Everything about The Polyphonic Spree is big. The band is big. The sound is big. Its overwhelming positivity is big. The lull between the band’s previous record and its most recent — six years — was big.

Biggest of all is the band’s ambition: The Spree is the size of five bands, with expenses so crushing that frontman Tim DeLaughter and his wife have mortgaged their house twice. The group recorded its newest album without a label. Instead, it used Kickstarter to fund “Yes, It’s True,” out Aug. 6.

On Saturday, 18 be-robed members of The Spree (including five founders) will pile into Sixth and I Synagogue and play a slew of instruments — including guitars, French horns and theremins — presuming there’s room for all of them.

On the band-or-cult debate
“Some of it was sloppy journalism,” says DeLaughter, sighing. “All of a sudden, the band is this cult.” The robes were meant to present The Spree as a unit. “We got a lot of press because of the way we looked,” he says.

On touring with 18 players
The band is smaller than usual at the moment. Regardless, it requires some “Magic School Bus”-style travel. The tour bus sleeps 27 — and it’s sleeping-room only; no lounges, no recreation areas. DeLaughter says it’s better than previous buses, which were so cramped some members quit the band.

On the size of The Spree
The issue of the band not fitting into venues has “always been an issue,” DeLaughter says. He recalls a gig at The Barfly in London, which holds about 120 people. “We were having to use tables and chairs to make the stage four times its size using objects around the club.”

On ‘Yes, It’s True’
Over the past several years, members of the band have regularly hung out to jam all night. Those jams served as the basis for the new record — filled with electronica, psychedelic sounds and the orchestral pop the band’s known for — which DeLaughter thinks might be The Spree’s most polished yet. “I usually can’t stand listening to my records,” he says. “But this thing, I listened to repeatedly for quite some time.”

Sixth and I Historic Synagogue, 600 I St. NW; Sat., 8 p.m., $20; 202-408-3100,(Gallery Place)