Jim James, the singer and leader of My Morning Jacket, tried to speak to the audience on Tuesday night at Webster Hall, but couldn't. When he tried, it sounded like 10 watery voices booming, out of sync, from 10 different places. The engineer hadn't turned off Mr. James's reverb.

My Morning Jacket wants to flood your emotions, the way music in a cathedral can, and Mr. James's voice, through all that reverb, conducts chills. Its primary position is singing-for-yourself, high and nasal, a little bit like Bob Dylan's "Nashville Skyline" vocal persona, or like the voice that the cellist and singer Arthur Russell used on his album "World of Echo." But he moves it outward, using a strong falsetto, pushing his inner world into yours.

The echo fixation has done My Morning Jacket right for six years, although one can see the end of that road on the horizon. It has already begun to address it: "Z," its new album, luxuriates less in the physics of the resonating chamber and more in the dry science of songcraft and arrangements; it's harder and leaner, with less acoustic guitar than before, and less reliance on an old notion of Southern rock.

This is a band long on good ideas and ways to sequence them. Tuesday night's show was above all well organized, with pockets of jamming opening up inside tight dimensions; there were serious shifts in mood, as if several bands were living inside one. "Run Thru," one of the set's longer songs, went at a crawl, with a biting guitar line doubling Mr. James's singing, and a big, spooky organ sound in the back: Pink Floyd, if you like. Then the band pivoted into tribal drumbeats in double time, as if taking cues from the stoner-rock band High on Fire.

"What a Wonderful Man," a new rave-up, did something similar. And "Off the Record" began with reggae, emphasizing the second and fourth beat, then started whomping down with equal force on the one and the three as Mr. James and the band's other guitarist, Carl Broemel, wove their lines together for a few minutes at a stretch, going quiet and then surging.

This band has the will to stretch songs and started to do it halfway through the set. But it didn't go far enough: one could imagine "Off the Record," as well as "It Beats 4 U," a new song with an unusual drum pattern, at twice their length. Mr. James is a wizard of momentum: as the songwriter and band leader and the guitarist with the more personal touch, these songs are his playgrounds. After having set the frequency of each song with his voice, he strikes with a guitar solo at exactly the peak moment, once the rhythm section has plied its medium-tempo groove for just long enough.

But for all that momentum, there was never enough release in pure sound. Tuesday's show, like others on this tour, was a 16-song retrospective when could it have been a 12-song feast of sound at the same length. Four or five times, the band went right to the brink, where you might have expected extra stretches of real collective improvising, or several extra minutes raking up textures, working over drones. Instead, the band economically completed the solos, then hustled the songs to an end, clamping them shut; it had the effect of leaving you peering down, feeling dizzy.