If you’ve got the radio blasting while you’re driving through Los Angeles, you’re guaranteed to hear Capital Cities’ “Safe and Sound” at least three times on three different stations between Venice and the Valley. This was the case long before the LA natives’ big label debut, “In a Tidal Wave of Mystery,” dropped via Capitol at the start of the summer and the fervor for its first single has grown at a tsunami pace since, taking on Top 40 radio and a handful of 2013 Best Of lists. Before the band’s co-headlining show Monday at the House of Blues with fellow Angelenos Fitz and the Tantrums, we caught up with singer Sebu Simonian as he was parked in a Walmart parking lot somewhere outside of Allentown, Pa., about reppin’ LA, going major label, and having a “That Thing You Do!” moment.

Q. I feel like I hear “Safe and Sound” everywhere now, and I don’t hate it one bit. What does it mean to be a representation of the LA music scene now that you’re becoming a household name?

A. To be honest, when we make music, we’re kind of in our own little bubble. The funny thing is, our association with other LA acts has been when we’re outside of LA, because we’ve had a chance to meet really cool LA-based bands on the road. We’ve been playing a lot of festivals that they’ve also been playing at, bands like Fitz and the Tantrums and AWOL Nation. It’s cool that we get a chance to actually meet them and become friends. I think LA’s a great, great city, because it’s diverse, both musically and culturally, and also with the landscape. I think that diversity is reflected in the music that comes out of there, and we’re happy to be a part of it.

Q. I know the record just came out in June, but we had an EP and some singles from you long before then. What was the biggest learning experience you had between those actual physical releases?

A. It was always a gradual process, so there wasn’t a significant change at any given point. We just always set out to write good songs that we liked, and the album was released pretty much when we felt like we had enough good material to call it an album. When we had about 12 songs that were pretty much completed, the timing was just right so that we could put out the album.

Q. What’s something you learned from “In a Tidal Wave of Mystery”?

A. Production-wise, what we learned making this album, is less is more. Try not to hide behind gimmicks and production tricks. Make sure that the most important focus is the songwriting and the melodies and the lyrics.

Q. What was something that surprised you when you left the world of indie and became a major recording artist with that big label affiliation?

A. The only thing that was unexpected, to be honest, was how busy we would be on the touring side of things. We set out to do our first US bus tour last summer or late spring — that was supposed to start off as a one-month thing and that ended up being two and a half months. After that, we quickly booked more shows, went to Asia, went to Europe, did another full-on bus tour. I’m surprised in a very positive way with how busy things could get. It’s great for us because it allows us to travel and see the world, which is obviously a wonderful privilege.

Q. Do you remember where you were when you heard “Safe and Sound” on the radio for the first time?

A. I didn’t actually hear the song on the radio but a friend of mine told me that Nic Harcourt of KCRW just played our song. I was at a friend’s house feeling really sick and under the weather that day, I had the flu or something, so my body was not in a good state. I got the shivers. I think I had a nervous breakdown. It was hardly due to the news but probably more because I was exhausted and sick [laughs].

Q. I rewatched “That Thing You Do!” and the scene where they hear their song on the radio for the first time really struck me. Obviously, the industry’s changed but I feel like that’s still a very exciting moment for a young artist. When was a moment when you were on tour and you had that kind of moment, where you realized that everyone was listening to your music and that they were coming out to see you?

A. Even that experience has been gradual for us. We’d been DIY for such a long time and we started playing shows from the very beginning, so every show that we played felt like an improvement on the last, be it our performance or the crowd numbers or their reactions. But of course, when you start playing [for] much larger numbers, especially at festivals, it’s definitely eye-opening. It’s validating. It feels like we’re doing something right and we’re enjoying every minute of it.