Instantenous aluminum disc
Instantenous discs were used in the 1920's - 30's mainly in broadcasting houses. Those discs usually had an aluminum base with a laquer coating on both sides. The recording was carved to the laquer surface.
There were also plain aluminum discs in which the audio groove was carved into the aluminum itself. There were different sizes of aluminum discs, but these are five inches in diameter. These discs were one type of audio letters.
These Voice Records were manufactured by Amusement Equipment Co. in Wembley, Middlesex. There were small recording shops or booths, where people could drop in and make recordings of their own. One side of the disc was intended for the message that was spoken or sung into a microphone. The disc was carved in real time and the customer got the recording with him or her right away and could send it in a letter for example to a friend or relatives.
On the other side of the disc is a sound advertisement by Amusement Equipment. (Use Back-button to return here after listening.)
The maximum duration of the recording was about one minute and fifteen seconds. The disc was intended to be played by the gramophones of the time at 78 RPM speed. However, as steel needles could have damaged the softer aluminum disc material, wooden needles were recommended. Sometimes a tiny paper envelope of bamboo gramophone needles was sent with the disc.
If you happen to find this kind of a disc, do not try to play it with a microgroove stylus, or actually, any stylus. A playback attempt with a wrong size stylus and too much weight may cause damage to the groove and remove some audio modulation in such a way that it cannot be recovered. Remember, these discs are original recordings and no copies exist.