Late night television changed for the better when Jimmy Fallon — comedian, “Saturday Night Live” alumnus and former host of “Late Night” — became the sixth host of the institution known as “The Tonight Show” on Feb. 17.

But before that could happen, Fallon, The Roots and the writers and crew had to put on test shows. These performances look and sound just like the real show, but are only watched by the studio audience and are used to smooth out any wrinkles. This week, WSN was granted a look at the whole new studio, theme song and next generation of “The Tonight Show.”

Studio 6B, the home of most of Fallon’s “Late Night” and, more notably, the home of “The Tonight Show Starring Johnny Carson” before Carson’s move to California, has traded in its rough, urban atmosphere for a smoother, more immaculate ambience.

The refurbished walls are made of light, naturally golden wood that also lines the new bandstand for The Roots and matches Fallon’s desk. The new two-toned blue curtain drapes from the ceiling down to the shiny dark floor, contrasting nicely with the wood and the bronze shamrock where Fallon stands for his monologue.

Even the personnel got a minor makeover: The Roots have added a horn section, including trumpeter David Guy of Sharon Jones and the Dap Kings. As Steve Higgins introduced the show, the band played the new theme song, a bit slower and more playful than the tune featured on Fallon’s “Late Night.” This intro is a good match for the new opening sequence directed by Spike Lee that depicts Fallon walking through New York.

Fallon ran through his monologue and Thank You Notes as if for a real show, though perhaps taking more time to riff with Higgins, much to the audience’s delight. Next, Fallon introduced his guest John Oliver, who discussed his new HBO show “Last Week Tonight.”

For a few moments in the test show, Fallon showed characteristics similar to Carson’s. All that was missing was booze, a few cigarettes and Frank Sinatra. It all made sense right then and there — Fallon and this new studio have created the purest “Tonight Show” since Carson’s.

Fallon has brought the show back to New York in more ways than one. Using Spike Lee, having wooden skyscrapers and operating from Studio 6B in 30 Rockefeller Center brings a whole classic New York attitude that radiated from Carson and that has been lost since. Fallon has big shoes to fill, but his team, headed by SNL producer Lorne Michaels, could not be more ready.

For those who have their doubts regarding Fallon’s readiness, once they see him beaming in that studio with the wider camera angles, crisper lighting and bigger audience, those doubts will dissipate.

Behind all of the shine and prestige, Fallon’s friendly persona has not changed. He still ended the show by running through the audience, giving high fives and hugs. After a final wave goodbye, he went to his dressing room to keep working on Monday’s episode, the first of many for “The Tonight Show Starring Jimmy Fallon.”

A version of this article appeared in the Tuesday, Feb 18 print edition. Sean Hickey is a contributing writer. Email him at [email protected].