Intrigued by the title, I discovered that aq'ab'al refers to a Mayan calendar symbol for dawn and dusk, or for polar opposites generally. I'm not sure how opposite they are, but Costa Monteiro and Garcia are two of the most uncompromising spirits on the current improvising scene and any collaboration between them was going to be worth hearing (there's another recent recording, 'Ate Gena' on the Geräuschmanufaktur label that I've not heard).

It's pretty ferocious. From the first second, the pair (each simply credited with "electronics") launch into extreme slabs of thick, viscous noise, layer upon layer, screaming, metallic shards melting over subsonic bass bellows and much between. It's almost as if they recorded some immense grinding mechanism, feeding into it jagged remnants of metal, letting the stretching and crushing resonate through the body of the device and recorded that too, feedbacking it into its maw, over and over, building the noise. There's something vaguely cyclic about parts of the four pieces, a pulse or rhythm that emerges briefly, disappears, is replaced by another, something that hints at a machine nature although, given the provenance of the title, I sometimes think of those massive, carved-stone Mayan calendar wheels, grinding inexorably. It's difficult to describe this maelstrom otherwise. There have been thousands of noise records over the years, many of equal volume and ferocity, but few that I've heard with the pure, unrelenting tensile strength and density of this one. It's molten, blessedly unforgiving.