As Spunjer and Nacho said (who are both from Iloilo, Panay), it's a
binangon ... pronounced bee-NUH-ngon, the last syllable pronounced a la Kli
ngon in Star Trek
Unfortunately the art of working with carabao horn has been largely lost, as Nacho said. Am planning though to visit one off-the-beaten-path island in the Philippines where the tradition is supposed to be still alive ... not sure if the report is true, but we'll see later.