POP MUSIC : Learning to Deal With Smashing Success : From the recording studio to Lollapalooza, the pressure on Billy Corgan--especially the self-imposed kind--just never lets up.

For the first time in Lollapalooza’s four-year history, the headliner this summer hasn’t been upstaged by one of its support groups--a la Nine Inch Nails’ eclipsing of Jane’s Addiction in 1991.

In fact, the Smashing Pumpkins--who were bumped into the headline slot after Nirvana pulled out of the tour shortly before Kurt Cobain’s suicide--have far exceeded expectations.

But Billy Corgan, the soft-spoken leader of the Chicago quartet, has never been one to brag about the success of his band. Even after the group’s 1993 album, “Siamese Dream,� went platinum, the low-key singer and guitarist still talked often about his doubts and insecurities as a songwriter--and downplayed the importance of the Pumpkins altogether. (Virgin Records will release “Pisces Iscariot,� a collection of rare or previously unreleased Pumpkins material, on Oct. 4.)

As the tour wraps up with shows today and Monday at Cal State Dominguez Hills’ Velodrome, Corgan, 27, spoke about the effect of “Siamese Dream� and Lollapalooza on the band.

Question: What’s it like coming on at the end of a 10-hour Lollapalooza concert? Is it hard trying to energize the audience after such a long day?

Answer: Absolutely. We initially wanted to play the second-to-last slot, but it just worked out that we were headliners, so we had to adjust our thinking. But even though we’re the headliners, we know we’re not the main attraction.

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Q: What do you consider to be the main attraction?

A: The whole show overall. I don’t think we’ve (reached) the kind of status that would define the whole Lollapalooza thing. That’s why we didn’t want the last slot. You need more well-known songs to pull that off, where we only have two that people might know. It’s been daunting. I feel like we’ve had to fly by our wits.

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Q: From audience and press reactions, though, it seems you have been pulling it off.

A: Well, that’s the challenge. You just have to go on doing what you’re doing, even if it’s not gonna be easy--and do it in such a strong way that it doesn’t leave a lot of doubt.

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Q: Which band has impressed you the most on the tour?

A: To me the most impressive has been Nick Cave & the Bad Seeds because they’re so damn good under such terrible circumstances--3 o’clock in the afternoon . . . playing in front that whole empty-seats kind of thing. They really define greatness because they just refuse to suck. I’ve also enjoyed Flaming Lips (a second-stage band earlier in the tour)--and L7 have been good as usual.

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Q: What are some of the specific elements you look for when listening to other people’s music?

A: There’s plenty of good music out there, but a lot of it’s so bland and unoriginal, and it seems so uninspired. Like these days, I’m working harder and harder to find real inspiration. It’s like there’s so many Stone Temple Pilots that basically take what’s already been done and just do a decent job of it. As there’s a greater proliferation of grunge-era bands it’s harder and harder to find any original intent or point of view.

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Q: Last year, you talked a lot about the pressure and weighty expectations you felt in between your first album, “Gish,� and “Siamese Dream.� It really seemed to stress you out. Are those pressures still part of your life?

A: I feel more an artistic pressure than a commercial pressure. Not to sound snide, but I feel I could always make a record that could sell, but it’s not about that for me anymore. Back then, I felt this pressure that if we weren’t successful that we would just be passed over. I had a lot of my own personal insecurities involved there too. Can I write the three-minute pop song? It really seems trivial to me now after everything I’ve been through in the past year. I’m old enough now to just want to define myself artistically.

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Q: So what are some of those changes you are referring to that you experienced in the past year?

A: While doing the last album, I had to come to grips with a lot of things--the way the band interacted, my own feelings about myself and what I wanted out of my music. I just found I really want to pursue what I want artistically. I’m more comfortable in the role of enigmatic, difficult artist that makes good music than I am as the guy who writes three-minute pop songs that will change the world. It strengthened my intent, because I was kind of wishy-washy there for a while.

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Q: Lollapalooza ’94 will be over Monday. What is the first thing you are going to do when you get home?

A: I usually lay in bed for three days. That’s pretty much typical post-tour mode. I still have to do something musical though . . . so I’ll probably make tapes off my favorite albums. Then after that, I’ll slowly start picking up the guitar and start all over again. I plan to make a double CD after that.

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Q: What’s your relationship with the rest of the band like now? It was a little bumpy there for a while.

A: It’s all right. I just completely readjusted my thinking and kind of laid off them. I’ve stopped looking to everyone to help me get what my mind’s set on--in other words, sitting around waiting for other people to write songs and pull an album together. I just now accept that I’m gonna write every song. It’s no longer a me versus them. I just take it upon myself to accept most of the responsibilities and not be bitter or passive-aggressive. It’s not the situation I always want to be in, though.

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Q: What’s the ideal band situation, then?

A: Where I would just be the singer and the guitarist and wouldn’t have all these other responsibilities.

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Q: Can you realistically do that?

A: Well, that’s a question everyone asks, including me.

Vital Stats

Lollapalooza ’94

Main Stage acts: Smashing Pumpkins, Beastie Boys, George Clinton, Breeders, A Tribe Called Quest, Nick Cave & the Bad Seeds, L7, Green Day

Dates: Today and Monday, noon

Address: Cal State Dominguez Hills

1000 E. Victoria St., Carson

Tickets: Sold out