Filter overdrive is bypassed in neigbor routing

Elektron Gear Analog Keys/Four
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I’m still trying to fall in love with the A4 and neighbor tracks were one of my final “deep” features (in fact there are about 5 posts ever on it) to fully explore to achieve truly interesting sounds.

While doing that I realised to my dismay that filter overdrive isn’t carried to the neighbour. This makes no sense since it’s supposed to sit between F1 and F2 and destroys the possibility of layering and filtering existing distortion which would open up some very interesting resonant and dissonant textures.

It also makes me question the analog signal path if this can be (digitally?) bypassed…

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I’m wondering about this too, have you upgraded to the new OS?

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I’m not sure which device or OS you’re running but I can assure you it works on the Mk1(1.24) and I doubt it is one of those areas where the OS tinkering might result in a bug, but who knows

be sure that you understand how NEI works - you need to be constantly sounding the feeding voice, its frequency is derived from its own track, not the track with the nei routing on osc2 - but the overdrive is certainly feeding into the next track when I try it

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Unless I’m misunderstanding you, then that’s incorrect. You can trigger T1 just fine from T2, without anything triggered on T1 itself. And both oscs and both filters on T1 are effectual to the sound coming through to T2. Except filter overdrive.

In other words, overdrive behaves like a send FX in this scenario. In fact, I wonder if that is exactly what it is…

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There are midi configurations and poly routing configurations which will permit activation of the preceding voice, but in the latter case the poly settings may mean there is scope for ambiguity about the sound in the higher track

either way, we could be into the realms of patch/kit/poly issues particular to a given config, but in terms of the position of the routing (post MMF, which is after the Ladder/drive) it’s certainly coming through to the next track affected by the overdrive when i play with it - that’s not to say there are not ways to bug it out

if you can present the minimum case to replicate the issue in its simplest form (fewest steps from clear kit) then perhaps you’ll get people confirming - so there are potentially cases where it doesn’t work but it’s not accurate to suggest it’s bypassed in a general sense, it works in a simple test where T1 and T2 are droning (but T1’s audio is only coming via T2)

If you clear the kit and set T2 to NEI with default settings elsewhere, T1 won’t be triggered by playing T2 just because of the setting change on T2 osc2

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Nope, nothing to do with poly or unison/use trk sounds.

Start a blank project/kit (no poly settings) and leave T1 on default settings. On T2, turn off osc 1, then put osc 2 in NEI and bring up the volume. Play any note on T2 alone. You will hear T1.

To confirm, input a pattern on T2, then start tweaking the osc and filter settings on T1. All of this will have an effect except overdrive.

The way you’ve described how to use NEI is not “true” neighbour e.g. serial routing. It’s really more like another form of unison because you are still hearing T1 being sent directly to the master outs. And you aren’t hearing T1’s overdrive through T2. You are hearing the overdrive on T1 alone.

All of this begs the question, what exactly is the routing at work? Overdrive probably isn’t a send FX like I said. If I had to guess it’s actually tied to the amp stage. That could also explain why F2 can’t do nice growly Moogy bass. The overdrive might be being applied after F2 - not between F1 and F2.

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I can assure you, as already mentioned above, this was not the case I described - I was passing T1 only via T2’s filter - I could actively filter out the audible modulation of T1’s overdrive by using the T2 filter

There was no unison or T1 at mains, I was simply passing the overdriven filter thru the NEI injection point on T2 and it was behaving without obvious issue

However, I partially confused the picture with something I said above wrt activating T1 - I was probably confusing the point that T2 will not affect the OSC pitch of T1 with the need to be triggering T1 somehow and as this is tapped off before the amp then it explains our different viewpoint, I hadn’t helped that part of it by mixing up these ideas into an incorrect thought

but this error also points to the source of the (probable) bug as I am able to replicate your experience whilst I am also able to illustrate that I was indeed hearing the overdriven filter on T1 coming through to T2 … to be clear, the amp level on T1 was all the way down

When the oscillators of T1 are modulated from your vanilla state you’ll hear that modulation, if you swap the modulation destination to be overdrive you will not hear the overdrive modulated - this was not my former experience

The only difference was that I was triggering the T1 track (spuriously admittedly, but fortuitously as it accounts for the different experiences documented)

So even though the LFO is running free and whilst the amp level is down it seems to make a difference if the T1 track has been triggered because the overdrive modulation will be audible and it is entirely filterable via T2

I didn’t check if triggering remedied static adjustment of T1’s filter overdrive setting but I concur that in the base test there is no change when the value is manually adjusted, but due to the manner with which I was modulating (inc trigger, TRC 1st Len Inf) this parameter I was able to pass T1 Filt OD through T2

So it does indeed raise some questions about why this odd discrepancy exists, whether it’s a bug or a consequence of the way the overdrive is implemented, but I can’t see why triggering the T1 voice should make a difference with only a free lfo running (which plays fine for the pitch sans trig) - it sounds like there’s a bug in there somewhere that’s possibly never been spotted and it may only make sense to the devs

it might be worth testing if parameter locks of the overdrive setting on T1 are passed through, but i agree that manual settings are not reflected at T2 - you should ask support to confirm if this is a bug as it’s clearly possible, but not without added modulation

As I said, I’m on MK1 1.24

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@Dusk1983 You’re pretty much right, although I did find that the T1 overdrive circuit is affecting what I hear on T2 but only when there is a non-zero amp envelope level on T1. This is true even if the track level and amp level of T1 is set to zero. As @avantronica mentioned, no other modulation sources targeting F1 overdrive or manual changing of the parameter seem to have any effect unless T1 amp env is non-zero. I’ve long suspected based on the synth’s behavior that the amp, the oscillator levels including the feedback oscillator, and the overdrive circuit are all one functional block. I think that the block diagram in the user manual is misleading here, as its probably meant to provide a familiar picture of how you can expect the unit to behave rather than providing a high-level schematic that corresponds 1-to-1 with the circuit topology. Anyway, I hadn’t noticed this phenomenon until your post since I always use the copy and paste track shortcuts when working in neighbor mode (see my old post on using neighbor mode for vocal formants) but i’m glad to now know about this little quirk. Thanks for bringing it up!

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From memory, to avoid confusion, here is what I tweaked from the vanilla state

T1 Amp Level = 0
T2 O1 = Ground
T2 O2 = Nei / Level 100
Play T2
Tweak T1 F1 OD
Play T2 - OD changes are not reflected (yet)

Modulate T1 OSC with an LFO - this is audible through T2
Swap Modulation Destination to Filter OD - this is not audible (yet)

Trigger the T1 seq with a Trigger on 1 = TRC 1st / Note Len = Inf (this is what I did first in my first test)

Play T2 - OD changes are now audible and may be filtered by T2 filter

So indeed, activating the ‘inaudible’ amp envelope is enough to allow the T1 Filter Overdrive to be heard via T2, this may be simply a consequence of the routing and somewhat less bug and more nuance

A simple way to illustrate is to change the note length of T1 trig to 8, then you’ll hear the Filter OD pass through at T2 for half a bar and vanish for the rest, so as mentioned above a non-zero amp envelope is key here to activating the overdrive

It would be interesting to establish if it’s the same for the Mk2 before someone runs this past support

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Really interesting posts, thanks @avantronica @helloliamdaly! I will try the inaudible amp envelope when I get home. It’s slightly inconvenient having to duplicate patterns between tracks, but not a deal breaker. Plus, I wonder if “use track sounds” can be deployed instead…

I was also going to try disabling voice routing for T1 in the global settings. There are so many configurations possible with this synth.

But perhaps @Olle or @Ess could chime in on the circuit topology at work here. Why would overdrive be tied to the amp stage and if so does the amp level also affect the drive behaviour? I agree it would also be good to hear from mk2 users.

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