One could do worse than greet the new year with Beethoven's Ninth Symphony. Its final movement is an ode to brotherhood, and we all could do with a little of that these days. Clearly Lyn McLain believes this. For some years now, he has gathered together his D.C. Youth Orchestra members and as many of the orchestra's alumni and teaching associates as are in the area for the holidays, for a gala performance of this gigantic work.

Yesterday they all came together in the Kennedy Center Concert Hall, a large orchestra, a chorus billed as the "D.C. Youth Chorale Festival Chorus" that looked decidedly middle-aged but sang with the enthusiasm of youth, and a quartet of well-known soloists, soprano Wilma Shakesnider, mezzo Alteouise DeVaughn, tenor Alburtt Rhodes and baritone Ben Holt.

The D.C. Youth Orchestra is one of this city's ornaments. It sponsors a huge program of instrumental instruction and graded ensemble experience for young people throughout this city, and the large number of its alumni who have moved on to conservatories and to jobs as professional musicians attests to the excellence of the training.

The fine violin sound that characterized yesterday's performance was also a testimony to the program. Particularly in the adagio third movement, the broad and rich violin tone painted Beethoven's long lines with beauty and a sense of phrasing.

The performance itself was credible, if flawed. The large structure of the work was evident and there was a sense that much of Beethoven's intent was understood. The major problems were rhythmic ones. Sections of the orchestra seemed to have trouble hearing one another and McLain himself seemed reluctant to impose his rhythmic will on his large forces. There were moments, in fact, when it seemed that he and the whole orchestra might be gobbled up entirely by retards that threatened to bring everything to a standstill.

The soloists, several of whom have appeared here brilliantly in the past, were not at their best, and the chorus, which had a big sound, lacked finesse.