Creating sound has been achieved by every (successful) musical instrument ever made - but usually, aside from the musician using some form of articulation to modify that sound, there's a fixed range of timbres an instrument can make. A guitarist can make a mellower sound by using their fingertips rather than a guitar pick; a violinist can play pizzicato or vibrato; all these techniques take skill and all are relevant, but none offer complete control over the sound, or create a brand new sound.
A synthesizer lets you do just that. There are many types, based on a range of different audio principles but fundamentally, they give you the ability to modify in detail the characteristic of a sound to create new sounds - and in many cases, let you recreate sounds from acoustic instruments or music you've heard. From Pink Floyd, to Michael Jackson, to Mark Ronson and Calvin Harris - synthesizers are essential to modern mainstream music producers - and there's a whole underground of artists creating purely synthesizer-based music.
If you're new to synthesis, we recommend our reface CS Synthesizer. Don't be put off by its diminutive size - it's built like a small tank and the keys are very playable - but crucially, our renowned 'AN' virtual analogue synthesis engine lies inside. This offers enormous breadth of tone and gives you easy-to-understand hands-on control over the sound; very quickly, you'll learn not only what each control does, but how to build a specific type of sound using all the controls together.