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Block - Low-Pass Gate 1.0

Combination VCA and LPF for West-Coast Percussive goodness

 (13 Votes)
1.0 (Updated 5 years ago)
2.9MB
September 27, 2015
Reaktor 6
Sound Processor Modulation VCA Effect Filter Drum Voice

DESCRIPTION

This is the 11th Block in Michael Hetrick's "Euro Reakt" series. A Low-Pass Gate is an effect that combines a low-pass filter with a voltage controlled amplifier (VCA). This effect is frequently used to make physical sounding percussion tones.

Low-Pass Gates play an extremely important role in West-coast style synthesis. These were originally made popular in Buchla synthesizers, and have been explored by modern module makers like Make Noise, Wiard/Malekko, SSF, Mutable Instruments, and more.

Most analog low-pass gates are based on opto-isolators, also known as "vactrols". A vactrol is an LED and a light sensor wrapped in a light-proof case. The vactrol effectively acts as an interpolator for modulation inputs, imparting a fast attack time and slow, rubbery decay. In typical usage, a low-pass gate will be modulated using a gate or trigger. The "vactrol" for this digital low-pass gate is implemented from research found in this paper: http://dafx13.nuim.ie/papers/44.dafx2013_submission_56.pdf For builders, it has been conveniently packaged as a reusable macro.

The vactrol's output controls the amplitude of the VCA and/or the cutoff of the low-pass filter (determined by setting the LPG's mode to VCA, LP, or BOTH). If you would like to hear some sound examples, check out the included ensemble for patching ideas!

Panel Controls:
OFFSET - Adds bias to the vactrol, leaving it partially open.
DAMP - Controls the decay time of the vactrol.
RES - The resonance of the low-pass filter. Only audible in LP or BOTH mode.
MODE - Choose between VCA (amplifier only), LP (filter only), or BOTH.
LIN/EXP - Controls the modulation curve for the VCA and filter cutoff.
ENV - Controls the depth of modulation that the vactrol imparts on the VCA and filter.

IN - Audio Input
VAC - Vactrol Input. Typically, you would hit this with a gate or trigger, but you can place any modulation source in here. The source will be modified to have a rapid attack and slow, rubbery decay.
PING - Converts a modulation source to a trigger.
DIRECT - Modulation input. Skips the vactrol and modifies the VCA/Filter directly without interpolation.

OUT - Main Output, post-filter and VCA.
ENV - Output's the vactrol's control signal.

COMMENTS  (14)

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Artem Moroz
1 month ago
Thank You VerY MUCH!!!
Simon Sherbourne
5 years ago
This is really great, thank you.
Bryce Upright
5 years ago
Great idea Andreas Schinagl....I could also see the vactrol here being used in other Blocks to get that "gummy" response.
Diego torelli ghiddini
5 years ago
Lovely creation, i'm on building blocks structure, it's not so simple for me but is a lot of fun... my goals is integrate mt Eruro with blocks..
ae ae
5 years ago
Andreas Schinagl - You or anyone else may submit your requests here: https://www.native-instruments.com/forum/threads/blocks-requests.261656/ Value the kindness all Builder have to share their works of art with the rest of the community for " free ". We should feel fortunate that any builder is sharing their creations with us and we should be grateful and say Thank you and show our appreciation for it. The builders should not be seen as servants . The builders are the real rock stars here without them you or anyone else would be stuck with stock factory blocks and left having to learn how to build for themselves. Builders are not running a candy store for some who feel entitled to be receiving new blocks and updated blocks around the clock. Once again Thanks Michael and all the builders for sharing things with us for " free " we are grateful and value any modules and updates which appear.
Andreas Schinagl
5 years ago
Hi Michael, any chance that you build a A-101-1 (Vatrol based steiner filter)? The Doepfer A-101-1 Steiner filter is one of my all time favourite filters.
Jason Leiter
5 years ago
Bah, I meant to type that last thing for your wavefolder, I see you did that here. Nevermind that last comment.
Jason Leiter
5 years ago
My one request would be to copy paste what you wrote here for Panel Controls: Into the info for the block, for those of us who aren't familiar with the real world counterpart.
Jason Leiter
5 years ago
I really like this one. I monkeyed around with the filter types under the hood and got some cool stuff as well.
Bryce Upright
5 years ago
The Vactrol is EXTREMELY convincing! Excellent work.
Bryce Upright
5 years ago
Actually this sound really good. Thanks Michael....your Euro Reakt series has been great. It's great to see where you and other developers are taking Blocks
Bryce Upright
5 years ago
Does it have a vactrol :-P
Michael Hetrick
5 years ago
Thanks! I'm really glad that you like this one. I spent a bit more time on this one than usual. I use LPGs all the time in my own music, and wanted to make sure that I liked the feel of this. One small bonus feature is that the filter is separated from the rest of the Core code in a way that makes it easy for modifications. If you don't like the sound of the 2P Sallen-Key that I picked, it's easy to delete it, drop in another filter from the Core library, and just reconnect the wires.
ae ae
5 years ago
Thank you Michael , another black beauty !
now