The past weeks I have been listening to the Clarinet Quintet, op 146, a lot. It's Reger's last completed work, before he died at age 43.
I seem to have three recordings, Karl Leister and the Vogler Quartet; Sabine Meyer and members of the Vienna Sextet and Sharon Kam with Isabele van Keulen, Ulrike Anima Mathé, Volker Jacobsen and Gustav Rivinus. All are very good performances (although I have long ceased to be a fan of Leister), but at the moment I prefer the Kam recording, if only because they avoid at all times a cloying sound in the strings, which the Vogler Quartet don't always do. I should get the new CPO recording with the Diogenes Quartet soon.
The work is extraordinary. I rate it higher than the Brahms quintet, which I find playing into the soaring clarinet thing too much. Reger often lets the clarinet merge, if not submerge, in the strings. There is a lot of pp writing for the wind instrument. It goes both ways; in the Scherzo's Trio the upper strings play shimmery figures that make them sound like wind instruments.
It's also a work of radical (faux) simplicity for Reger. The Largo in E major has a lot of chromaticism after the opening bars in simple E major, however the lines never get clogged. It's intriguing to find that in the entire work motives reappear, particularly a three-note chromatic motiv that keeps driving all four movements. The simplicity climaxes, as it were, in the last variation in the finale, when the strings are reduced to rhythmic accompaniment for a dozen bars, just to give the clarinet one last song.
In spite of the apparent serenity there is a kind of impatience to op. 146. There are no exposition repeats, and in the variation finale there are no repeats either. Everything is over when it's over, and it's off to the next thing, which is quite devastating if one thinks it's Reger's valedictory work which he himself never got to hear. Another intriguing structural thing is the final variation movement is constructed on a vaguely incomplete sounding theme, seventeen bars long, instead of the eighteen bars you'd expect.