Dub Sirens are monophonic synths that can produce sound at different levels, pitch and frequencies. They gain the popularity in the Raggae and Dub music genre, their sound became present in almost 50% of the songs, most of the time used along with a delay and reverb effects processors.
The sirens are analog, that means they will all sound slightly different one from another, in an unique way, depending on the parameters of electronic components and their tolerance (0.1-5%), the only integrated circuit is a LM7809 used to stabilize the voltage from power supply so the sound produced will have a minimum amount of noise.

Projected in Eagle from an open source diagram and transposed in Sprint Layout, at the very beginning I was creating the PCB’s manually with cooper board, printed the circuit on photo papers, transfer the tonner to the cooper layer(tutorial), then let them sink in ferric chloride(FeCl3). Now I found company’s in China that will make this job at a higher professional level, for only 2$ per PCB, including drilling holes, silkscreen, solder mask, even the color. JLCPCB.com