Voice recording booths: Keepsake found in Cardiff shop
They have been described as audio postcards, soppy spoken love letters and mementoes from a day out.
Voice recording booths were popular in the UK and USA between the 1930s and 1970s and were fixtures at train stations, seaside arcades and tourist attractions.
While the discs they created have largely disappeared, one featuring women singing to a baby found in a Cardiff charity shop was the catalyst for the rediscovery of a long-forgotten way of communicating.
The story is told in a Radio 4 podcast called Keepsake For My Lover.
It began when the boyfriend of BBC radio producer Hannah Loy came across an old recording while sifting through records in a Cardiff charity shop.
"When he got it home, it actually played and we heard two women singing to a baby," she said.
"It was so exciting and evocative to hear those voices from the past, we created a whole back story to their lives."
Along with presenter Janine H Jones, Ms Loy began looking into the history of the booths, summing up their role in British culture by adding: "If you've seen Brighton Rock you'll know what we mean."
The 1947 movie, based on a Graham Greene novel, is a gangster film where a voice recording made at a fairground plays a central part in the plot.
One of the characters does not have a gramophone to play it on, with the content only revealed towards the end of it.
While most traces of the booths have long-since disappeared, the pair found details of somebody who still repairs them, living near Washington DC in the United States.
"Luckily, Janine was going on a trip to the states anyway so that's when everything fell into place," Ms Loy said.
"She spoke to everyone she could over there about the discs and the booths and came back with some amazing recordings."
Booths had a strict time limit and you spoke or sang when a green light came on.
'Power and timelessness'
Ms Loy added: "I think that flummoxed people, it was like a performance, people got tongue tied or their minds went blank.
"Often they spoke about mundane things."
To try and recreate the feeling of the booths, the pair set one up at the Wales Millennium Centre in Cardiff Bay, putting on a time limit and one chance to record.
"People engaged with it straight away but what struck us was how similar some of the recordings were to the ones from over 60 years ago featured in the documentary," she said.
The podcast Keepsake for My Lover is part of the Seriously podcast collection for Radio 4.
"(It) emphasises the power and timelessness of recorded speech and the beauty and significance in mistakes and the mundane," Ms Loy added.
"[It is] particularly poignant now, when we live in a world where everything can be airbrushed, faked and edited."