Slap the bayan with the flat of the left hand — fingers and palm landing together and staying on the skin, so the sound is a dry, damped consonant. It is the bass side's closed counterpart to Ge's open ring.
Ka carries the khali logic on the left hand and supplies the "k" syllables inside composite words — Tirekite's Ki, Taka, and Kat all draw on the same family of flat-hand closures, differing mainly in weight and how much of the hand lands. A clean Ka is felt as much as heard: crisp contact, zero after-ring.