It’s in the nature of experimental music that there should be hits and misses: if it was all totally successful, all the time, then it wouldn’t be much of an experiment. But without wishing to doubt Apartment House’s credentials as leading performers of experimental music, their Wigmore Hall debut on Saturday evening was more or less all excellent.

Anton Lukoszevieze, cellist and founder of the group, wrote in the programme that the pieces defined “an Apartment House ‘aesthetic’” – this was clear from the off. Laurence Crane’s Sparling 2000, written for the group’s clarinettist, Andrew Sparling, is calmness through and through. An incredibly simple two-note phrase from the clarinet – a shortish note and then a very long one – repeats many times with gently changing rhythms. Underneath this, a string quartet plays soft, diatonic chords with the occasional biting dissonance. It’s like Arvo Pärt for its gentle atmosphere, and the simplicity of its materials – but there’s a touch of originality in this music’s assembly that I don’t hear in the Estonian’s music.

Much of Christopher Fox’s Memento was somewhat less calm, but the placidity of the piano quartet’s performance made sense of the enigmatic, Webernesque ending to this piece which begins with busier music, reminiscent (as Lukoszevieze wrote in his note) of Brahms and Ives. Fox’s second work on the bill, BLANK, was totally different, a slow study in small differences in intonation with a sombre, meditative air. It was preceded by Lithuanian composer Rytis Mažulis’ Canon mensurabilis, likewise involving alternative tunings, but contrastingly frenetic and dense, with Philip Thomas providing a persistent pulse on the piano with repeating two-note chords.

While a majority of the works performed were by Europeans, the one American piece on the bill made a strong impression. Peter Garland’s piano quartet Where beautiful feathers abound is – like a number of the pieces here, actually – strikingly diatonic, and its homophonic texture bubbles brightly. Perkier outer sections conceal an almost impressionistic central section full of slow, held chords, preceded by a long, deep silence. Mathias Spahlinger’s 128 erfüllte augenblicke (“128 Fulfilled Moments”) is also a work defined by its use of silence – each of the titular moments (not all 128 of which need be performed) is separated by a long pause. Apartment House also did this piece a couple of months back, but given how different each performance of it is, it was a treat to hear it again – even if the stifled atmosphere of Kings Place’s Hall Two made for a more intimate, intense rendition. Mezzo-soprano Lore Lixenberg appeared only in this piece, which felt like a missed opportunity, but it was an impeccable performance nonetheless.

A corollary of Apartment House’s apparently quite serious attitude on stage is that it becomes extra funny when the scores require them to do daft things. Both halves of the concert ended with slightly comic pieces: Amnon Wolman’s Dead End is for solo clarinet and a battery of toy trucks and cars which whir and buzz around the stage; three extra members of Apartment House sat around soloist Andrew Sparling to ensure that the toys never veered off the platform or into a piano leg. Aurally, it was like listening in on a clarinettist’s session in a small room with an air conditioning machine – but overall, it was oddly compelling.

And George Mačiūnas’ In Memoriam to Adriano Olivetti, a piece from the 1960s Fluxus movement, has the performers doing all sorts of bizarre gestures and actions and playing with strange props galore. Philip Thomas seemed to have had first dibs on props, with a nice bouquet of flowers and a very big flag, both of which he manipulated to great effect. With laughter from the audience, this was the perfect end to the evening. The only thing the concert lacked was a première: the programme, impeccably compiled though it was, perhaps lacked an edge of risk – of experimentation, even.