 
 <prompt> Wetin be di first machine wey dem mention? Based on di last question, write one context wey get di answer. E fit be 1 - 20 sentences. Context: <response>: Eventually, when e dey common for electric recordings to dey play back electrically for di 1930s and 1940s, di overall tone bin dey like as you dey listen to radio for dat time. Magnetic pickups dey more common and dem dey better designed as time dey go on, wey make am possible to improve di damping of spurious resonances. Crystal pickups sef dey introduced as lower cost alternatives. Di dynamic or moving coil microphone enter market around 1930 and di velocity or ribbon microphone for 1932. Both of these high quality microphones dey popular for motion picture, radio, recording, and public address applications. 