Bay seniors balking at the price of hearing aids ($4,000 and up, up, up) will be relieved to hear that audio researchers are busy creating devices that will make it possible for us to join in conversations at even the most raucous restaurants. Directional microphone apps for your iPhone that filter out excess noise are only $30 on Amazon. You just lay it on the table and point it at whoever’s talking. SoundAMP R uses earphones to amplify music on your iPod or iPhone for $5.99. Maybe the most exciting developments are audio induction loops, coils that sharpen and amplify sound on tv and cds and are starting to be installed commercially in theaters. The Geezer would like to hear from anyone who’s had success with these or similar gizmos.