vocals span from the note of A3 to E5. Built on a bouncy beat, "Radio" is instrumentally complete with a Roland TR-808 drum, bass instruments, and synthesizers. Several music critics, including Ben Westhoff of OC Weekly, noted that "Radio" bears resemblance to Rihanna's single "Umbrella" (2007) as they are both set to 1980s-style synthesizers." Similarly, James Reed of The Boston Globe wrote that "Radio" seems to be like the latest electro-pop confection from Rihanna. Darryl Sterdan of the Canadian website Jam! wrote that "Radio" sounds like a record Madonna would sing because of its electropop and dance-pop musical styles. Serbian newspaper Alo! suggested that the melody was plagiarized from "Aspirin" by Serbian singer Seka Aleksić, and claimed that the songwriters Filip Miletić and Miloš Roganović would sue Beyoncé; the claim was met with ridicule from other Serbian media. The believability of the song's lyrics, which conveys love testaments as well as its timeless endurance, sung on sensual vocal arrangements by Beyoncé, who additionally adopts a sneering attitude, demonstrates her alter ego Sasha Fierce. Lyrically, "Radio" explores the relationship between Beyoncé as the female protagonist and the songs played on the radio, shown in the lyrics: "You're the only one that Papa allowed in my room with the door closed / We'd be alone / And Mama never freaked out when she heard it go boom / 'Cause she knew we were in the zone". Amy Linden of Vibe magazine felt that "Radio" could make an ideal "valentine" song because of its lyrical content. Critical reception "Radio" received generally positive reviews from contemporary critics, who praised Knowles's brief departure from usual R&B style as well as the believability and originality of the song. Alexis Petridis of The Guardian noted that though the 1980s synthpop mode of "Radio" may not be as well suited to Beyoncé's voice as the old soul samples contained in "Crazy in Love" (2003) and "Suga Mama" (2007)", there is no denying that "Radio" is an "irresistible pop song". Colin McGuire of PopMatters highlighted Knowles's diversion from her usual R&B style, writing that "Radio" is "a bit of a novelty act " which takes Beyoncé in a new direction. He further wrote that the different elements of dance music present in the song makes it feel refreshing, before adding that "it might even suggest a more expansive, experimental side of the songstress on her follow-up". Talia Kraines of