The sharpness of the piano's percussive attack creates treacherous problems for piano duos. The echoing clatter of notes and chords not struck exactly together is a major peril. And the temptation to compete, for each player to regard the other as a challenge over which their own part needs to be asserted, can make for a mean dynamic level that's too high, and which can quickly fatigue the ear.

Kathryn Stott and Noriko Ogawa are both pianists with successful solo careers and at their concert in Belfast's Waterfront Hall Studio on Tuesday, their relatively recent partnership revealed more the problems of piano duos than the rewards.

Japanese composer Hajime Okumura's Yatai-Bayashi of 1966, with its heavily-pounded rhythms and naive melodic directness, is rather like George Antheil's work of the 1920s, re-thought with touches of 1960s rebarbativeness.

It's easy to see why the players chose it as an arresting concert-opener. But the effect on Tuesday was rather like placing a chilli-rich dish at the start of a meal. The opening of Brahms's Haydn Variations ricocheted and floundered in its wake.

In the Brahms, as through most of the rest of the programme (Poulenc, Lutoslawski and Rachmaninov), the players' frequently poked-out cantabile presented, ugly, cutting lines. The tonal balances they chose tended to polarize into heavy top and bottom lines, with a hollow middle.

The effect was not ameliorated by the mix of instruments they were using: an un-lidded Yamaha with thin and penetrating middle and upper registers, and a brassy bass, with a mellower Steinway behind it. Nor was it much helped by the players' switching of instruments and roles. On the evidence of this recital, if you want to hear Stott or Ogawa, catch them when they're on their own rather than as a double act.

Harpist Cl∅ona Doris's "Music at Ten" recital at the Harty Room was, by contrast, easy on the ear and delicate, even Ian Wilson's In blue sea or sky, which Doris premiΦred last year, sounding among the lightest of this composer's works that I've heard for a long time.

There was nothing profound here, but a carefully chosen programme (Marcel Tournier, Sophia Corri Dussek and William Mathias, as well as Wilson) to provide a polished and graceful end to the evening.

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