A synthesizer can imitate any sound, so it is read as invention, change and the freedom to reshape yourself. Dream books also link it to modern life and to the line between the real and the made.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.