This technique can be used on almost any synthesizer and involves manipulating a low-pass filter to reveal the synth’s tone.
Slowly Emerging Sound
Below is an example of the sound using the MiniFreak synth, but this can be done with any synth that has a built-in low-pass filter section where the cutoff can be tied to the envelope. Watch the filter section and note how the filter moves as this is what makes that slowly revealing sound.
To get a slowly emerging sound when playing a key, use a low-pass filter to gradually open and reveal it.
Basic Moving Low-Pass Filter via Envelope
Set up the filter to move based on an envelope.
In the basic case, a low-pass filter (LP) in the FILTER section has the envelope amount (Env Amt) turned down slightly, making the cutoff jump low (CCW) and gradually increase, making the filter move left and cut out sound when a key is pressed, then gradually allow it in. You can leave it at this and get something really quite nice-sounding that you can use a variation of on almost every patch to some extent.
Advanced Movements of the Low-Pass Filter
For even more adjustment and nuance, more controls can be added and linked.
In the example at the top of this post, the cutoff is linked to the Cycle Envelope (CycEnv) in the MATRIX section, so it initially moves upward and then slowly moves downward when a key is pressed. Now this is working counter to the envelope amount adjustment we previously made. However, it introduces variation because the envelope amount control prior follows the envelope, and this adjustment follows the cycle envelope, which is a completely different envelope.
And the same thing is done with the Env Amt of the filter in the MATRIX, where it is tied to the Envelope and decreased, so it initially pulls it downward, then allows it to return upward again, following the envelope.
Even more change can be felt by the user if the velocity of the keypress changes the filter, which it does in this example, because the cutoff of the filter is linked to the velocity of the note played, and you can see this in the MATRIX.
There’s one other control in the matrix section for this example: the pitch is ever so slightly controlled by LFO 1 to give the synth a slight warbling effect, and it’s not related to the filter at all.
Applicability and Variation
You can apply this type of filter manipulation to most patches, and variations include changing the direction of the envelope amount to initially open the filter, then pull it back, or even switching to a different filter while employing the same scheme.