The lively acoustic of the lovely Stenton Parish Church, 23 miles east of Edinburgh, hosted the fourth of sixteen concerts in this year's Lammermuir Festival, the motto of which is Beautiful music – beautiful places. I have to confess to a carbon sin of the mind in being prepared to undertake the 46-mile car journey to hear 5 minutes of music by György Kurtág. Had his Signs, Games and Messages been the sole item in the concert I'd still have felt the car seat/church pew ratio to be worth it. However, excellent performances of string trios by Schubert and Mozart flanked these shimmering miniatures - played with electrifying insight by members of The Hebrides Ensemble: Zoë Beyers (violin); Catherine Marwood (viola) and William Conway (artistic director/cello).

The string chapter of Kurtág's multi-volume, open-ended opus dates from 1989-97 and contains eleven very short movements, of which the Hebrides Ensemble offered three. Virág az ember – Mijakónak consists of short, scalic phrases - several in the Lydian mode, which is often associated with happiness, or even euphoria. However, the still accompaniment, featuring artificial harmonics, combined with the fact that all three players are required to attach practice mutes, lends these melodies a frail, searching beauty. Perpetuum mobile, an altogether more ebullient affair, thrives on the tension between the ambivalent energy of its many open 5ths and the determined, directional pull of much more chromatic harmony. This, together with enthusiastically applied ricochet and pizzicato techniques ensured a short ride in a volatile machine. The drama in the closing, Ligatura Y, resided in the movement's refusal either to avoid or commit to a fixed tonality. Hovering, without pulse, between major and minor – and straying occasionally into bare 5ths or clusters – this uneasy backdrop underpinned some beautifully played, soaring cello melodies. Again, ghostly artificial harmonics featured, offset this time by some emphatic Bartók pizzicati. This wonderful performance prompted some e-detective work in an effort to track down the remainder of the volume and I would strongly recommend this work to any lovers of the Kodály, Bartók, Ligeti lineage.

Untimely death seems not to be the sole reason for unfinished compositions. Schubert had lived only 19 of his 31 short years when he laid aside his String Trio in Bb, D471 in 1816. With only 39 bars of the 2nd movement complete, the work is performed as a single-movement affair – the opening Allegro. While enjoying this beautifully phrased performance I was reminded - for reasons very different to those in the Kurtág - of the maxim "less is more". Fewer parts certainly affords each player increased space and exposure. However, Western-Europe's lasting love affair with four-part harmony also means that greater compositional skill is required to assemble a tightly-knit musical argument. The clarity of composition, playing and acoustic (the Holy Trinity of live performance) allowed me to spot, for example, an interesting detail; that the harmony frequently involved a central, driving viola part of detached, repeated notes, while the violin and cello played legato in surrounding parallel 6ths. This relatively wide interval lends melodies a yearning quality to which I felt the trio responded with touching sensitivity. Unlike some later Schubert works, where the major/minor polarity shifts a few degrees round the psychological wheel - replacing happy/sad with wistful/dejected - this trio evinces the youthful optimism one would wish for a 19-year old. Its sunny disposition was captured excellently by the Hebrides Ensemble and relayed to the snugly filled pews.

I though it a nice touch of programming that the first half's relatively short works allowed the audience to conserve the necessary audio attention for Mozart's substantial Divertimento in Eb K563 (1788). Compared to Schubert's Trio, this was a relatively late work, composed in the same year as his final three symphonies. Mozart, then 32, played viola at the work's premier. Only a character of conflict and contrast such as Mozart's would consider a rigorous 55-minute workout to be a diversion. This thoroughly captivating piece hinges on the kind of paradoxes natural to an expansive imagination tempered by an intuitive feeling for form and balance. The Minuets which surround the central Andante, for example, could not be less similar. The former is a minuet in denial, whose opening (and frequently returning) two bars of 3/4 would be perceived by most new listeners as three bars of 2/4. Contrastingly, it's mirror image - an über-minuet – leans, in the Trio section, almost in the direction of a Strauss waltz. Similarly, the theme of the Andante is extremely straight-forward – almost naïve. Yet, its variations are as sophisticated in treatment as they are quixotic in mood. By happy coincidence, this excellent performance was abetted by the frequently changing autumn afternoon light, refracted through the many stained glass windows - capturing what The Lammermuir Festival is all about.