Nathan Cross, who runs the totally excellent cassette (and now vinyl) jazz label Astral Spirits out of his Austin home, does not want to talk about the ska.


"Yes, I was in a ska band," he says during our chat. "I can’t believe I am saying that in public."


Look, it happens to the best of us. And there is no denying that, for a certain generation, ska was a gateway drug to the underground. First ska, then punk and indie rock, then whatever comes after that. Some get into electronic music, some go roots music.


And some, like Cross, get very into jazz and improvised music.


After doing time in increasingly abstract Austin rock bands, Cross has, for a little over five years now, run Astral Spirits, an outlet for his interest in documenting and releasing avant-garde jazz and improvised music, mostly on cassette.


His first tape, a 2013 trio date by the outfit Icepick (Nate Wooley on trumpet, popular avant-garde drummer Chris Corsano and bassist Ingebrigt Haker-Flaten) was released in fall 2014. Dozens of tapes have followed, to almost uniformly good notices from the jazz press.


Cross celebrated his fifth anniversary last fall with "Astral Ascending." Those wishing to examine the Astral Spirits catalog would do well to check out this three-hour, $10 digital download, which represents as strong a cross section of the label’s offerings as you could find.


But before he got into cool sounds that could be made with horns, the dude played guitar in a ska band. "Seven pieces," Cross says, "sometimes three or four horns. Look, growing up in Fort Wayne, Ind., it's kind of hard to get exposed to music. And so the fact that there was punk and the Mephiskapheles and Skankin’ Pickle records was important." We agree that ska can often provide a refuge for trombone players and move on.


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Cross’ world cracked open in Bloomington, Ind., in college. "Bloomington was amazing in the late 1990s and early 2000s," Cross says. "The Magnolia Electric Company guys were there. (The band) Impossible Shapes, (the record label) Secretly Canadian was just kind of getting pumped up."


The city was also a mere four hours (nothing to a college student) from Chicago, a city whose own jazz scene made a massive impact on Cross.


"A friend of mine in Bloomington got me to go to a concert with him to see a band I knew nothing about," Cross says. "It ended up being the Die Like a Dog trio (a powerhouse consisting of saxophonist Peter Brotzmann, drummer Hamid Drake and bassist William Parker).


"Absolutely blew my mind," Cross says. "We knew there was a lot more jazz in Chicago, so we would go up as often as we could. I always loved it, but I knew I wasn't a good enough musician to be part of that scene."


Cross got to Austin with the band Awesome Cool Dudes in 2003 and immediately started to go on tour with them, playing guitar and keys.


"And that kind of was what I did for the next five or six or seven years, more or less," Cross says. He and Cory Plump from Awesome Cool Dudes moved on to the larger, noisier When Dinosaurs Ruled the Earth, which eventually split into Spray Paint and Marriage, the latter of which Cross ended up in.


Marriage was even closer to the improvisational music Cross would eventually explore with Astral Spirits; the band also put out records on the recently shuttered Monofonus Press.


As everyone in Marriage got older and wanted to tour less, Cross started thinking about starting a label in 2013.


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"The name comes from a song by (avant-garde jazz musician) Joe McPhee," Cross says. It didn’t hurt that he started working production for the Pitchfork festival in Chicago, which is where he met a ton of musicians in the improv (music, not comedy) scene. And he always knew it was going to be a jazz and improvised music label.


"With improvised music and jazz," Cross says, "I know what I like. I trust my taste. I know how much something will sell. With rock and more popular styles, I don't know if I trust my judgment on rock records. I think that'd be like, ‘Man, this is a great rock record. I want to put that out.’ Would probably sell, like, a hundred copies. Free jazz was just the thing I loved."


For Cross, free jazz was more punk rock than punk rock. And the format appealed to him.


"I get a lot of people asking to review a release," Cross says, "And then I say it’s cassette-only. And then there's kind of silence for a while.


Frankly, he says, they are both aesthetically pleasing and cheap.


"I do think cassettes kind of have taken over that space of the 7-inch," Cross says. "Those things are expensive now. Used to be, if you just wanted to check a band out, you bought a 7-inch. Or a label put one out to test the waters, do an album if it took off. If a tape does well for me, maybe I will invest the time and money in an LP. It’s easy to make a little bit of money back on a tape, then do more. An LP you need an audience for."


And while he has documented Texas acts, Cross doesn’t think of Astral Spirits as a Texas outfit. "I live here, and I have put out stuff by Texas artists, but for me, jazz has always been about making connections and meeting people from different places," Cross says.


Nor should you look for Cross to dump Astral Spirits tapes onto Spotify anytime soon.


"I will put stuff on streaming services if an artist asks me to," Cross says. "That’s fine with me. But I am much more into the Bandcamp model," where users can stream the record a few times before having to pay for it. "It really has helped immensely with exposure. Something like Spotify, the odds are just stacked against me. I’m competing with pop acts."


These days, Cross is a busy man. His day job doing production with South by Southwest enables Astral Spirits to continue and Cross to play bass in USA/Mexico, a vibrant, scuzzy noise rock trio with Craig Clouse and Butthole Surfers drummer King Coffey.


"Austin is home; I’m kind of set here," Cross says. "I love being a fairly anonymous guy, putting out this music."