"The gap of dreams is never shut," a line from a poem by Francis Collins, provides the title for Altan's latest album. It does the same for the opening number, composed by band founder, fiddler and vocalist Mairead Ni Mhaonaigh. Collins evokes the link between Irish music and the Otherworld of fairies and ghosts, not just just legend or metaphor to those who believe they have been swept up in it personally (the subject of a fascinating book, with accompanying CDs, The Otherworld: Music & Song from Irish Tradition, published by the Folklore of Ireland Council in 2012; I reviewed it here on 18 May 2013; see also, more recently, Simon Young and Ceri Houlbrook, eds., Magical Folk: British & Irish Fairies 500 AD to the Present, a scholarly survey of centuries of extraordinary experiential claims published in 2018).

The Gap of Dreams contains no songs or tunes -- yes, such exist -- said to have been learned from fairyfolk or the dead (the two categories sometimes overlap in supernatural lore), but it is imbued with the dark, not quite earthly sensation one may experience listening to native Irish music at its most intense, when one's sense of the quotidian realm fades into an aural landscape whose features are at once familiar and strange. Altan has been at it for three decades now, and on its new release the music sounds better than ever which, given the testimony of its recordings (of which this is the 13th, not counting live releases and collections), is something of an extraordinary claim in itself.

Though my collection houses more than half of Altan's output, I managed to miss its previous release, The Widening Gyre (2015), which incorporated non-Irish elements into the band's sound -- in the fashion, I infer, of the Chieftains -- perhaps explaining a remark I read in a British magazine at the time. Ni Mhaonaigh said she no longer wanted Altan to be known as a traditional Irish band, just a "music" band. My heart sank. After all, there are plenty of "music" bands around and all too few for-the-ages Irish folk bands.

Perhaps that explains a slightly defensive observation Altan's longtime guitarist Daithi Sproule offered as Gap was being recorded in a studio in rural Donegal. This is "a back to the roots effort," he said, adding hastily, "Not that we ever left our roots." The new release is a dive into the deepest and richest soil of tradition: dance tunes in all their variety, airs, Gaelic laments, English-language ballads, new pieces with debts to the old. The late master Bill Monroe was inclined to say that at its most grounded and soulful bluegrass calls up the "ancient tones." Gap does the same for what is in some ways bluegrass's Irish counterpart.

I have never heard Paddy Tunney's version (Altan's source) of "The Month of January," among the loveliest and most harrowing seduced-and-abandoned songs in any tradition, but I have long known Sarah Makem's, which has stopped time on any occasion it's been within my hearing. There isn't, nor should there be, any competition in these matters, but let it be said that Ni Mhaonaigh's makes for 5:48 of memorably broken, frozen heart and piercingly chilling sentiment. Another unrequited-love lament, "Dark Inishowen" (Inishowen is a town in County Donegal), boasts an affectingly poetic adjective in its title, to which full honor is paid in the vocal and instrumental arrangement.

Beyond its Irish allegiance Altan sometimes feels like a country of its own.