Making a siren sound on your keyboard or guitar can create an intense and dramatic effect in your music. The beginning to "Blockbuster" by the glam band Sweet has a droning air-raid siren sound at the beginning, for example. There are multiple siren sounds, and each adds its own effect. For example, a police siren sound adds an element of danger to your music. Sirens are typically comprised of one or two pitches in a high key. You can emulate a siren sound using a standard electric keyboard or electric guitar.
Turn the guitar up to full volume and add distortion and reverb. This gives the sound more resonance. Pick any note above middle C. Play the note and let it ring for one beat.
Bend the string upward to increase the pitch by two steps. For example, from G to A, or D flat to E flat. Let it ring.
Release the string without picking it and let it gradually return its original pitch. Repeat the string bend.
Select a resonant, monophonic sound from your tone bank, such as "Lead Synthesizer." Play any note above middle C and let it ring for one beat.
Move the pitch-bend joystick forward so that the note increase in pitch by two steps.
Release the pitch-bend joystick slowly so that the note returns to its original key. The bend and release should last for one beat. The air-raid siren sound has a smooth pitch transition. This technique is called portamento. Increase the length of the original note, the bend and release for a more-distant siren sound.
Play any note above middle C for one beat. Keep the same sound that you used for the air-raid siren, but turn off your reverb effect.
Play the note that is a perfect fourth interval below the original note. For example, if starting on C, drop to G. If starting on D, drop to A. This note is almost always on the string above the one you are playing, on the same fret. Unless your start note is on the B string in which case it is one string above and one fret below. Play the low note for one beat.
Repeat the pattern at a steady rate. The police-siren sound has two distinct notes that step up and down in pitch.
Select a monophonic, resonant sound. The same sound that you used for the air-raid siren is fine.
Play any note above middle C. Hold for one beat.
Play the note a perfect fourth below. This is the note five keys, including black keys, to the left of the original. Hold for one beat before returning to the original note.
If your keyboard doesn't have a pitch-bend control, use the portamento setting and play the note two steps above.