A hefty week of Bach in Madeira

This Portuguese island off the coast of Morocco, measuring some 13 miles by 33 miles, seems a highly improbable place for a Bach festival.

Yet every year in June, downtown Funchal - the main city on the island - is festooned with cheery yellow flags, bearing the words ''Madeira Bach Festival'' and a portrait of the composer. The generally slack tourist season picks up with vacationers and patrons of the arts. And for a hefty week the centrally located 15th century Cathedral Se resonates with Bach, an army of his contemporaries, and a few composers from later times.

This past year the list of artists included flutists Jean-Pierre Rampal, Jeanne Baxstresser, and Julius Baker; organist-harpsichordist Anthony Newman; trumpeter Edward Carroll; conductor Gerard Schwarz; cellist Wolfgang Laufer; the Orlando Quartet; the Utrechts Symphonie Orkest (from which the Orlando Quartet comes); the RIAS-Berlin Chamber Choir; a number of instrumentalists that make up the Madeira Bach Ensemble; and Elly Ameling, to mention just the most prominent names, all under the guidance of Yuval Waldman, music director and violinist.

Madeira is an enchanting island with a dramatic topography, superb vistas, delightful villages, historic buildings galore, friendly, helpful people - many of whom speak English, French, or both, as well as their native Portuguese. There is almost the danger that music on this little haven - on the same parallel as Marrakech - could be anticlimactic. Hearing Bach and his contemporaries in a cathedral very similar in size and mood to the Leipzig Thomaskirche, which he called his musical home for the last years of his life, is so beguiling that even if it were indifferently performed, the novelty of the context would make one forget, or at least overlook, many shortcomings.

This festival is very young still - a mere three seasons old, including the one just past. There is tremendous room for progress - which is not to say that lovely things did not occur throughout the seven-day festival. The concluding concert was devoted to Bach's astringent ''St. John'' Passion, featuring the Berlin-based radio choir, the Utrecht orchestra, and soloists under the direction of Uwe Gronostay.

The ''St. John'' Passion relies very heavily on the Bible text, with long selections given to the Evangelist - the tenor narrator of Bach's passions. The ''St. Matthew'' (also by Bach), on the other hand, has many large choruses and lots of arias that enhance the mood. Thus the Evangelist is crucial to the success of the performance, and in Peter Maus, the performance could boast an Evangelist of international caliber (though, curiously, less accomplished in the tenor solo arias).

Unfortunately, the rest of the soloists left a good deal to be desired, although it hardly mattered. Maestro Gronostay clearly understands the message and the medium, and his support and use of the chorus gave the performance a foundation of authority and conviction that the chamber choir enhanced at every opportunity.

The preceding evening the Utrecht players had been under the direction of Mr. Schwarz, the former trumpeter now conducting full time. The band is not of the highest quality, and in choosing the overperformed Mozart G-minor symphony, No. 40 (with all the repeats), Mr. Schwarz placed himself in the unenviable and unnecessary position of being compared with any number of other conductors of the work most listeners would have encountered in the none-too-distant past.

But his conducting in the Haydn C major Cello Concerto, with Mr. Laufer as trumpet soloist, was alert, sensitive, and supportive. Mr. Laufer revealed himself as a soloist of the first rank.

A Bach trumpet concerto featured the virtually omnipresent (and almost always appreciated) Mr. Carroll, whose lip, by this time, proved slightly less reliable than in the opening-night performance of the Bach Brandenburg Concerto No. 2. And in a splendid display of brass-and-organ music, Mr. Carroll and his New York Trumpet Ensemble shone in a variety of literature, with Mr. Newman the soloist-accompanist. Newman has always favored technical pyrotechnics, which is not to all tastes, since it tends to submerge musical values in digital prowess.

Mr. Newman was also on view as a conductor of the Utrecht at the finals of the flute competition held in conjunction with the festival. And finally, the composer was heard in the flute competition piece, and a new work to dedicate the new organ in the cathedral. That piece was about 12 minutes of this and that - mostly from the French romantic school of organ literature - that never quite fell together.

Miss Ameling sang enchantingly in the Bach Cantata No. 209, the highlight of an uneven evening, one of two Mr. Waldman led. He proved a more interesting violinist (in Vivaldi's ''Four Seasons'') than conductor. And his sense of programming throughout the festival relied on concert favorites - the Brandenburgs, Mozart's 40th, the Haydn ''Drumroll'' symphony, Vivaldi's ''Four Seasons,'' etc., etc.

Considering how much repertoire there is to choose from, it seems a shame so little variety was offered. And when an Orlando quartet is on hand, it seems strange to give the serious chamber music to an ad hoc group within the Madeira Ensemble.

Joel Corcos Levy is the man who discovered Madeira musically some 10 years ago and decided that it could be a unique place for a festival. Many of the people currently used as the festival regulars are good friends or people he admires deeply. Unfortunately, they do not necessarily come together as a memorable ensemble or as soloists or chamber players.

The best of this just-completed festival is obvious. Rampal, Ameling, and Baker are the sort of musical luminaries that draw people. The question is, in the seven days the festivalgoers spend in the Cathedral Se, do they hear enough high-quality music to return year after year?

This year there were disappointed patrons as well as elated ones. Next year, the lineup is dramatically stronger. Mr. Levy knows that improvement is a constant necessity in a festival, no matter how well known it becomes or how high the quality. Since his model (loosely speaking) is the Casals Festival as it started out in Prades, and the early days in San Juan, Mr. Levy has a stiff set of standards to emulate.

Nothing I heard in the seven nights was actually poor. Rather, it offered no profile, no distinction that would set it aside from, say, a regular outing at any number of local chamber groups around the United States. When the Madeira Bach Festival finds its profile, it will be something not only unique, but memorable and in demand. I look forward to watching it evolve.