Downward spiral 1 & 2 — two versions of a rising/falling pitch reverb

The Meris Mercury7 strikes again as a source of inspiration (not NIN, although I really should listen to that record again with an ear to ZOIAing… lot of good sounds in there, too). In particular, the pitch regeneration modes that allow for ascending and descending pitches across the reverb decay. Something about that sound makes me want to… figure out if I’m a Replicant? It’s a very atmospheric, sci-fi sound, almost more of a “sound effect,” than an effect. It transports me.

Pitch regeneration on ZOIA is tricky. The pitch shifter seems easily overwhelmed, and the reverb modules tend to shut down at the slightest hint of a feedback path. So, the pitch regeneration is separate from the reverb; it uses a delay line to control its rate, with a diffuser also placed in the feedback path to try to smooth out the repeats some and make them a little less “delay-y.”

Which is why there are two versions of this patch. I kept going back and forth between two signal paths, and ultimately, I just couldn’t decide which sounded better to me. So, I included both, and to let you choose or use both.

Downward spiral 1 — the signal path here is reverb, which is then split into two paths. One goes to the output mix, the other goes through pitch regeneration. To my ears, the advantages here are the longer reverb times allow for more sustained pitch curves. The disadvantages are that, especially as the ‘rate’ (i.e. delay time) of the pitch regeneration is increased, the effect can sound more ‘separated’ from the reverb itself.

Downward spiral 2 — the signal path here is pitch regeneration, which is then fed into the reverb. The advantages/disadvantages tend to break down inversely: the pitch regeneration is less sustained, but it feels more fully integrated into the reverb.

If I had to pick, I would probably choose 2. But I didn’t want to, so both are here, with their subtle differences intact.

At a lot of settings, it’s really hard to tell the two apart, though.

Both versions are stereo throughout.

A special thanks to my patrons on Patreon for their support: Rob Flax, Stepan Grammatik, brockstar, Mats Unnerholm, D Sing, Will Scott, drew batchelor, Miguel, Steve Bragg, Joab Eastley, Tomi Kokki, Mitch Lantz, Ben Norland, and Daniel Morris!

If you would like to support my work on ZOIA, please visit patreon.com/chmjacques

Controls:

Stompswitches:

Left, latching — toggles pitch regeneration on and off; when pitch regeneration is off, the patch functions a lot like a shimmer (or any other pitch-shifting) reverb

Middle, latching — reduces the reverb mix to 0% (a bypass hack; the reverb is still processing input, but none of its output is heard); when reduced to 0%, the patch can produce some, ahem, Rainbow-ish sounds

Front page:

There are three white controls, which relate to the pitch regeneration aspect of the patch:

Pitch rate — sets the time of the delay line in the regeneration circuit; as there is no interpolation (to save CPU) so as you adjust this, you may hear some clicking. In Downward spiral 2, this control also acts as something of a ‘pre-delay’ for the reverb. The regeneration rate ranges from ~35 msecs to 1 sec

Pitch feedback — sets the amount of pitch regeneration that occurs; at high amounts it can reach near self-oscillation

A white light beneath this control will also go bright when pitch feedback has been disabled using the left stompswitch.

Tone — there is a low-pass filter at the end of the regeneration section, which is very useful for taming some of the ascending pitch sounds

There are also two aqua pitch shifter modules, labeled ‘left PS’ and ‘right PS’ — you can set the pitch-shift different amounts on either channel; with widely divergent shifts (e.g. -1 and +1 octave) this… sounds odd. But especially with changes in the range of cents (e.g. +/- 20 cents) or complementary intervals (+7 semitones and +1 octave), the differences can be more musical.

There are also two magenta controls for the reverb module:

Reverb decay — familiar; at 1.000 the reverb will be frozen

Reverb mix — controls the mix of the reverb; when the mix is reduced to 0%, a magenta light beneath this control will go dim

Finally, there is a blue control for the wet/dry mix of the patch.

Revision note 1.1:

Brock Davisson alerted me to the fact that these patches were prone to gain. I have addressed the matter to a degree by adjusting some levels within the patch. Unfortunately, eliminating the possibility of clipping is almost impossible: one of the reasons creating feedback loops with pitch shifters is difficult is because they produce a fair amount of gain. If I eliminate the possibility of clipping ever occurring, it also means reducing the levels of the pitch shifters to the point where the effect becomes almost undetectable. In making these adjustments, I tried to walk a fine line between reducing the likelihood of clipping while keeping the pitch effect as present as possible; there is no ideal middle ground there, only compromise.

Which is to say, you may still experience clipping using these patches (although it is less likely than before). You may try reducing the feedback level, or, alternately, turning down the input signal and increasing the patch’s output (the gain control for the patch is starred and the output is located on the second page).

Sound clip:

For the sound clips, I tried to set Downward spiral 1 & 2 to similar settings and play them back to back.

For all clips, the reverb is unchanged: decay at ~.68, mix at 1.00. Pitch regeneration is always engaged and the feedback is left at 1.000, as is the reverb mix. Wet/dry mix is set to 50%.

First clip:

PS left — slight pitch down (-20 cents), PS right — slight pitch up (+20 cents), rate ~.500, tone ~.75.

Second clip:

PS left — +1 octave, PS right +7 semitones, rate increased to ~.750, tone cut to ~.60.

Third clip:

PS left — -1 semitone, PS right — +1 semitone, rate increased to ~.900, tone set to ~.66.

Fourth clip:

Switch to synthesizer.

PS left & right — -20 cents, rate ~.85, tone ~.60.

Fifth clip:

Different synth patch.

PS left & right — +1 octave, rate ~.85, tone ~.60.

It was at this point I realized… hey, since Downward spiral 2 is always louder at the same mix, maybe there’s something that could be done about that. So, the levels of Downward spiral 2 were adjusted while recording this clip, so that the two align more in output (and are more even with the dry signal).

2 comments on “Downward spiral 1 & 2 — two versions of a rising/falling pitch reverb
  • tomikoo on said:

    Holy sh…. this sounds incredible! This is also a keeper!

    PS. I seriously think Empress needs to make it possible to save more than 64 patches! My ZOIA starts to be a full of CHMJ patches with this rate. :D

  • dantahoua on said:

    Hey I love this patch. But is there a way to have the downward effect more present? You know like on the Mercury 7, the down pitch or the anti-shimmer on the Specular Tempus… This kind of infinite Shepard Tone, creepy, always going down tone. I would like to have it stronger without having the reverb overwhelming the direct sound (this part I can manage, just a question of mix. :) ).

  • Leave a Reply

    Download
    Chat