About a year before his death, Prince believed he had discovered a new sound. When he recorded the single "Baltimore" – a response to the mysterious and controversial death of Freddie Gray while in police custody – he had a unique idea for its music. He had recorded a guitar solo that ran throughout the four-and-a-half–minute song but thought it could be approached differently. The musician sent it to orchestral arranger Michael Nelson, who plays trombone in the Hornheads and worked closely with Prince off and on in long stretches for the past 25 years. Most recently, Nelson did many of the arrangements on Prince's final album, HitnRun Phase Two.
"On 'Baltimore,' we basically orchestrated his guitar solo with strings and woodwinds and brass," the arranger tells Rolling Stone. Nelson (no relation to Prince Rogers Nelson) had earned the trust of the artist over the years and recorded the arrangement remotely. "When we finished that track and sent it to him, he sent me back a note with a link to the finished recording saying, 'As you can hear, we're onto something special.' He said, 'We're going to redefine the Minneapolis sound, and I'm going to need your pen to do it. So block off some time in the summer.'"
When Prince began working on the song in his own studio, he played around with the orchestration. He removed his guitar solo from the first part of the song, brought it in in the end and pulled back the horn arrangement. "At 2:28, you actually hear the guitar play with the strings into that string section which originally continued as the guitar solo," he says.
Prince also moved Nelson's work around in the song. "There's this string line at the very beginning of that song that's really interesting and it's not at all where we put it," he says with a laugh. "That's the type of thing he would do. It's like he shifted it by two-and-a-half beats, just something that made it completely different than what was intended. You'd never write it that way as an arranger, but you just go, 'Oh, my God.' It's really cool. He would make that adjustment and make it totally Prince. I tip my cap to the genius and I'm glad I was a part of it."
A fan of the process, Prince began sending Nelson songs that he wanted what the arranger calls "big orchestrations" on. Nelson estimates he worked on four or five songs with symphonic guitar solos for the artist, though some might have been intended for other artists. One was intended for a new 3rdEyeGirl record (its working title was "New 3rdEyeGirl String Session"), and guitarist Donna Grantis came to the studio where Nelson was recording. "It had a couple of different guitar solos, so we orchestrated around them," he says.
"The thing about his guitar solos is, as everything he did, it had a uniquely Prince take on it," he says. "They're quirky and they're melodic and they're interesting and they're just ripe for orchestrating. They're just so interesting."
"I don't know if it will ever come out but it's one of the most incredible things I ever worked on."
Nelson also recalls getting a pop song that featured another unidentified female singer. "It had this buildup to a great guitar solo," he recalls. "When he sent it, he wrote, 'There's a long build that I want tension for and then when the guitar solo happens, you know what happens next.'" Nelson laughs. "I don't know if it will ever come out but it's one of the most incredible things I ever worked on."
That song was titled "Pangaea," and Nelson recalls it was particularly challenging. "It was one of those where you got done with it, and go, 'Boy, I think he's going to really like this,'" he says. "And all I got back was a note in all capitals, '"PANGAEA" IS MAGNIFICENT.' That was it. I was like, 'Yeah, I'll get at least one more song.'" Nelson laughs.
"Besides the loss I feel personally now, I feel like my creative world has been gutted," he says. "These songs were big productions and they take a lot of people. We were doing 10 strings multiplied four times. And I was doing the horns, I was doing woodwinds and I was bringing in French horns and in one e-mail, he said, 'I want harp and timpani and bells and everything. Have fun.' What artist says that? And what artist can pay for that? What artist can support that?"
Nelson says Prince was always seeking a new sound and new creative input. On another track, "Shades of Umber," which he says had a "rock opera vibe," he put together a double-sized horn section more befitting of a jazz ensemble with 10 horns. It's a sound that Nelson says struck Prince in a big way. "I remember him saying one time – and this supports the fact that he was thinking bigger stuff – 'Someday I want you to come in here with 30 or 40 of your friends and just see what you can do,'" Nelson says with a big laugh. "I said, 'OK, great.' I think that's what happened with this orchestration stuff. That's essentially what it became."
"He just wanted kind of an Earth, Wind and Fire thing. We did horns and strings and it turned out great."
The last track they worked on together was this past January. "He just wanted kind of an Earth, Wind and Fire thing," Nelson says. "We did horns and strings and it turned out great. He sent a really nice note about how much airplay it was getting around the studio. I was like, 'This is gonna be such a wonderful process. What's gonna come of it is going to be really special.' And just like that it's gone. And I'm just stunned. I sit back going, 'That was it.' It was a moment in time. I have to appreciate what I had, but he just seemed unstoppable."
Now Nelson is just hopeful that the music makes it out to people. In the past five years, he estimates he worked on some 35 songs, though a fraction of the work came out. He says Brent Fischer, the son of Prince arranger Clare Fischer, estimates that for every one song Clare made with Prince, 25 are in the artist's vault. Moreover, Nelson says that some of the things he worked on for Prince were for other artists that Prince was working with. "We did a couple tracks for Rita Ora," he says. "I think one was for Eryn Allen Kane, who sang on 'Baltimore.' We did a song for Ledisi. And of course 3rdEyeGirl."
With the artist's estate is still being worked out, the fate of the music in Prince's fabled vault remains in flux. "I wouldn't be overly surprised if some old will pops up somewhere," he says, pointing to Prince's legal battle with Warner Bros. in the Nineties.
"There's so much music," he says. "I just can't even imagine. … God, I hope some of this comes out."Following Prince's death, Minneapolis threw a nonstop, citywide celebration to mourn and honor the musical legend. Watch here.