Those who found the melancholy mood music of ...And Then Nothing Turned Itself Inside-Out dull will be advised to stay clear of Yo La Tengo’s latest, Summer Sun which treads the same conspicuously mellow territory with even less interest in approaching anything one could reasonably call rock music. If anything, Summer Sun is even more subdued than its predecessor, delving further into the semi-electronic soundscapes they have been slowly developing since signing with Matador.

For a band that once specialized into feedback-saturated sessions of guitar frenzy, it’s surprising to find them releasing an album on which virtually no guitar is played. When there is guitar, it’s either buried deep in the mix or so heavily treated with effects that it is indistinguishable from the synthesized textures that predominate (as in “Little Eyes” and “Don’t Have to Be Sad”, where the wah-wah-saturated guitar parts sound like a conversation between whales). In tracks like “Nothing But You and Me”, they continue to develop a painterly approach to songwriting, building songs by adding touches to a droning backdrop rather than using discrete verses and choruses with their own distinct chord structures.

The musical elements that comprise the songs—for most songs, invariably repetitive bass lines, loops from primitive drum machines, gentle piano tinklings, and muffled vocals—don’t ever cohere and blend. They are apparently arranged instead to remain distinct from each other, to show traces of the compositional process at work. The slow echo and the murky reverb give the album an underwater feel; or rather, it gives the impression you are listening to the music with some water caught in your ears. The care invested into fashioning these often precise and exacting songs is obvious, but the attention doesn’t pay any immediate dividends for listeners in the way of hooks. Only “Winter a Go-Go” offers a hummable melody, with an effective Farfisa lick accompanying it, to produce the album’s most satisfying song. “Tiny Birds”, with its quick pulse underlying a plaintive, descending gutiar figure, and its breakdown cribbed from “River Deep Mountain High”, works as well, perhaps offering a preview of what one can expect on bassist James McNew’s upcoming Dump release.

In general, Summer Sun seems a very complacent album, reprising the styles that seemed like compelling departures on previous albums. “How to Make A Baby Elephant Float” and “Season of the Shark” reprise the mall organ approach of I Can Hear The Heart Beating As One‘s “Center of Gravity”. “Today is the Day” seems like an optimistic companion to Nothing‘s “Tears Are in Your Eyes”. While “Let’s Be Still” revisits the instrumental drone territory exhausted on “Night Falls in Hoboken”, only with the addition of some arbitrary, untethered sax wailing, and Herbert Laws-style flute piping. “Moonrock Mambo” develops some of their unfortunate faux-funk leanings, featuring Ira Kaplan doing some rap vocals that recall Lou Reed’s disastrous efforts on the misbegotten Mistrial album. “Georgia vs. Yo La Tengo”, an instrumental effort in the same vein, is more successful, but it never transcends the level of interest generated by the average hip-hop sound collage.

It’s tempting to call the evolution in their sound a “maturation”—if maturity is defined as resignation, as surrender, as an acquiescence to established norms, then Yo La Tengo’s music can be properly called mature. Perhaps it’s best described as aural Valium, easing one’s acclimation into the humiliating demands made upon us by adult life. These songs are unlikely to distract anyone from their lattes at a coffee shop, or pre-empt any desultory conversation during yuppie meal times. This music cries out to be ignored, it begs to be background music, it defies you to pay direct attention to it for any substantial stretch of time. It’s the sort of album that is liable to lull you to sleep on the subway so that you miss your stop. But at the same time, it would be wrong to dismiss the album on these grounds: Summer Sun has an undeniable subliminal effect, establishing its wistful end-of-summer mood of ruminative nostalgia in listeners even if it’s April, and even if there’s nothing in their past they were particularly pining for. Even if one has dozed off somewhere in the middle of the album, by the time one wakes up to hear Georgia Hubley sing a gentle cover of Big Star’s “Take Care”, one is likely to feel inexplicably moved, as if one had lost something she didn’t know she had. Such is the subtlety of the album that it leaves no impression while it’s playing, but a profound one when it’s finished.