> Can someone explain what a synthesizer is to a non musician?
Keyboard = input device, usually generates MIDI. Synthesizer = creates sounds from scratch, usually generates audio from MIDI.
Some keyboards are not synthesizers (sometimes called a "master keyboard") and you have to plug them into something in order to get sound. Some synthesizers are not keyboards, and you have to plug something into them to control them. For example, the DX7 is both a synthesizer and a keyboard. The TX-802 is a synthesizer but not a keyboard... it is kind of like two DX7s in a 2U rack-mount unit without a keyboard. The Akai MPK249 is a keyboard but not a synthesizer. You can buy a TX-802 and an Akai MPK249 and plug them into each other, and it's kind of like having a DX7.
> Also, in today’s world, do these need to exist in the same form? That is, can’t all these sounds simply be digitally produced rather than relying on circuitry?
Circuit emulation has varying degrees of accuracy. I like to think of digital synthesizers as computers that don't ever need software updates, and are therefore more reliable than software running on a computer. They also often have purpose-built UIs (knobs, buttons, sliders) which are critical to some people using them.
If you are going to make a custom input device, why not just make the custom input device and the synthesizer one single package? This is called a "sound module" -- something that makes sounds but does not have a keyboard attached. They come in both rack-mount and desktop versions.
Keyboard = input device, usually generates MIDI. Synthesizer = creates sounds from scratch, usually generates audio from MIDI.
Some keyboards are not synthesizers (sometimes called a "master keyboard") and you have to plug them into something in order to get sound. Some synthesizers are not keyboards, and you have to plug something into them to control them. For example, the DX7 is both a synthesizer and a keyboard. The TX-802 is a synthesizer but not a keyboard... it is kind of like two DX7s in a 2U rack-mount unit without a keyboard. The Akai MPK249 is a keyboard but not a synthesizer. You can buy a TX-802 and an Akai MPK249 and plug them into each other, and it's kind of like having a DX7.
> Also, in today’s world, do these need to exist in the same form? That is, can’t all these sounds simply be digitally produced rather than relying on circuitry?
Circuit emulation has varying degrees of accuracy. I like to think of digital synthesizers as computers that don't ever need software updates, and are therefore more reliable than software running on a computer. They also often have purpose-built UIs (knobs, buttons, sliders) which are critical to some people using them.
If you are going to make a custom input device, why not just make the custom input device and the synthesizer one single package? This is called a "sound module" -- something that makes sounds but does not have a keyboard attached. They come in both rack-mount and desktop versions.