Safe and commercially sound at any speed, the new albums by Kenny Loggins and Michael McDonald are likely to please old fans while leaving just about everyone else feeling a bit restless and bored.

For Loggins, who appears tonight and tomorrow night at Merriweather Post Pavilion, the problem isn't simply that he tends to oversing, though that quality alone can become unnerving; on his new album, "High Adventure" (Columbia TC 38127), he moves from the hell-raising clam-or of "Don't Fight It," a duet with Journey's Steve Perry, to the hushed romanticism of "Only a Miracle." The problem also has to do with the construction of the songs he writes.

Loggins has always been fond of using swelling, hook-laden choruses. This device not only has been responsible for some of his biggest hits, it has also provided both impetus and inspiration for Loggins' most exercised singing. But on either side of these choruses, Loggins lags; he doesn't have much to say, apart from the usual pop sentiments, and it's this deficiency that makes the most commercial songs on "High Adventure" -- "Heartlight" and "Swear Your Love" -- seem so one dimensional.

Enter Michael McDonald. McDonald has co-written with Loggins three of "High Adventure's" nine songs. While "Only a Miracle" is awash in strings, and doesn't clearly point to either Loggins or McDonald as its principal source, the other two songs are dominated by McDonald's feel for muted R&B textures.

The sound McDonald achieved with the Doobie Brothers -- through his use of the Fender Rhodes, synthesizer and his own whispery baritone -- is one of the most distinctive blends in contemporary rock. It also turns out to be a style that suits Loggins quite well, even to the point of tempering his singing at times. On such songs as "I Gotta Try," softened by McDonald's intimate harmonies, and the pulsating "Heart to Heart," Loggins may not be totally convincing, but he is comfortable, and is clearly better off following McDonald's lead than his own tired chorus on "High Adventure."

Michael McDonald's "If That's What It Takes" (Warner Bros. 23703-1) doesn't mark McDonald's departure from the soon-to-be-disbanded Doobie Brothers, so much as it documents the remarkable influence he had on the band. In the past five years, McDonald dominated so much of the Doobies' music that it's easy to lose sight of the fact that this, his first solo effort, isn't just another disc from the Doobies.

The principal difference, of course, is that McDonald dominates this album completely. Unlike Loggins, who is prone to sing optimistic and affirmative songs, McDonald tends to be more reflective, often preoccupied with torn and troubled relationships. It's this tendency that makes McDonald not only a more interesting and more provocative songwriter, but, in a sense, a better singer as well.

When he sings "Love Lies," for example, with its bitter chorus -- "Love lies, right to your face . . . Love lies, I know the word will never mean the same to me" -- his voice betrays a level of anguish that Loggins couldn't hope to achieve. Incidentally, in what is a rather unusual arrangement, both Loggins and McDonald have included different versions of their duet "I Gotta Try" on each of their albums; Loggins is heard singing lead on "High Adventure," while McDonald assumes that role on his recording.

Unfortunately, McDonald isn't above writing some mediocre songs, and for his backup band he's drawn from the usual assemblage of West Coast studio musicians, who again seem to be spreading themselves thin. Of all the familiar names, including Steve Gadd, Willie Weeks, Tom Scott, Jeff and Mike Porcaro, only guitarist Robben Ford offers a glimmer of personality with his brief solo on the title track.

So it's largely up to McDonald to keep this album afloat, and though he succeeds, for the most part, the success is rooted in a vocal and instrumental mix familiar to all Doobie fans. What's missing is any indication that the McDonald solo efforts are going to be any more consistent or colorful than what the Doobies were recording in their twilight years. If McDonald has any surprises in mind, he's not letting on. Not yet anyhow.

America, the duo that will be opening the Loggins concerts, may have shed the pretentious ambiguities that characterized its early lyrics, but it remains a lightweight, if largely inoffensive outfit. Intentionally or not, its new album, "View From the Ground" (Capitol ST 12209), briefly alludes to both the Beatles and the Bee Gees in a highly accessible fashion. Mostly, though, it's the commercialization of the folk-rock experiment that sets the mood for this breezy, innocuous album.