HK Philharmonic Cultural Centre Concert Hall May 7 BEETHOVEN not only played but published two perfectly adequate cadenzas for his Fourth Concerto. One cannot say that they are perfect, and some pianists have tried to improve on them. But Sequeira Costa's two original cadenzas - presumably written by himself - simply lacked the organic cohesion of the original. His first-movement cadenza was long-winded Rachmaninoff, his third-movement cadenza as lugubrious as Tchaikovsky. When Andre Previn writes his own cadenzas for Mozart, they are historically legitimate, as Mozart rarely wrote his own. Musically, too, they have that organic unity which makes them part 18th Century, with little peeks into our own time. Costa, though, simply disturbed the Fourth, with veritable interferences into the original. Not that his playing was very impressive to begin with. The phrasing of the concerto was oddly awkward, the synchronisation with the orchestra in the last movement questionable at best. Last Friday, his artistry seemed to desert him. He was perhaps not inspired by the opening Fidelio Overture. It was adequate, but it was more bouncy than grand. The Swiss conductor Peter Maag showed a crafty intelligence in the crescendi, but the result had an unfair resemblance to Rossini. The second half of the concert, three short familiar pieces by Ravel, had to be better. Maag pounced on the Alborado del Gracioso for some Spanish fireworks. His Pavane had a beautiful sonority, and the final La Valse, a piece which can radiantly survive virtually anything, had an abundance of rip-roaring fervour.