There are two ways of looking at the current state of the Festival of British Youth Orchestras. One is to applaud the liberty that the organiser, the National Association of Youth Orchestras, takes with the term orchestra. It covers everything from a full symphony orchestra to a recorder ensemble, with brass bands, jazz groups and fiddlers in between, which gives the festival its diversity.

On the other hand, such variety means fewer symphony orchestras are appearing and this has implications for Britain’s many excellent youth orchestras, who are finding that there are fewer and fewer opportunities to parade their talents outside their home cities. The inclusion of a festival of youth choirs in this year’s programme only adds to the problem.

Almost two decades ago, the International Festival of Youth Orchestras went down a similar path of diversification, with fewer orchestras and more choirs, dance groups and theatre companies. It is now a multicultural arts event called the Aberdeen International Youth Festival.

One thing about the Festival of British Youth Orchestras hasn’t changed: it rarely saves the best until last. For years, the opening concert has been the epitome of thoroughbred music-making, though it may not have seemed that way in the first piece played by the Youth Orchestra of Andalucia in the concert hall at the Royal Scottish Academy of Music and Drama in Glasgow.

Pianist Javier Perianes’s interpretation of Mozart’s Piano Concerto No 21 was too heavy handed to be convincing as Mozart. There was eagerness and momentum, a credible sense of drama, but the mixture of bombast and poetry in the Andante was too much and the phrasing didn’t have the classical grace it should have had.

Shostakovich’s Second Piano Concerto was a wiser choice, though it came about by chance. Jose Z rate’s Alonso de Quijada was unable to be performed because of technical reasons, so the Shostakovich was substituted.

Though one could question the wisdom of programming two piano concertos side by side, in the Shostakovich piece Perianes was in his element. His playing had the required youthful wit and energy but was also mature enough to bring out the music’s duplicity.

Holst’s The Planets showed the orchestra functioning as a well-blended and cohesive unit. There was an instinctive rhythmical flux in the playing, power as well as definition in the tuttis and a lyrical sweep to the smallest of melodies.

None of those qualities were present in the lunchtime concert given the next day by chamber groups drawn from the Cambridgeshire and Peterborough Youth Orchestra. This was an ill-conceived venture that would have worked better had the bitty programme been cut by half and taken into shopping centres to raise the awareness of the festival going on in Glasgow as well as Edinburgh.

There was a good sense of movement and a warm tone in Mozart’s Divertimento in E flat; a clarinet piece by Mendelssohn was jolly and nicely paced and the performance of Elgar’s Serenade for Strings caught some of the emotional sweep of the music. But intonation was shaky at best and the performances were desperately underprepared.

In the performance given a few days later by the North Ayrshire RSAMD String Orchestra, Saint-Sa ns’s Danse Macabre had more dissonances than the composer intended. The cheerier the music, the better it played. Elgar’s Easy Pieces are nothing to write home about and one could hear colossal boredom in the playing. In the trickier, fun-filled Toy Symphony by Mozart the phrases were nicely shaped and concentrated effort went into the performance. A Vivaldi violin concerto had crisp strong rhythms and the soloist, Alisdair Gilmour, had clearly thought about how to shape the music.

The National Association of Youth Orchestras was given pound;40,000 by the Scottish Arts Council to include a festival of youth choirs in this year’s festival. The Glasgow Youth Choir started a weekend of Scottish choirs in the Glasgow leg of the event. The senior section opened with a clean cut rendition of the thumping gospel number “Oh Happy Day” and the concert continued with performances that had restraint, clarity and a beautiful control of dynamics. The junior chorus produced a bright, ringing sound and sung everything with the sort of crisp enunciation that Miss Jean Brodie would have died for.

The final week, next week, reflects the diversity of the current festival.

Fife Youth Orchestra is playing The Beatles and Brahms; there is a concert by Midlothian Classical Guitars; the West of Scotland Schools Concert Band returns under the excellent Nigel Boddice and the Royal High School Choir of Edinburgh is presenting a familiar classical choral selection that spans the ages. The Perth Youth Orchestra continues its tradition of having played in every festival and this year brings a programme full of delights.

Festival of British Youth Orchestras and Festival of Youth Choirs, until September 5, at the Central Hall, West Tollcross, Edinburgh, tel 0131 229 2921, and the Royal Scottish Academy of Music and Drama, Glasgow, tel 0141 332 5057 www.nayo.org.uk