The iconic hard rock band arguably invented the arena rock spectacle, replete with synchronized pyrotechnics, elaborate stage sets and, of course, their signature face paint and glam rock demon costumes.

However, at some point — and we can debate all day long about exactly when this occurred — the pageantry became more important than the music.

And for the many fans that packed the Sleep Country Amphitheater on Friday night to see Kiss is concert, that’s something they readily accept and anticipate. Sure, hearing “Rock and Roll All Nite” was great, but hearing it while being showered in an unrelenting spray of confetti is apparently even better.

In that regard, everyone got what they wanted out of this deal: Kiss got their captive audience; the attendees got their sensory overload.

What suffers in this transaction though is the music. As exciting as it was to see singer and guitarist Paul Stanley ride a zipline to a small revolving stage in the middle of the crowd to perform the title track to the band’s 1977 album “Love Gun,” the audience appeared more concerned with taking a cellphone picture than anything he was playing or singing. And the nonstop fireworks and explosions, timed to coincide with big moments in the songs, were at least three times as loud as the band’s instruments. Making the mental adjustment to the radical changes in volume level was often taxing.

The quartet — Stanley, bassist and vocalist Gene Simmons, drummer Eric Singer, and guitarist (and former Portlander) Tommy Thayer — also rested on a tried and true set list of fist-pumping favorites. “Deuce,” “I Love It Loud,” “Lick It Up” and “Black Diamond” all made appearances, but the lack of deep cuts or curveballs left the more ardent Kiss enthusiasts feeling let down.

At a certain point, though, you just have to give yourself over to the experience because it is an experience more than it is a straight up rock show. There’s no earthly reason why Simmons should take a moment to spew fake blood out of his mouth, nor is there an logical point to the hydraulic platforms that lifted the band members 40 feet in the air as they played. However, it sure was fun to watch it as it happens.

By contrast, co-headliner Def Leppard‘s set seemed downright minimalist. There were small video screens flanking the stage and a larger display set up behind the band, but beyond that, it was just five men doing what they do best.

Like Kiss, though, the Sheffield, England-based glam metal outfit took no chances, sticking to the hits from their ’80s and ’90s heyday. And without the frills of a stage show like their tourmates’, the unfortunate flaws in their performance were far more apparent.

Age is catching up with the band. Singer Joe Elliott can’t hit the high notes that he once could with ease, forcing his bandmates to drown him out with harmonies. Drummer Rick Allen showed some obvious strain to keep up the demands of an hour-long set, even during his big midset solo.

Where the band looked and sounded the most comfortable was when they dipped back into the earliest part of their discography. Perhaps an offshoot of the return to basics sound that marked their last studio album (2008’s “Songs From The Sparkle Lounge”), the raw attack of tunes like “Let It Go” and the one-two set closing punch of “Rock of Ages” and “Photograph” had the most palpable impact.