Tha is the title of the second track on Selected Ambient Works 85-92, Aphex Twin's first ambient album, some of which was written when he was only 14. The album itself is a milestone in the emergence of ambient music as a distinct genre with its own inner logic, and Tha is the album's most ambient track. Over nine minutes long, it consists of a subtle, driving beat over which a deep, spare melody drifts. In the background you can hear indistinct voices that sound like they were recorded within a train station.
What made me fall in love with this album was the realization that, beneath the music, even beneath the audible voices, if you turn the volume way up and have a good set of speakers, you can hear something else, a kind of babbling noise following the beat, like many voices shouting together, or like the indescribable sound accompanying a feverish hallucination. This gave me a very eerie feeling, as if I'd discovered ghostly voices on a blank tape
At the very end, this strange noise disappears, usually without the listener even realizing it was there, and the resulting silence is incredibly deep. In fact, the whole track is like a postponement of silence, a kind of musical lesson about what silence is and how everything eventually comes to rest. One of my favourite memories is of listening to it while travelling on a train into the countryside, looking at distant figures walking along a long Dublin beach under a deep blue dusk.