H9 Shimmer – Pitch decay etc

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    • #113168

      hi, trying to understand the diferent functions of penultimate knob which changes it’s name and doen’t quite line up with the guidance docs or the inbuilt info. I’m using it with the control app on a PC.

      For most it’s travel is “Pitch Decay” – what is that?

      At 100% it becomes “Freeze” is that indefinate sustain of whatver goes in or only freezing in the moment it hits “Freeze”? Then it becomes Pitch+Verb and goes to “FRZ” ?



    • #142181

      No takers yet?  It’s a very complex algorithm structure.  I don’t have any insider information, but I can tell you how I approach Shimmer myself; right or wrong.  The exposed parameters are interconnected and interactive.  So it’s difficult to discuss one control in isolation, without first explaining some of the other controls that affect it.

      Reverb is first in line, and always present.  DECAY and SIZE at 0 set the minimum amount of influence (and also determine the ‘shape’ and diffusion of the reverb).  It branches off to a DELAY line, that’s always at least 50 mS (for processing); up to 1000 mS.  Think of the LOW-DECAY, HIGH-DECAY, and MID-DECAY as a multiband mixer to the inputs of the A-PITCH and B-PITCH shifters.  One or more of these frequency bands needs to be above 0 to send some amount of signal to the pitch shifts.

      PITCH-DECAY is the ‘master’ control after the pitch shifters & the blend of frequencies sent into them.  It’s also the feedback level for the path starting with DELAY, through ‘frequency mixer’, & into the pitch shifters.  Then all that is fed back into the reverb up front, within a range from 0-100.  So it’s the PITCH-***** level, plus the *****-DECAY level for the whole feedback loop.

      I don’t think the PITCH: FREEZE / PITCH+VERB: FRZ variations here have a counterpart in any of the other algorithms.  Shimmer’s FREEZE is somewhat like ‘INF’ values in the other algos, but not quite.  It won’t hold infinitely; the frozen sound degrades and disintegrates fairly quickly.  I suspect because it’s fed back into the reverb, and ‘blurred’, or carved up by running through the frequency bands repeatedly.  In addition, input signal still runs through the active reverb.

      And PITCH: FREEZE disconnects from the pitch shifters.  Any DELAY time fed back around is at the original input pitch.  In other words, it can be used as a ‘conventional’ delay line that follows an omnipresent reverb, with regeneration and filters.  There’s just no pitch shifting at this particular value.

      PITCH+VERB is closer to the ‘FREEZE’ setting found in other algorithms.  Input signal comes through ‘dry’, and whatever reverb / pitch / frequency spectrum that’s captured is held indefinitely, recycled back through the reverb, DELAY, etc.  You can still modulate some of the parameter controls while it’s in that ‘frozen state’ (using SIZE as an obvious example).

    • #142182

      Here’s something to experiment with.  DELAY at maximum, reverb at minimum, plenty of LOW-, HIGH-, and MID-DECAY.  The pitch shifters mirror perfect 4ths, and PITCH-DECAY loops everything around at 100.


      HotSwitch programming: Switch LOW-, HIGH-, and MID-DECAY to 0.  That leaves a touch of ambient reverb (nothing else).


      The expression pedal here sweeps through the narrow range of PITCH-DECAY: 100, PITCH: FREEZE, and PITCH+VERB: FRZ.  One cool performance technique is to adjust the upper range to ‘just barely’ on PITCH+VERB: FRZ .  Then you can use the majority of the pedal travel between PITCH-DECAY: 100 and PITCH: FREEZE.  Only the top 5-10% of the expression pedal will kick in PITCH+VERB: FRZ.  Makes it easy to selectively add to (and edit) the ‘frozen infinite’ background.


    • #142187

      Brock, many thanks for your reply. From my early messing with this algo I’ve picked up it’s more complex – thanks for the full explanation!

    • #142189
      Eventide Staff

      Ok, so the INF and FREEZE stuff showed up in Space around version 4.  I couldn't find the version 4 release notes on our new website, but I was able to dig them up from the old one.  This little official blurb describes what the meanings are for Shimmer and is in a nutshell what brock was describing (hope it helps): 

      "Shimmer: PITCH FREEZE and PTCH+VRB FRZ on the FxMix knob. PITCH FREEZE locks out the pitch shifters, but feeds the

      reverb, allowing you to freeze the Shimmer pitch climb at opportune times. PTCH+VRB FREEZE freezes everything, pitch and

      reverb for dry soloing on top of the frozen reverb."


      For deeper reference, the general algorithmic structure of Shimmer is this:


                                                   |                                                                                                       |

                                   Inputs –(+) -> Reverb -> Pitchsifters -> EQ Decays and Pitch Decay –>



      > Outputs


      The freezing generally cancels out any decay and throws the feedback loop gain to 1 (infinite decay) and quits feeding the input of the feedback loop.  While the pitch shifter is running though, it doesn't actually go infinite b/c the pitchshifter is eventually shifting energy out fo the audio range, so the loop dies out.  That's why we have two types of freeze.  You might just want to freeze that pitch climb shimmery sound but still have reverb, or you might want to lock out the pad-like reverb sound completely and solo over it, etc.  

    • #142211

      thanks for the additional info!

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