Over the last three years, ODESZA‘s The Last Goodbye tour has spanned 54 shows at 48 venues throughout North America, including headlining sets at festivals like Governors Ball and Bonnaroo.

Tomorrow marks the beginning of its end. From July 4-6, ODESZA will play the three finale shows of The Last Goodbye run at The Gorge Amphitheatre, the iconic venue roughly 150 miles southeast from the duo’s hometown of Seattle. Sixty-six thousand fans are expected over the three nights, and if things go according to plan, almost all of them will pass through an on-site installation the act has created as a tangible, extraordinary and — this time — truly final goodbye.

Called “Echoes,” the installation comprises six 30-foot towers, 120 LED screens and loads of cutting-edge tech that will involve projection mapping and, naturally, sound. Made of brushed aluminum so the installation reflects sunlight by day, after dark, “Echoes” comes to life with video imagery incorporating brand-new visual content from the duo, the epic three-year tour and which is also, says the project’s head of creative Steve Bramucci, “in part inspired by the fans.”

This eight-minute video loop will be synced with sound mixed by ODESZA’s Harrison Mills and Clayton Knight. Known for the meticulous attention to detail they bring to their music and all elements of the ODESZA universe, they have been heavily involved in the design and execution of “Echoes.”

Their 10-minute soundscape was built from gentle ambient music mixed with voice notes that fans left for the pair about what the Last Goodbye era has meant to them, with people offering comments reflecting on things like how they never felt comfortable dancing in public until seeing the show; how the music helped them deal with the loss of parents, grandparents, best friends and relationships; how attending shows expanded their friend group; and how this chapter of ODESZA has brought joy to their lives.

It’s a soundtrack with the power to make one tear up while listening to it at their office desk, and it’s thus likely to make a strong emotional impact when fans experience it at The Gorge. (For those who can’t attend, the final show on July 6 will be livestreamed on Veeps.)

The project is designed “to be experienced in the ramping-up period before a show or ramping down after a show,” says Bramucci, “but you can tell that ODESZA is thinking people are going to sit in here for a few minutes. They’re not just going to race through, take a couple Instagrams and bounce.” Given crowd flow at The Gorge, Bramucci expects “97 to 98%” of attendees will pass through “Echoes.” (Another 3% will enter through the VIP area that doesn’t lead past the installation.)

The hope is that fans will indeed spend some time with a project that a global team has dedicated the last two months to creating. “Echoes” takes influence from a design originally built in Russia by Russian creative studio Setup, with a second creative studio, The Vessel, expanding on that design and project-managing “Echoes” in the States. The Vessel’s operator and co-founder, Jenny Feterovich, serves as creative director for the installation.

Meanwhile, Bramucci’s team at Uproxx was tasked with user experience, coordination and storytelling around the project, with a host of other companies involved with audio visual and scenic building. A 30-person crew has been on site since June 30, working around the clock to get “Echoes” up and functioning by the time doors open tomorrow at 5 p.m.

This challenge has been compounded by the logistics of working at The Gorge. “It’s literally in the middle of nowhere,” says Feterovich. “We have to truck everything that’s going there, and there is no room for error because you can’t run back to an office that’s three hours away to go get something. Preparation here is of utmost importance.”

The other major challenge is the weather. The build teams are preparing for possible high winds and assured heat, with temperatures during the build in the mid-’80s and temperatures on show days forecast to hit the ’90s. Saturday is expected to reach 100 degrees.

“Echoes” was designed on PCs equipped with Snapdragon, a microchip from Qualcomm that uses predictive artificial intelligence to anticipate a user’s movements in order to shut down and reignite programs and preserve battery life. On site, Snapdragon-powered PCs will be used to projection-map, troubleshoot and modify designs in real time, with the team also running visual and audio elements with Snapdragon PCs. Qualcomm subsidized the project, with the hard costs totaling in the high six figures.

“We’ve found that there are a lot of synergies between Snapdragon technology and this genre of music,” says Qualcomm CEO Don McGuire. “EDM artists embrace innovation and are open to experimenting with technology and new tools, making them great partners.”

Ultimately, though, all of the tech is intended to elicit an exclusively human response.

“If I see the face of even one fan who has a serious emotional connection to it, who’s like, ‘The aperture of my appreciation for music and what it means to connect to music has shifted because of this installation,’ then that’s the perfect win,” says Bramucci.