BRITISH scholarship - or at least the presentation of that scholarship - has made some considerable advances in the last 60 years or so, ''The New Oxford Companion to Music'' being a worthy example. Reference works from the U.K. have for years been notorious (with me) as bastions of sometimes bloated opinion and jaundiced, cavalier judgments in the gratuitous, ''as you well know'' vein - as witness (alas) the most recent Britannica article on music.
This is one of several points taken up in editor Denis Arnold's preface to the ''New Companion,'' beginning with a sort of respectful apology for Percy Scholes's editing of the very narrow first ''Companion'' of 1938. The new one recognizes that the world of music has expanded profoundly since Scholes's time and has in parts been newly discovered, viz Africa, Asia, electronic music, third stream jazz, etc. The new edition is, indeed, a layman's reference book, and quite a commendable job it is, too. It seems one of the fairest, most comprehensive, yet most concise works of its kind and is in fact no more opinionated than a good many other works of even more compressed length. Arnold does advise in the preface that readers who need more facts should seek out other, more hefty encyclopedias such as the new 20-volume ''Grove's Dictionary of Music and Musicians.''
Pedantry, a waste of laymen's time, is nowhere paraded. Articles on scholarly topics such as ancient Greek music and organs and organ building are carried out in a distinctly unstuffy manner which does no disservice to their evident thoroughness. Both the readability and the soft-sell erudition of the present ''Companion'' make it a pleasure and complement well the flaking away of flamboyant British parochiality. A telling barometer of that latter was, for me, checking up the entry on Sir Edward Elgar, the composer who was ''all'' to musicians and music encyclopedists in England during the early part of this century. In number of pages, he outranked Verdi in the ''Grove's'' of 1927; in the work at hand, he receives a warm, fair several hundred words from Michael Kennedy, a sensitive, circumspect Elgarian, as well as a published biographer of him.
There are some exceptions, of course, and the entries of Gerald Abraham, author of the hefty one-volume ''Concise Oxford History of Music,'' stand out particularly for their brand of feebly resisted subjectivity - with his even more vividly held points of view than Scholes's. The ethnocentricity of his article ''History of Music'' is so pronounced that the case cries out for calling it ''History of Western Music.''
I have taken issue for some time now with Paul Griffiths, author of most of the entries on 20th-century music. Certain of his implied notions - predetermined attitudes about what is fit for discussion as 20th-century art music - and his, I think, willful insularity, do not make much long-range musical sense to me.
On balance, however, it is pleasing to see such sophistry and advocacy kept to the minimum in this new ''Oxford Companion.'' Its two volumes make quite an evenhanded, universal way station between shorter, one-volume lay reference works on music and the mammoth ''Grove's.'' On the whole, an attractive, desirable work.