'The Sing-Off' Recap: Movie Theme Songs and Big Battles Hit Week 2 (Video)

THR sings the soaring high notes and points out the sadly flat moments throughout the second week of NBC's revived a cappella competition.
acoUstiKats on "The Sing-Off"

While the first week of The Sing-Off was full of heartwarming moments (she said yes to that proposal, after all), the following week of competition felt more severe, swiftly trimming a cast of seven a cappella groups down to three, ahead of its finale on Monday night. Still, the journey was pleasant, thanks to movie theme songs, choreography lessons and one particular, pantless performance.

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Here's what happened on the second week of The Sing-Off:

Monday night's one-hour episode was themed "My Generation" (which really was just the second hour of last Thursday's episode showcasing No. 1 hits), kicking off with a medley of The Who's "My Generation," Queen's "We Will Rock You" and Imagine Dragons' "It's Time." (We notice that season four's opening numbers aren't as cohesive or climactic as previous seasons'; sure, groups aren't judged based on these performances, but it's a missed opportunity to not kick off with the show's bang, especially with so many singers onstage.)

With Ben Folds as the backstage mentor, the country professionals of Home Free delivered on the toe-tapping Johnny Cash's "Ring of Fire" and performing arts high school group Vocal Rush showed off multiple soloists on Bonnie Tyler's "Holding Out for a Hero," but all-female group Element couldn't get past their cookie-cutter impression on The Supremes' "You Keep Me Hangin' On," and VoicePlay couldn't sell No Doubt's "Don't Speak," an odd song to represent the '90s, if anything. Still, Element found themselves facing Vocal Rush in the evening's Ultimate Sing-Off (for what reason, we'll never know) for a battle on Destiny's Child's "Survivor." The high school students schooled the New York City working women with their Oakland grit, and Element was sent home.

Watch Vocal Rush cover the '80s hit below, complete with a rap bit:

Wednesday night's two-hour episode featured all six remaining groups for an evening of movie theme songs, beginning with, as we guessed weeks ago, "I've Had the Time of My Life" from Dirty Dancing. With Jewel stepping in as mentor, the night's highs included the very consistent Home Free adding a '50s-style interlude to Roy Orbison's "Pretty Woman," the energetic and entertaining Ten with a suspenseful cinematic rendition of "Skyfall" by Adele, and the young but growing competitor Vocal Rush with an emotionally authentic arrangement of "Against All Odds" by Phil Collins.

The lesser-praised performances of the night included the acoUstiKats with Bob Seger's "Old Time Rock 'n' Roll" -- though they took off their pants and wore the signature Risky Business sunglasses, they kept switching genres and slowed the tempo down to a ballad, to the judges' dismay. They also didn't favor The Filharmonic's "I Don't Want to Miss a Thing" by Aerosmith due to loose harmonies, or VoicePlay's "Don't You (Forget About Me)" by Simple Minds, which only glossed over the beloved la-la-la's of the Breakfast Club anthem.

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All six groups then paired off for three battles (which they previously rehearsed, leading us to question the validity of all the Ultimate Sing-Offs and why Vocal Rush was in the bottom the night before …), merging more or less into supergroups. VoicePlay and acoUstiKats' "Eye of the Tiger" from Rocky III felt predictable in comparison to Vocal Rush and Ten's "Fame," which showed off their most powerful soloists and mixed in a Latin section, and Home Free and The Filharmonic's "I'm Alright" by Kenny Loggins, complete with the two groups teaching each other choreography (including the Caddyshack gopher move), engaging in a battle of the beatboxers and jamming down a soul train -- a humorous performance that had Jewel endlessly giggling, and sealed the eliminated fate of VoicePlay and acoUstiKats.

Watch Home Free and The Filharmonic battle and blend below: 

With only four groups left, Thursday night's one-hour episode featured a set list picked by the judges, with Nick Lachey as rotating mentor. After a relatively strong opening of Florence and the Machine's "Shake It Off," Home Free entertained with Zac Brown Band's "Colder Weather," despite the initial pitch problems, and Vocal Rush rose to the instrument-heavy challenge of Fall Out Boy's "My Songs Know What You Did in the Dark." Ten's predictable delivery of Ike and Tina Turner's rendition of "Proud Mary" had Jewel questioning whether they could tackle songs outside the gospel genre, and The Filharmonic couldn't lock in a memorable high moment on the Four Tops' "Baby, I Need Your Loving" (an off-center song choice, in comparison to what the other groups were assigned.)

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The Filharmonic battled Ten on The Clash's "Should I Stay or Should I Go," and while the '90s-inspired Filipino boys strategically switched genres with every verse, the gospel-infused group instead kept raising the energy level and, as Shawn Stockman put it, took everyone to church. In the end, Ten emerged victorious, becoming the third group to join Home Free and Vocal Rush in the finale.

Watch the four groups perform "Shake It Off" below:

While the revived Sing-Off has enjoyed its changes, we're sorely missing the challenges of the mashup (a la Pentatonix's conversational blend of Kelly Clarkson's "Since You Been Gone" and Cee Lo Green's "Forget You" in season three) and the medley (we're still raving about the Beelzebubs' medley of The Who's hits during season one). One of the best things about a cappella music is not only swapping genres mid-song as this season's competitors often have, but also to collage songs together and create a new story. We're hoping for one of these in next week's final episode -- amid holiday songs with Lachey and the judges, of course.

The Sing-Off two-hour finale, with guests 98 Degrees and Pentatonix, airs Monday at 8 p.m. on NBC.

What did you think of The Sing-Off's second week? Which groups are flying high and which are falling flat? Sound off in the comments below.

Twitter: @cashleelee