Police Siren - Runaway Baby / Bruno Mars

bardberntsen · Post by **bardberntsen** » Fri Aug 27, 2021 5:52 am

Anyone have a patch for this police siren sound for the Kronos? Or simple programming tips?

CharlesFerraro · Post by **CharlesFerraro** » Fri Aug 27, 2021 8:50 pm

Couple months ago I made a police siren in that style. It was part of an environmental sound. You can listen to it here: https://soundcloud.app.goo.gl/uiYKahEDUBuvG5zt8
Here are the notes for the client concerning the siren itself.
“It's a sine going through diode type asymmetrical distortion. The gain into the distortion is being modulated very slightly by the pitch EG for the sine (+2dB). That pitch EG has a modulation depth of 17 semitones from C#4 to F#5. The attack has a small convex curve and lasts 1.776 seconds. The decay lasts 3.808 seconds and is linear. No sustain of course. The envelope is retriggered every four bars at a tempo of 174.61bpm.”
You should be able to find EG times here on KorgForums. Just do a search, I posted them somewhere. Use MOD-7 to create the patch. Then put it through reverb to sound like the Runaway Baby intro.

average_male · Post by **average_male** » Fri Aug 27, 2021 10:45 pm

Really? You can make that siren sound from scratch on a Kronos? What you described sounded pretty complicated, and chance you could put together a video on this?

KingKronos · Post by **KingKronos** » Tue Aug 31, 2021 4:05 pm

Nice one, Charles.
MOD7 is my favorite engine.

@average_male
There are 2 parts to making the siren.
One is to get the pitch changing like a siren.
Charles' second tip about distortion just adds grit.

Here's a super quick guide to doing it yourself.
(From memory, not at Kronos atm):

1) From an INIT EXi, choose MOD7 as the engine.
- Common / Basic, engine type at top of page

2) Select the Osc1 tab.
- notice waveform is sine by default
- change this to Sine + waveshaper
- below this, in middle, touch the detune
- now notice in upper right you have Pitch mod options
- choose Pitch EG, amount to +17 (per Charles' tips)

3) go to Pitch EG tab
- follow Charles' settings
- tweak by ear

4) For the bit of distortion:
- go back to Osc1 page
- on bottom left is the Waveshaper section
- change the WS to Diode 1
- touch the Drive box
- notice upper right window now shows Drive mod options
- choose Pitch EG, amount +2dB (per Charles)

Good luck!

KingKronos · Post by **KingKronos** » Tue Aug 31, 2021 4:09 pm

For some extra credit points:

Check out the Doppler FX.
This simulates rising and falling pitches of moving objects.
Like from ambulances, trains, jets taking off, etc.