The Casio VL-1 synthesizer
When I was a child, I inherited a Casio VL-1, which I always considered a "toy piano." What I didn't realize was that I had in my hands the first commercially available digital synthesizer in history.
The VL-1 was a combination of a piano, sequencer, and calculator. It featured six sound presets: piano, fantasy, violin, flute, guitar, and ADSR. I never quite understood what ADSR meant, as it came into my possession without a manual.
Although it was a monophonic piano (capable of playing only one tone at a time), it allowed for background tracks, tempo adjustment, and even tuning by adjusting a dial with a screwdriver.
I was always amazed at how such a seemingly simple piano had so many features. Perhaps that's why I occasionally recognized its distinct sound in certain songs, like "Da Da Da."
Since all the notes corresponded to some number or symbol on the calculator, which was labeled on the piano, I transcribed many melodies into a notebook using that notation.
In addition, I discovered that storing a number in the calculator changed the ADSR instrument's sound. I spent many afternoons experimenting with random codes and noting down my findings in the same notebook.
Theremin 3 9 9 9 9 9 5 4
Oboe 6 1 0 7 9 1 3 0
Human voice 0 0 1 2 3 1 2 3
Banjo 2 0 3 4 2 0 0 0
When I finally got internet access at home, I managed to download the manual, and I finally understood the logic behind these codes. It was a digital synthesizer that allowed taking a base instrument and modifying its parameters, something that had never been done commercially before.
The way to combine so many functionalities into something so simple and crude in appearance has turned this Casio instrument into a cult object, similar to their classic wristwatch F-91W.
Today, it's possible to find countless guides to modify the synthesizer, emulators for musical software or covers of songs. This seemingly modest piano has had a significant influence on modern synthesizers.