You've probably heard that 'yoy' sound a million before times in Dubstep tracks. Here's how to make it in everyone's favourite freeware softsynth.
If you're still unsure of what I'm referring to, here's a quick example.
Open Synth1 and try to get it somewhere near an initialized patch, i.e., a blank slate to start from. Try turning the mix knob all the way to left to use just the first oscillator and set the oscillator's shape to sawtooth. Turn the filter envelope amount knob to the 12 o'clock position and turn off the delay and chorus effects. Finally, turn the amplifier envelope's attack and release completely down and the sustain all the way up.
It should sound quite boring, like this:
Now, to make it wobbly, make sure the first LFO is turned on and set it to affect the filter. Tweak the amount and speed knobs around and have a little fun, but we'll be coming back to them later.
Here it is, wobbly, but still boring.
In the effect section of Synth1, in the top right, click the 'On' button to enable the effect. Choose the weird digital lo-fi effect by clicking the enigmatic letters next to the button and selecting 'deci' from the list that pops up.
Staying in the effect section, turn the 'ctrl 2' knob all the way down. This is the bitcrusher, which we don't really need right now. Turn the other knob to around 30° or the 10 o'clock position. This is the freaky sample rate reducing artifacts effect, which is what makes the formant-like vowel sound.
Here it is, almost complete.
Now all you need to do is adjust the filter until you can hear the 'yoy', probably by turning the cutoff frequency down and the resonance up, mess around with the LFO settings and you're done!
Here's the final product: