Audiotent Tip 385. Riser and Fall FX Sound Design.
Creating synth effects can be a great way to build tension or anticipation in your tracks.
Make sure to utilise the modulation parameters of your synth to get more complex sounding patches.
For riser and fall FX, assign long envelopes to the main pitch.
Finally, adding a touch of delay or reverb will help to create a sense of space and position them smoother in a mix.