Carbon microphone
The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone (then called transmitter). This was independently developed around 1878 by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention.
Magnetophon
Magnetophon was the brand or model name of the pioneering reel-to-reel tape recorder developed by engineers of the German electronics company AEG in the 1930s, based on the magnetic tape invention by Fritz Pfleumer. AEG created the world's first practical tape recorder, the K1, first demonstrated in Germany in 1935 at the Berlin Radio Show.
Later models introduced the concept of AC tape bias, which improved the sound quality by largely eliminating background hiss. The resulting reproduction was so great an advance on any existing recording method that even those well acquainted with the industry could not tell the recordings from live play. Adolf Hitler used these machines to perform what appeared to be live broadcasts from one city while he was in another. A cache of 350 of these tapes was released years later when they were found in Koblenz.