Using “reverse LA synthesis” to make paraphonic mode more polyphonic

[BrettM]

The resonant filter sweep of a saw or square wave chord is a classic sound of a polyphonic synth, and is especially useful for creating pads.

 

The usual starting point for creating this sound on an XW synth would be “paraphonic mode”, as described in AlenK's XW Companion Rev 4, Section 6.6.3.1. Paraphonic mode refers to a Performance configuration in which PCM tones in Zones 2-4 are routed through the solo synth in Zone 1, thus allowing chords to be played through the solo synth's resonant filter and effects section. What makes this mode paraphonic instead of polyphonic, even though a chord can be heard, is the presence of the single filter. True polyphonic synths have a separate filter for each note, whereas the XWs have only one resonant filter for all notes. If you want a chord that shuts off as soon as you release the keys, paraphonic mode is fine; but problems arise when trying to play chords with a long, lingering release because the single filter will reopen as soon as you play the next chord, spoiling the filtered release portion of the previous chord.

 

A possible solution to this problem is to extend the basic paraphonic mode set-up, but cross-fade the tone into a heavily filtered version of itself with a much longer release in the next Zone. This filtered version does not pass through the solo synth, it has its internal PCM cutoff set permanently low so its release is not spoilt by the reopening of the solo synth filter when the next chord is played.

 

For example, say you wanted a to create a classic resonant filter swept sawtooth chord. Start by saving two copies of one of the PCM sawtooth tones. Fully open the PCM cutoff of the first copy, so the resonant filter has plenty of harmonics to work on, and set its release a little above zero so it fades quickly, but not too abruptly, on key release. Save the second copy with a fully closed PCM cutoff and set its release to be as long as desired. This muffled second copy will produce the lingering, polyphonic release of the overall sound. Now create a Performance with the solo synth in Zone 1, the first copy of the sawtooth in Zone 2 and the second copy of the sawtooth in Zone 3. Enable the DSP line for Zone 2 but not for Zone 3. This causes Zone 2 to pass through the solo synth and the resonant filter while leaving Zone 3 to simply play the muffled second copy of the sawtooth independent of the solo synth. Finally, set up a nice filter sweep in the solo synth. A bit of tweaking of the release of the Zone 2 tone may be necessary to get the fading between Zones 2 and 3 just right and you may also want to slow the attack of the Zone 3 tone.

 

It's now possible to play resonant filtered chords with long filtered releases, just like on a real polyphonic synth, perfect for pads.

 

This technique might be called “reverse LA synthesis” because it focuses on the release stage of the sound rather than the attack, see AlenK's XW Companion Rev 4 Section 6.7.1.1 for a description of LA synthesis.

[AlenK]

Very nice. I'll have to give it a try. Any chance you could upload a zip with all the required components, such as I have done a couple of times (and will do again, when I have more examples to share)?

 

[BrettM]

I've uploaded a demonstration here: http://www.casiomusicforums.com/index.php?/topic/14264-making-paraphonic-mode-more-polyphonic/&tab=comments#comment-42837