Dozens of famous musicians descended on Philadelphia during the week of the Democratic National Convention.  Demi Lovato, Alicia Keys, Paul Simon, Snoop Dogg, The Black Eyed Peas, Joe Walsh and Lenny Kravitz.  These aren’t the headlining acts of the next big summer music festival. They’re just a few of the many big artists performing on the convention stage and in concert halls around Philadelphia during the four-day Democratic National Convention.  Inside the Wells Fargo Center, elaborate performances and musical interludes have been woven into the prime-time schedule. Mr. Simon sang “Bridge Over Troubled Water” in the lead-up to Senator Bernie Sanders’s address on Monday night, and Lenny Kravitz sang “Let Love Rule” before Senator Tim Kaine and President Obama took the stage on Wednesday.  “They’re so deeply interested in bringing artists and entertainers together to conventions and political events because they’ve come to realize over time that they need to get the people that the people in this country are listening to,” said Jon Rubin, the chairman of Rock the Vote. “There’s a lot of things to listen to other than politicians that are a lot more compelling.”  Mr. Rubin’s group was one of many that organized and hosted concerts around the city this week to capitalize on the focus on the election and highlight issues, while providing a party as well.  “If you’re voting this year, put your cellphone or your lighter in the air,” shouted Dre Sinatra, a D.J. who backs the artist Ty Dolla Sign, at the Rock the Vote show on Wednesday night at the Fillmore. “We came here for something positive, right?”  The event also featured a performance by the Black Eyed Peas, whose set stretched into the early morning on Thursday. HeadCount, an organization devoted to signing people up to vote, also hosted a concert this week, with Grace Potter playing at the Electric Factory until last call.  During the Democratic convention, Rock the Vote has hosted an exhibit of art addressing social and political themes. Nick Corasaniti captured the scene on The New York Times’s Snapchat account.  “There are so many issues that entertainers, artists, activists, we’re all fighting for,” said Luis Calderin, the vice president for marketing and creative at Rock the Vote, “that the lines of an activist versus a musician are kind of gone. You look at someone like Beyoncé, and she is as much of a member of Black Lives Matter as Erica Garner.”  At the convention on Monday, Ms. Lovato addressed mental health issues before singing her hit “Confident.” Ms. Keys spoke about gun violence before serenading the audience with “Superwoman.” And Andra Day sang “Rise Up” after speeches by the Mothers of the Movement, a group of black women who have lost children in clashes with the police or in gun violence.  “Until we deal with gun violence in this country, we can’t claim ‘home of the brave,’” Ms. Keys proclaimed, vamping softly on piano chords before diving into the opening lyrics of “Superwoman.”  How we provided real-time analysis of the final night of the Democratic National Convention, featuring Chelsea and Hillary Clinton.  Not all convention guests, delegates and local residents can get tickets for every show; some events are open only to a specific guest list, as a thank you for supporting an industry or cause — and to encourage further engagement.  On Monday night, Joe Walsh and Jason Isbell ripped through solos for those invited to an event hosted by the Distilled Spirits Council. Nelly and D.J. Jazzy Jeff performed at the Recording Industry Association of America concert. And on Thursday, Snoop Dogg is to play at a concert hosted by Priorities USA and other groups supporting Hillary Clinton. Lady Gaga and Mr. Kravitz will play a show across the river in Camden, N.J., for delegates and invited guests.  The concerts may have all centered on one side of the political aisle, but many artists and organizers also see their performances as a buffer and a salve to the growing polarization in the country.  “Music is the universal language, it definitely brings people together,” said Aloe Blacc, a singer who gave multiple performances throughout the week. “Music is kind of the last playground. If you think of how raceless and classless a playground is, how children just play together in a sandbox without any kind of sense of difference, that’s what music is. It’s the adult’s last playground.”
As major artists performed on stage at the Democratic convention, political groups around Philadelphia were using concerts to draw attention — and provide a party.