Sound engineer Olivier Warusfel spends most days sequestered in an audio cave with a computer.

NPR: IRCAM: The Quiet House Of Sound

Jesse Baker produced the story of our visit to West Virginia, and Rob Byers was our sound engineer.

NPR: Life in a Mining Town

Tracey started her career at the BBC as a sound engineer.

BBC: Tracey Logan presents Go Digital

His dream was to become a sound engineer.

FORBES: How Alex Ljung Conceived SoundCloud And Plans To Make It Rain

Our sound engineer was Rob Byers.

NPR: Economic Check-Up in Broken Bow

The explanation for why there's a difference in lengths requires us to take a radio trip around the sun (virtually, of course, in my radio piece, with sound effects that come entirely from my mouth plus a little boost from my engineer Manoli Wetherell).

NPR: Not All Seasons Are Created Equal

When Malaco bought Muscle Shoals Sound, it hired Jackson to write songs, said Wolf Stephenson, Malaco's vice president and chief engineer.

NPR: Rock And Soul Songwriter George Jackson Dies At 68

Of course, good sound is subjective, so the app sets a concrete metric: It attempts to replicate exactly what an audio engineer hears inside a recording studio.

WSJ: Studio Sound to Go | App Happy

"We wanted to make it sound a bit like a Neil Young album, " says O'Brien, who recorded Becoming a Jackal with engineer and co-producer Tommy McLaughlin.

NPR: First Listen: Villagers, 'Becoming A Jackal'