mutter machine
n. A machine that plays office background sounds, such as chatting and laughing.
Why buy this new stuff at the taxpayers' expense? Are there no old Birtspeak tapes? There are quite a few human mutter machines already working for the BBC and being paid quite a lot of money. They could be pressed into service; alternatively, the BBC could use some of the canned hysterical laughter, which seems to be activated whenever someone on the telly says anything which is even mildly amusing.
—Ron Ferguson, “Savour the sound of silence, a victim of daily throbbery,” The Herald (Glasgow, Scotland), February 17, 2000
Bob Hockey, a professor of psychology at Hull University, has studied the effects of noise on performance and says that noise can be a real problem in open plan offices. He says: "The reason for introducing white noise, such as the sound of a gushing waterfall, is that it stops people being distracted by specific sounds. People get used to white noise very quickly."

But what about the complaints made by the BBC workers that they felt lonely and isolated because it was so quiet?

Hockey doubts very much that the "mutter" machine will help with feelings of loneliness.

"A machine which makes you think your pals are just round the corner does not sound like a cure for loneliness. It seems a bit silly and I should think it needs some serious research. I wonder if a new seating arrangement might work better?
—Gabriel Roberts, “When silence isn't golden,” Birmingham Post, January 05, 2000
1999 (earliest)
Accountants at the BBC have complained that their new office is too quiet but instead of being told to talk among themselves as they add up figures and pore over contracts, they are getting a £2,300 machine to do it for them. …

The BBC bought the accountants a 'mutter machine' to provide the reassuring background of office banter and occasional bursts of laughter.
—Ed Harris, “Too quiet in the office,” The Evening Standard (London), October 14, 1999