When Charles Mingus died on Jan. 5, 1979, the world of jazz, as the cliché goes, lost one of its giants. But unlike many of the other jazz greats who have passed on, the influence of Mingus is one which will be, or at least should be, felt by all lovers of modern music.

He was one of those musicians who made jazz accessible and even fun for listeners not normally attuned to its appreciative of jazz.

Because of that, just as Mingus was often categorized as a bassist, his status as a jazz musician, just as he was often pigeon-holed as violent or sensitive or both, so was he, of all things, at times a pop star, a dance-band entertainer in the otherwise off-times serious world of modern music.

Born in Arizona in 1922, the bassist played with traditionalists as well as Armstrong and Lionel Hampton and later associated himself with modernists like Charlie "Bird" Parker (saxophone) and Max Roach (drums).

He also led his own bands, teaching his musicians songs on the piano (he couldn't always put his ideas on written sheet music, and he would skim over the technical parts, always trusting his musicians could reinterpret Mingus' ideas in their own way), often coaching them as they played with shouts and moans that can be heard on the finished recordings.

Two albums have recently appeared that serve as a moving memorial to Mingus. Ironically, both were originally planned as a loving tribute only; that is, both were being prepared for production before Mingus' death.

One, "Nostalgia in Times Square," is a two-record set and a reissue of Mingus' two 1959 session albums and features a 10-man small-combo that combines six Mingus compositions with the popular female singer's vocals and lyrics.

Ms. Mitchell's "Mingus" serves as a bigger, more personal tribute to the man. Unfortunately, "bittersweet" is not the way Mingus should be remembered. Compared to some of Mingus' best work, which is punchy, lighthearted and broadly wild, parts of her album is dirge-like, serious and empty.

Most likely, the whole project was taken too seriously. The numbers are largely slow, Joni's vocals are over-recorded, by Ms. Mitchell's admission, three of four times. As a result, the music contains no improvisation, and improvisation was the heart of Mingus' success.

Melodies serve as the whole song, rather than as the base from which to launch solos. At the point where Mingus would cut loose and really begin a chase with his fellow instrumentalists - Mitchell is ready to end hers.

There are other problems with the arrangements. Mingus' music was full-bodied, with a constant "walking" bass line and horns that would play around and down the scale throughout each measure. Here, the horns occasionally play off of each other. The music on "Mingus" is incomprehensibly sparse.

Even with Weather Report's Jaco Pastorius on bass, the bass line is reduced to a few intermittent notes, played without regularity and with a dull, metallic sound. The other instruments follow suit, providing an odd, thin background to Mitchell's vocal numbers except the relatively upbeat "Dry Cleaner from Des Moines."

Ms. Mitchell's penchant for jazz, increasingly evident since "Miles of Aisles," seems to mesh well with many of Mingus' own ideas, although, again, much of the music is so bad that it's hard to tell.

Still, the singer's poetry tends to create a tone rather than define a situation, much like Mingus' own instrumentation.

And although some lyrics are embarrassing ("scratching the dry-cleaner do it/ Like Midas in a polyester suit"), others, such as "Goodbye Pork Pie Hat" (about saxophonist Lester Young) evoke a nice sort of sentimentality - by far the overriding tone of the album.

However, it's unlikely that Mingus would have cared for such mush. Despite Ms. Mitchell's liner notes and paintings, a plastic inner sleeve and some nostalgic recordings of Mingus and friends, it's doubtful that the album will win over many listeners.

The album is too "in" with the jazz scene to appeal to her broader-based listeners and too poor to capture the Mingus fans.

Now the good news. "Nostalgia in Times Square" is a completely different story. Taken from the CBS "Jazz at the Plaza" and "Mingus Dynasty," the new two-record set includes four previously unreleased recordings from the original sessions, including the brilliant "Pedal Point Blues," and many solos that were edited out of the original release.

The album stands as a testament as to why Mingus could not only command the respect of his peers but the attention of "lay" listeners as well.

Mingus' mixture of blues, be-bop and standard tunes does not stray far from standard improvisation in which an opening melody segues into various solos and then returns for the finish.

However, Mingus will often reintroduce the basic melody throughout the middle of the song, sometimes actually having it played behind one of the soloists, thus allowing the listener a chance to become lost during a piece.

Similarly, he will let one of his horn players improvise at the very beginning of a number as the other instruments carry the melody, thus striking a balance between Charlie Parker, who would often do away with an opening melody, and more conservative musicians.

Most of the pieces on the album, including "Jelly Roll," "Bird Calls" and "Slop," contain common chord sequences and standard chords, again allowing the untrained ear to follow the flow of the music (there are exceptions to this, including the no-less-remarkable tribute to Parker, "Gunslinging Bird").

What keeps the more experienced jazz aficionado from becoming bored are the brilliant solos by saxophonists Brooker Ervin and John Handy. Mingus and the others which are highlighted throughout the album.

Finally, each number reverberates with life. Mingus drives his musicians through the sessions, goading them on while their spontaneous solos crackle with electricity and vitality. The music has lost nothing in 20 years.

If Ms. Mitchell's album serves as a true death knell with its lackluster composition and arrangements, "Nostalgia in Times Square" brings notice that - as was often said of Charlie Parker after his death - Mingus Lives.