Some musical artists continually seek reinvention, while others revel in the niches they've carved out over the course of a career. Now nine albums into her solo career, Aimee Mann has a well-deserved reputation as a somewhat melancholy, always astute singer-songwriter. On her ninth and newest record, Mental Illness, the singer allowed herself to go exactly where she wanted. For Mann, that meant letting herself get as sad as she wanted and scaling back the instrumentation.

"It doesn't feel like new ground necessarily. It's just my favorite ground, and I gave myself permission to tread on that same ground as much as I felt like," Mann told The Week. From the start, she gave herself carte blanche to write the most depressing songs she could. The result is 11 songs full of character sketches and reminiscences of people with various mental illnesses. While such an album could seem quite exploitative, Mann uses enough detail and nuance that it never feels like a freak show.

"I just wrote what I felt like writing, and for me, that's always going to have some melancholy elements. To me, that's not depressing — melancholy, wistful, and pensive is not depressing — but I know to some people that translates as depressing. I felt like, nobody goes to me for a good-time party record, so it's useless to try to make myself into that in any way," Mann laughs. "There's plenty of other people who are making up-tempo pop records, and they don't need to get it from me, because my heart's not in that."

Mann's acoustic "fingerpicky" guitar and clear vocals are at the center of this new album, and Mann gives them ample space. Her new arrangement derived from the trio Mann often uses in live shows: "I played a lot of acoustic shows in a trio, just piano, bass, and acoustic guitar, and I found that that was my favorite way of playing live. I wanted to keep things stripped down when I made this record, and not worry about having anything that was particularly poppy or up-tempo or anything like that."

Mann admits it was temping to make an album with a bigger sound. But ultimately, the spare sound she created convinced her she was on the right path. "It's hard to tell yourself, 'No, it's fine with just acoustic guitar and vocals.' It seems frighteningly bare, but I knew that's the sound I wanted. I think there's a certain boldness that happens with just acoustic guitar and vocals. As it is, there's background vocals, there's percussion on a lot of songs, there's strings on a lot of songs, so it's not completely stripped down, but I wanted to try to give it that feeling of being very sparse as much as I could."

The background vocals are mostly hushed "ooohs," a sound she got from "very old-fashioned easy listening." Mann attributes the fingerpicky guitar sound to '70s influences, citing Loggins' and Messina's "Danny's Song" as an influence. But contemporary singer-songwriter-guitarists are clearly influences, too. Mann brings up her love for Elliott Smith, whose music helped encourage her to just make albums without thinking about the reception.

Part of the reason it's easy for Mann to make the music she likes is that she releases music on her own label, SuperEgo Records, and only has to answer to herself. It also helps that she has a clear-eyed view of the music business. Now that buying CDs is virtually obsolete, Mann has been forced to examine the way artists get paid. "Aside from vinyl, it's impossible to listen to music in any other way besides the streaming service. I would like to support artists and buy their thing, but even I have succumbed to the streaming service. I pay for it, but I know that it doesn't deliver much money to artists from my own experience." Mann adds that when artists try to predict audience desires, it usually backfires. "You can't anticipate what people like, anyway, you know? I think it cheapens it if you try to think, 'What would people want?", and then give it to them. I think what they want is an authentic expression of whatever the artist is going through at the time. They want authenticity, and it's certainly not authentic if you try to second-guess for a marketplace."

Without worrying so much about record sales, Mann feels freer to make exactly the music she wants to make. "I felt pretty relaxed about it. Part of my thinking is, if people aren't buying records anymore, then you really can do whatever you want. Why not? Why wouldn't you? So this is the kind of music I really do enjoy making. It's very fun for me. I like keeping things simple. I think there's a certain amount of power in that."

She's excited to take the new songs out on the road, too. And don't worry: Her concerts won't be total downers. "The show won't be completely slow and sad from beginning to end — but it will have a nice, chunky, slow and sad part in the middle."