Non-Singing Voice: Done a little oddly. When the characters are singing on their own or in a small group, the voice actresses provide their own singing. Yet during concerts, the songs we hear seem to be straight from the singles and stage albums. Gets particularly jarring in episode 21, where Yuuko is supposed to be singing the last, solo line in Heavy Rotation but the voice sounds nothing her voice actress's singing voice that we hear twice in the episode.
The English dub is similiar, with songs being in English when the characters are singing in a casual situation, but switches to back to Japanese for the concert parts.
Real-Life Relative: In the English dub, the sisters Kanata and Sonata are played by real life sisters Juliet and Genevieve Simmons.