Evanescence's Synthesis album mainly comprises orchestral re-imaginings from the band's catalog. However, there are two new songs on the record: "Imperfection" and "Hi-Lo."

This track was originally written by Amy Lee as the first collaboration between her and Will "Science" Hunt, when penning material for Evanescence's third, self-titled album. Speaking to the 105.7 The Point, Lee said:

"[The song] 'Hi-Lo' we've had in the bank for a long time. I wasn't quite finished [writing it before], but it's just a song that never fit anywhere that I've been holding on to and waiting to find its right home for 10 years. So it's this weird thing that I feel very close to already that I've had to listen to with my family and my friends to now finish it out and have the orchestra on it. That's what it needed — it needed that beautiful, luscious emotion that [longtime collaborator, orchestra arranger and composer] David Campbell put on there. But I wrote that song with our producer on this album, the guy that did all the programming, Will [Hunt, not to be confused with Evanescence's drummer, also named Will Hunt]."

The song features a guest performance by famed violinist Lindsey Stirling. Speaking to Stencil Mag, Amy Lee explained:

"Once we got most of 'Hi-Lo' recorded, it had this interesting long instrumental part without a lead vocal point. Instead of doing what I usually do and writing vocals to go on top of it, I thought it would be a perfect moment for a guest solo. I had a couple of people in mind but Lindsey was the obvious, natural choice. She was in LA and we were recording at Spaceway in Fort Worth, so after telling her what I imagined she demo-ed out her part and it was already fantastic. Then she recorded it and we got the track back and were so excited. It took it exactly where I wanted it to go. She's a beast!"

"Hi-Lo" was the song's working title, which Amy Lee decided to retain. It comes from the lyric "Don't you know we could be. High or Low."