Tom Mitchell has deconstructed the works of Radiohead, Coldplay, Kings of Leon, Sigur Ros and many others.

Ellie Gibson finds out why the Gregory Brothers trawl the internet for accidental music video stars and learns the art of ruining a good tune.

The BBC visits and talks to some of those who marry technical knowledge with musical virtuosity.

All those hours spent alone, in a back room or a basement, surrounded by expensive equipment. All that time spent learning, making mistakes and improving, finding out what to do and how to do it.

Who does that describe? Geeks, hackers, makers? No. Musicians.

Combine them and what sweet music they make. Sometimes. At other times they use technology to make something much funnier.

Take The Gregory Brothers. The four-piece plays all kinds of music when gigging but on the web have married their musical and lyrical skills with auto-tune software to make the news more interesting.

In a series of videos, the various members of the Gregory Brothers sing along as auto-tuning is applied to the words of people in the news.

Auto-tuning began as a useful tool for record producers to ensure the voices of their stars hit all the right notes by artificially correcting pitch. The Gregory Brothers use it in a more extreme way to turn speech into singing.

The results involve President Obama singing about knowing whose "ass to kick" but their most famous work was the Bed Intruder Song which came out of the energetic interview Antoine Dodson gave to news programmes after an attempted attack on his sister.

Guitar hero

Then there are those who swap the sonic stylings of rock and pop stars for something more discordant.

You might be forgiven for thinking that it would be easy to simply overdub the audio and make any one sound like they couldn\'t carry a tune in a paper bag. And it is.

But the people perpetrating these "shreds" are not interested in what\'s easy.

The key to a good shred is making it sound authentic - and that can involve a lot of time, technology and tinkering.

Perth-based Tom Mitchell, aka allergonoise on YouTube, has deconstructed the works of Radiohead, Coldplay, Kings of Leon, Sigur Ros and many others.

It can take time to find the right target to shred, said Tom Mitchell

Why those particular bands?

"It\'s usually nothing to do with my personal taste," he said "I find I pick the bands that maybe take themselves a bit more seriously than others."

Explaining how he got started, he said: "My flatmate showed me a couple of the original shreds of Eric Clapton and others, and I thought it was one of the funniest things I\'d ever seen."

"I was really impressed and amazed by them," he said.

At the time he was studying audio production and had been playing the guitar for over a decade. Watching those original shreds, he remembers thinking: "I might be able to do that."

At first it was a joint effort with his flatmate and friends and those first few shreds were put together using Apple\'s Garage Band program. Soon it turned into a solo project and his shreds became more intricate.

"I try to use a microphone that\'s like their microphone," he said, "and pretend I\'m the sound guy at that gig and how I would make it sound like that. I listen for the acoustics at that venue, for every single element that makes that sound."

Poor shreds lack that reality, he said, adding that they sound too "roomy" - by which he means they sound like they are being recorded in someone\'s back room rather than a sweaty club, cavernous concert hall or open-air stadium.

The music Mr Mitchell swaps for the original also cannot be any old strumming or plucking. What you hear, he said, has to match what you see.

"I watch the video clip a few times and learn how to play the song properly," he said, "and then just do something to put me off like play it upside down but while I\'m doing so I\'ll listen to the original song.

"I know what I\'m doing but I don\'t play it right," he said.

The results are eerily authentic.

A successful shred is one in which the listener genuinely wonders if what they are hearing is real. For the dedicated shreds-maker an e-mail asking if it is fake, or from someone who says they were at that gig and do not remember it sounding like that is as good as a round of applause.

Practice run

In that sense Santeri Ojala, aka StSanders on YouTube, is a master of the art of the shred.

Watch his deconstructions of The Beatles, Queen, The Rolling Stones and Kiss and it becomes hard to remember the lyrics of the original so closely are the nonsense words matched to the lip and mouth movements of Lennon, Mercury, Jagger and Simmons.

"The first one was really hard to do," said Mr Ojala, "I spent most of the summer just rewinding the video to get it right."

Mr Ojala was prompted to shred by a video of guitar legend Steve Vai.

"I was watching a video of him without sound and I noticed how goofy he looked," he said. "I just decided to make it even more goofy."

For Mr Ojala a shred must do more than make people laugh. It must also offer something to those who know their way around a guitar.

This means, he said, that the bum notes and crashed chords he swaps for the real notes must be authentic and resemble the kinds of mistakes everyone makes when learning to play.

"I think that\'s why they like it," he said, "because they know that part is hard to play."

Although Mr Ojala is very well known on YouTube for his shreds, it will remain, he said, a hobby until he can make it pay.

Also, he said, finding good targets is tricky. Though he has an inkling about who might be next.

Justin Bieber.

"It\'ll be a hard one because I genuinely think I could not do worse," he said. "It\'s going to need something different from me. I might attempt to make him look really cool."