Airbow, you'll hear the violin playing of Sven Ahlbäck, who complements the sparse wintry sound on that album perfectly.
What Kalaniemi and Hayes have in common is beautiful phrasing. You'll find quietness and fire in their work - maybe not enough fire for some ears, but it works just perfectly for me. If neither instrument is something you associate with grace or beauty, dig in. They make such excellent music - Hayes and Cahill with The Lonesome Touch and Live in Seattle, and Kalaniemi on the album mentioned above (which you can find to sample as a download if you dig through these archives) and on Bellow Poetry. And these albums are just a beginning. I've not heard anything by either of them that is not stellar.