Headphones
Headphones were headwear speakers that were worn over the wearer's ears and used to play audio privately.
Some headphones actively cancelled out the waveforms of undesired external noises. These were called noise-cancelling headphones. (AUDIO: Dead Media)
BOSS used a form of headphones to condition and hypnotise humans such as Jocelyn Stevens and Ralph Fell. (TV: The Green Death)
Professor Grisenko enjoyed listening to Western music, such as Ultravox and Duran Duran, through his Walkman headphones while stationed on the Soviet submarine the Firebird. (TV: Cold War)
In 1984, Tegan Jovanka attempted to call out to a man using a metal detector on the mud banks of the River Thames while being pursued by Lytton's policemen. However, as the man was wearing headphones, he could not hear her and was shot by the fake policemen. (TV: Resurrection of the Daleks)
The Snowcap Base in Antarctica used headphones to communicate with the crew of the Zeus IV and Zeus V. (TV: The Tenth Planet)
Students of Deffry Vale High School used headphones for lessons. These were used by the Krillitanes to entrance them into cracking the Skasis Paradigm. (TV: School Reunion)
The Tenth Doctor witnessed a man influenced by the Master's Archangel Network wearing headphones and tapping with the rhythm of the Drumming. (TV: The Sound of Drums)
As he was outside using his telescope, Wilfred Mott missed the arrival of the Adiposian First Family's nursery ship over London as he had his back turned and was wearing headphones. (TV: Partners in Crime)
During the Monk invasion, a resistance group led by the Twelfth Doctor broke into the Cathedral. The members of the resistance group wore headphones which played a recording by Bill Potts reminding them of the Monks true nature and why they are fighting them, in order to resist the True History which was being transmitted from the Cathedral. (TV: The Lie of the Land)
Max Collins played Xbox using headphones, so as not to be detected by his parents. (PROSE: Joyride)
Max listened to internet pornography downloaded onto his computer through headphones. (AUDIO: torchwood_cascade_CDRIP.tor)
Elliot Northover used headphones to listen to audio books, as he found it easier than reading due to his Dyslexia. (TV: The Hungry Earth)
When Tracey's belongings were stolen, all he had left were a pair of Walkman headphones. (PROSE: Hospitality)
In 2079, technicians and communications officers on board Space Station W3 used headphones in the Operations and Communications Room. (TV: The Wheel in Space)
Passengers aboard Crusader 50 shuttle buses received headphones for listening to entertainment channels. (TV: Midnight)
On board the Hyperion III, Melanie Bush listened to tape recordings through headphones to help her exercise in the space-liner's gymnasium. (TV: Terror of the Vervoids)
Earphones
Earphones, also known as earbuds, were a smaller, portable form of headphones fitted to the outer ear rather than worn over the head. Like headphones, these were also primarily used for listening to audio privately.
While working for Harold Saxon, Miss Dexter used earphones to listen in on phone calls between Martha Jones and her mother Francine Jones. (TV: 42, The Sound of Drums)
In 2007, C'rizz once attacked bystanders in King's Cross station. Luke Tillyard, discovering that Charley Pollard was running from C'rizz, used the earphones from his MP3 player on C'rizz which rendered him unconscious. (PROSE: Salva Mea)
When a plate-sized Virtual ship crashed in London in 2011, the Virtuals escaped by uploading themselves onto the internet via a music track called "Alien Infiltration". This caused several people who listened to it through earphones to enter into a trance and walk out into the streets until the Eleventh Doctor deleted the Virtuals from the internet server and sent them back to their own dimension. (COMIC: Sound Bytes)
After being caught listening to music on earbuds at school, Ralph used Mkali technology to send out a jamming signal to all other earbud devices. This interfered with the brain waves of his classmates, allowing Ralph to control them through their earbuds until the Twelfth Doctor intervened. (COMIC: Fear Buds)
The C-Fish was a portable music player developed in the 2020s which had tiny earphones. Jack Harkness stored a C-Fish X20 in a locker at King's Cross as a Time Agent. He retrieved it in 1967 when he was working for Torchwood Three, just because he wanted to listen to some music. (PROSE: Trace Memory)
Other realities
On Pete's World, the EarPods produced by Cybus Industries served as that universe's equivalent of the earphones and headphones of the Doctor's universe, with similar functions such as allowing their wearer to listen to audio and communicate. Like earphones, the EarPods were also fitted to the wearer's ears. However, the EarPods were much more technologically advanced, also allowing their wearers to download information into their brains as well as serving as covert mind control devices. (TV: Rise of the Cybermen, The Age of Steel), (PROSE: EarPod)
In the Shadow World, the Twelfth Doctor used earphones to listen to an audio transcription of the Veritas text via a laptop, which he could not read due to his blindness sustained at Chasm Forge. (TV: Extremis)