Love songs are a weird thing. By nature, they’re an expression of the most intimate of emotions, but the majority of the time they’re conveyed at a distance—sung from a radio, through headphones, or on a stage—and as a performance object to be heard by many, not one, thus stripping them of the personal emotion they ought to host.
But, for a little under two minutes in the middle of Macross Frontier, a love song connects.
Of the many love songs I heard and saw on television, the radio, and in movies during my childhood, two that have stayed with me to the present are “Lida Rose/Will I Ever Tell You” from The Music Man and “I Must Have Done Something Good” from The Sound of Music. In Morton DaCosta’s 1962 film adaptation, the former is delivered in a pointedly stage-like manner, as the Buffalo Bills and Marian sing their respective halves of the song in spotlighted circles on a mostly dark screen. It’s the modern love song, sung with a sort of passive-aggressive intent, but mostly thrown out into the void, waiting for a response from “that special someone”. By way of contrast, Maria and Captain von Trapp sing their love to each other in explicitly direct terms, bookended by spoken professions of love and a delicate kiss. 
Ranka Lee and Sheryl Nome’s episode 15 duet of “What ’bout my star?” is a love song in the tradition of Maria and the Captain’s, a no-holds-barred, unapologetically genuine expression of love through music. Alto has no choice but to submit.
As might be expected, all this makes Alto somewhat uncomfortable. But why? Of course, some of it is certainly the cognitive dissonance that arises from seeing one’s two love interests openly (and yet somewhat cordially) vying for your affections when you’re the indecisive member of the love triangle. And there’s also the base-level human embarrassment from being so blatantly called out in a public place. But, beyond that, there’s the unusual, powerful disruption of the normal arrangement of performance.
If “I Must Have Done Something Good” and “What ’bout my star?” are touchingly authentic (and, thus in my estimation, highly unusual among love songs), “Lida Rose/Will I Ever Tell You” represent the other end of the spectrum, a 50-year anticipation of the disconnected love songs of Top 40 radio and, more relevant, idol performances. “Lida Rose” visually represents the commonly agreed-upon structure of idol love songs: a solitary singer immeasurably far from the adoring chorus while still preserving an illusion of closeness.
The recorded or performed love song is disconnected; singer and audience are blocked apart by status, stage, and state. This holds doubly true for idols, created as they are to mimic intimacy while remaining distant.  An idol must belong to everyone generally, and no one in particular.
Thus, Ranka and Sheryl doubly (and jointly) burst through the falsity of the love song performed, through performance. These are no ordinary idols, and this is no ordinary idol song (nor an ordinary love song).
My favorite shot of the scene is the third in the above gallery, taken from Ranka’s POV and framing Alto through her fingers. The frame within a frame imitates the construct of performance , but that in itself is a fake because there no such convenient and comfortable distance for Alto in this moment—and Ranka has already made the decision, following Sheryl’s lead, to abandon the pretense of the idol’s solitary stage for a moment of sheer connectedness.
Love is not something that can be done at a distance.
And lest the all-important shift from the performed love song and the intimate love song of Sheryl and Ranka go unnoticed, Frontier contextualizes their non-performance within the diegetic use of Ranka’s episode five performance of “What ’bout my star?” @Formo on the screens of the hospital, a performance Sheryl characterizes as “fresh […] like a young, dreamy girl singing.”  But, just like Marian in “Will I Ever Tell You,” the Ranka on the screen (accompanied as she was by instrumentals that may as well have been non-diegetic, despite their pseudo-diegetic presentation) is singing a love song in isolation. Sheryl’s initiative appropriates the distant idol performance context and grounds it in the intimacy of physicality.
Ranka, ultimately, is still riding Sheryl’s coattails here, but that doesn’t reduce the authenticity of her own efforts to reach Alto through song. Even as an echo, her voice is no less real, no less potent than Sheryl’s.
And, together, even as their duet leans into the typical idol conventions of choreography and spotlights, it reaches out past the affectations and solitary nature of idoldom to pull Alto in. In fact, it’s really a violation of the very essence of idols, of the image, of the mask, of the performer. It’s true. It’s immediate. It’s powerful not because of the projection, but because of the reality. And nowhere else could this happen besides in a show that understands that we are alone, but come to love others in spite of the distances between us. That’s the true power of Ranka and Sheryl’s song.
So, to sum it up: this silly robot show understands love songs better than almost any other comparable thing. Sheryl is good. Ranka is good. Macross Frontier rocks.
 Robert Wise’s direction during this scene in the 1956 film further emphasizes the particularly intimate nature of the love song, as the backlighting turns the two lovers (wow, that is weird to type about a show from my childhood) into silhouettes and denies the audience entrance into the deepest parts of the relationship. These kinds of relationships are necessarily exclusive and personal, and Wise respects that—and creates something truly beautiful along the way.
 See, handshake events as (structurally) false displays of idol-fan relationship and idol dating bans.
 Also, yes, it’s a triangle. Like a love triangle.
 Formo being the Zentradi mall where Ranka performed. “@Formo” is the way the song is labeled by the official Macross Frontier Vocal Collection.