For this concert Sigvards Kļava, chief conductor and artistic leader of the Latvian Radio Choir, worked as a guest conductor for the Dutch choir Capella Amsterdam. Modern and contemporary classical music play a significant, but not exclusive, role in the repertoires of both choirs. Daniel Reuss, artistic leader of Capella Amsterdam, chose Kļava to refresh the choir and its audience with pieces rarely ever performed in The Netherlands: some quite experimental, others distinctly Russian. Because of my particular interest in experimental music this is a review of the first half of the program, featuring modern classical music dating back no more than 40 years.

A strong wind kept blowing against me as I cautiously crossed the thin bridge leading to Amsterdam's most modern concert building, Muziekgebouw aan 't IJ. This sharply venue situated near Amsterdam's central waterfront (the IJ) was brought to life only in 2005. Its cubic heart, the concert hall, is spatially encompassed by the foyer (optionally serving as an art gallery), music lab for children, jazz stage, restaurant and café. As I entered the concert hall the greater part of the 500 seats around me filled up slowly. I noticed that my age of 28 made me one of the youngest attendees.

Knut Nystedt's Immortal Bach (1988) is a new arrangement of Bach's chorale Komm, süßer Tod, komm selge Ruh (1736). Nystedt adds complexity to Bach's piece by intertwining Komm, süßer Tod's three phrases. Several sections of the choir sing at different slow tempi, so that all phrases of the composition come to overlap and interact with each other. The result is an immensely layered cloud of voices. Many dissonant (roughly textured) moments slowly fade in and out, and from time to time a harmonic or quiet moment makes a break in the cloud. The curious, or genius, thing about this composition is that while it moves beyond Baroque harmonies it does not lose its sense of spirituality.

The men and women of Capella Amsterdam entered the hall and split up into three groups, one on the stage and two on the sides of the hall. This spatial positioning made the sound omnipresent, like the smell of incense in a church. The choir brought a post-heavenly sound to earth, with slightly haunting but perfectly executed (dis)harmonies drifting through the hall. Vocals, high and low, female and male, slowly entangled and disentangled. Tones could be prolonged endlessly as they were passed on from singer to singer. That didn't stop me, though, from having a few anxious moments, when I imagined the singers running out of breath. Hard onsets of the sung words were accentuated to break out of the drifting 'ambient' layer (written 10 years after Brian Eno's Ambient 1: Music for Airports), perhaps necessary in coordinating the timing between the choir sections. I didn't feel that these short bursts of vocal noises particularly added something to the piece, but they weren't disturbing either, and it was fun to hear them coming from different directions. The choir's impressive dynamic precision struck me as the piece became progressively fragile towards the ending. The acoustics of Muziekgebouw carried every subtle detail. It was incredible to experience the music so powerful on such a minimum volume. Bravo.

Next up were Alfred Schnittke's Three Sacred Hymns (1983-1984), polyphonic works hailing from the time that religious freedom was on its return to the Soviet Union. Schnittke was attracted to Christianity but could not decide which doctrine to follow. These doubts are expressed musically in Schnittke's fusion of Russian Znamenny chant, Catholic Gregorian chant, Jewish cantillation and Protestant chorales. I thought it sounded like Christian music that at times wanted to break out of its box. There was a little drama in the air, perhaps hinting towards the Romantic period. Capella Amsterdam was strong in all parts. I didn't develop a very strong opinion on the piece, but it's imaginable that it will grow on me. Apparently, some people prefer his work to that of Arvo Pärt…

Hillborg's Mouyayoum (1983-1985) celebrates the broad spectrum of sounds a mouth can make, without using a single word. Even 'Mouyayoum' has no meaning. It can be pronounced in a funny way though. The choir entranced me with an astronomical spectrum of voices, graciously morphing from one big chord to the next. Mouyayoum is all about harmonies, and the dynamic and textural contrasts within these harmonies. The piece surpasses Immortal Bach in terms of depth. It plays with the space between the vocal layers by moving voices between the background and foreground. A sense of mysticism or primitive spirituality is evoked as the short and powerful phrases in the foreground (humanity?) seem to call out to the densely layered background (eternity?). Mouyayoum is filled with subtle surprises; it offers some unusual sounds at unpredictable moments. The singers change the shape of their mouths to crossfade vowel sounds into each other. Sometimes these tones are morphed beyond the domain of spoken languages and they start to resemble the calling of mythical sirens, or throat-singing monks, or flutes. Whistling takes over the function of singing every now and then. Some voices change their textures rhythmically, almost as if they stutter. This is further exaggerated in parts where the singers move a hand in front of their mouths rhythmically. I couldn't catch Capella Amsterdam making any mistakes, really; every (odd) sound came out clear and focused. I found the piece sonically enlightening, as sounds that I had never experienced before touched my soul. (It's available for listening on Spotify.)

Of Philip Glass' Three songs for chorus (1986), the most memorable was the first song, 'There are some men'. Capella Amsterdam brought the lyrics, written by Leonard Cohen, to life on typical Glass harmonies. Contemplative and powerful moments alternated with each other. Glass takes distance from his minimal tendencies and varies note lengths and volumes. The composition contains some repetitively alternating notes, but no wild arpeggios. It gives room for melodies to serve as ornaments on the harmonies.

Arvo Pärt's ...which was the son of... (2000) is based on a very simple Biblical text that runs through Jesus' forefathers, from Joseph all the way to God. Within the linearity of the text Pärt sets out a variety of harmonies, tempos, note lengths and choir divisions, like a procession through a landscape of fields, hills, towns and cities. Capella Amsterdam travelled through these progressions with natural ease. My brain thought it recognized similarities to old Medieval polyphony as well as new American gospel. But it feels as if Pärt simply glued his influences together, instead of fusing them into something new. The piece failed to surprise or really captivate me, especially in the light of other magnificent choir works of Pärt that I know.