to be just one thing that will help them sleep better.
"It's a bit like getting fit and losing weight: it takes time, effort, and is multi-factorial," she says.
Where's my John Coltrane?
Ultimately, the choice is up to the individual.
For my family at least, music seems to have been an easy, cheap, and effective way to improve our sleep.
And when you're the parent of young children, that's everything.
As for my son, I recently switched his regular radio station from the children's channel to jazz — less Twinkle, Twinkle, Little Star and more dirty saxophones.
When my wife heard an especially energised bebop rendition recently, she changed the channel back.
But my son sat bolt upright in bed, pointed an insistent finger at the radio, and demanded to have his John Coltrane restored.
And I was rather proud of that.