Meta Morph : How to Patch?, Tips n' Tricks, Questions?

Share your patching techniques… show us how you do things? or vcv tips related to using Meta Morph.
also, feel free to include small patches that demonstrate these ideas.

AND… of course, you can ask questions here?
want to know how to implement octave switching or something else you know from EigenD.
then ask here!

we can discuss how it can be done with what we have…
if not, it might provoke ideas on new modules for Meta Morph, or how existing modules could be modified to accommodate this functionality.

Meta Morph is very much part of the VCV ecosystem, so you can use all the tips n’ tricks that every other vcv users use.

I’d highly recommend Omri Cohen’s YouTube channel for getting started, finding new modules and also learning advance VCV techniques… he is THE star of VCV!

the official VCV Rack forum is a great place to ask general questions about VCV Rack -

if you have a problem when installing Meta Morph for the first time, please see my troubleshooting topic

the Meta Morph wiki, also has a tips n’ tricks topics

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Avoiding clicks

a simple voice patch will do something like
Key → (key) Scaler Key (v/oct) → (v/oct) Oscillator → VCA
Z → VCA → Output
this is fine for testing, but you may notice that you get some clicks when you initially press a key - it really spoils the sound.

reason: on the Eigenharp Z is very sensitive and will jump from 0 virtually instantaneously, and some audio discontinuities, if you drive a VCA directly.
solution: use a slew limiter (vcv : PROCESS module does the trick) to slightly smooth the values.
even a tiny slew, like 1-2ms will make a huge difference, and still feel responsive.

btw: this same slew is also a really nice way to get more ‘pad’ like sounds, without requiring an envelope.

its possible to get similar artefacts from modulate with x/y but its not as common -but can be worth trying, if you feel like the sound has some aliasing etc.
(besides, adding slews can actually be a nice sound design tool anyway)


sample n’ hold (S&H)

(and its relative … T&H)

a popular saying in the modular world is: ‘You can never have enough VCAs’
(why is another topic/post :))

BUT, here you can add… you can never have enough S&Hs!

vcv tip:
the vcvrack PROCESS module is great for this, though there are many others.

in the modular world all change are ‘instantaneous’, voltages change immediately… unlike traditional synths (and midi) where most things are tied to a note on/off event.

but sometimes in modular, you want to have changes ‘synchronise’ to events, be that a clock or a key press - and this is where S&H come in, basically, if you want to hold off a change based on key events then use z/gate into the trig of a S&H.
there are numerous variations on this… but just remember, if you don’t want things sliding around S&H is your friend.

Ive noticed in my early playing with MM (and also from the EA)
S&H are even more common with Eigenharps, the reason is, we are using live input … we are the expression.
whereas most modular videos will either be using sequencers (which naturally sync changes’, or midi and so either sync’d envelopes or lfos.

another related use-case is T&H (track n’ hold).
where S&H freezes a value on a trig , track and hold will change a value only when a gate is high.

e.g - use S&H to freeze voltage when you press a key, use T&H to allow a value to only change when you are holding down a key.



this is a very important topic for cpu load.
you can use Split and Switch to reduce polyphony and so reduce cpu load.

in VCV Rack a module that is using 16 note polyphony, could be using 16x (or even more) cpu load than when using 1 voice.

so imagine a subtractive voice

VCO → VCF → VCA → Delay

using 16 voices, means its like having 16 of each of these modules.
and these are present for every split and even a switch that is inactive !

so reduce the poly count to what you need.
also consider moving FX to be a send effect and/or convert to mono (via SUM module)

your CPU will thank you !

(this is particularly important for patches which have multiple synth voices etc)

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Have been playing around with sample and holds in order to implement transpose keys - pressing one button tunes the instrument down, another up - several presses result in several retunings.
Now I am trying to find a way to keep the pitch of keys that were already pressed when a transpose key is pressed. But new keys should already sound in the higher/lower register.
So one could e.g. tune down, play a bass note, keep it pressed, tune up and then play some high melody on top.
I am almost there, keys are keeping their pitch when being pressed. But a transposition change only comes into effect when all keys are released.

Here two variants - one with the standard sample and hold
Octaves2.vcv (2.4 KB)

and one with the poly sample and hold from Bogaudio
Octaves3.vcv (2.5 KB)

(also tried a few other S&Hs, they all seem to show the same behavior).

Has anybody an idea how this would be possible?

Edit: Here a screenshot (of a further simplified version):

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use my octave module into S&H, here is a pico example

note: you need to ensure octave/s&h is polyphonic, polymult here.
(but given we only want 0v, you could also use vca from Z with vca set to 0%)

btw: probably for simple examples, screenshots work better? so we dont have to run up vcv to see what you are doing … aids discussion for everyone.
for more complex, patches uploads may be better…
though, I guess, its probably best to condense the problem anyway… as few will have time to dig into complex patches.
… just thinking aloud on best way to help?


Thanks, have rebuilt your proposal. It is showing the same behavior for me.

  • Press two keys on the Pico
  • press a mode key to tune up or down
  • release one of the two keys, keep the other one pressed
  • press down the other key again

Expectation: The new key should now have the new pitch already while the old key keeps the old one
Behavior: The new key also still has the old pitch. The new pitch is only taken into consideration when all keys are released first.

Good idea regarding screenshots, might make it easier to follow by just browsing through.

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that’s not what im getting here… it works as expect here…
existing keys keep same pitch, new keys get new pitch.

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Works now! Sorry, overlooked the channel knob on the polymult module, was still set to 1…


yeah, actually using a vca set to zero is better…
z → vca (0) → octave : in

( I didnt change as was too lazy to take another screenshot n’ upload :laughing: )

reason being this will mean the polyphony follows what is set upstream (eigenharp/split etc)
either works… but this is slightly more ‘efficient’


Hi there,

This is a basic setup question, not sure if this the right place to post.

I’ve installed the meta morph package from your link and am loading up some of the simple presets but I am getting no visual feedback on the Eigenharp or in VCV rack, and no sound from VCV rack. From watching your tutorials I assume that something should happen with any of your presets without any further configuration, is that correct?

Using an M2 Mac with Ventura 13.6.3 with a Pico and VCV Rack Free 2.4.1. Any basic troubleshooting steps you suggest?


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You have to select your audio device in the audio module. Before that the clock for the other modules isn’t running either.
No audio selected (the default for any loaded preset):

An audio output selected:


I’ve added a note to the getting started topic to highlight this, as its easy to forget .
(even though my patches do have a NOTE pointing this out)
but, its a good opportunity to dig in a bit.

edit : Ive also added a new troubleshooting topic on the wiki, which covers this and a few other possible issues new users may face.

AUDIO module - set it correctly !

tl;dr; most patches will have an (vcvrack) AUDIO modules which is used to interface to your audio interface - this MUST be set correctly for your Eigenharp to work!

the reason for this is the processing of the Eigenharp messages is at sample rate sync’d to your audio interface clock, done via the AUDIO interface.
if this is incorrectly configured, you will see NO activity.

this is the most common issue users will face when loading a patch from someone else

lets explore this in a little more detail… as its kind of interesting

no audio module … it works!

IF you create an empty patch, without any AUDIO interface module, the Eigenharp WIIL work.
why, you said above it needs the audio clock to work?
because, in this special case… VCV rack creates an internal clock as a substitute.
however, this internal clock is disabled as soon as you create an AUDIO module !

loading someone else’s (incl demos) patches

this leads to the issue we see when loading someone else’s patch.
they will have an AUDIO module, but it will be save pointing to their audio interface which will not be present/valid - so you end up with no audio clock until you re-configure it.

really, vcv rack should default to the system’s default audio interface, however it does not.

multiple AUDIO modules, and master

what happens if you have multiple AUDIO modules pointing to different audio interfaces?
by default, the first AUDIO module you add to the patch will be the master , and this will be used as the audio clock. any other will be a slave and will sync to this clock.
you can change this on the AUDIO module menu, and set any other module to be the master, and so be the primary audio clock.

as I said TL;DR…if you ever load a 3rd party patch, the first thing to do is to set the audio interface on the AUDIO module


6 posts were split to a new topic: Pico not connecting?