Instruō - dåpf Overview

This video is long... But the second half is very much optional expansion and deep dive into some theory of all-pass filters.
The first few examples are much quicker, more practical examples of dåpf patched.

Please also check out an amazing series of patch examples from the one and only DivKid:
   • Wow! I didn't know All Pass Filters c...  

Thanks for watching :)
~Jason

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Introducing dåpf, the first dedicated effects processor in the Instruō product line. The Instruō dåpf is a set of two analogue all-pass filters.

You might be asking yourself, “What is the point of a filter that passes everything?” All-pass filters don’t actually attenuate frequency amplitudes directly, but rather alter the phase relationship of frequencies across the spectrum. All-pass filter stages appear in the vast majority of voltage-controlled filter topologies as well as serving as a core building block within DSP.

The normalled I/O of dåpf allows for cascaded or independent use of the two all-pass filter circuits, offering everything from classic phase-shifting to psychoacoustic stereo enhancement and synthetic Doppler effect.

• Two parallel all-pass filters
• Independent attenuverters for voltage control
• 1-Pole/2-Pole configuration for left channel
• Cascaded normalisation
• Global 1 volt per octave tracking

00:00:00 Instruōduction
00:03:24 Overview | Stereo Enhancement
00:04:19 Stereo Enhancement - Subtractive patch sound source
00:04:55 Stereo Enhancement - Traditional stereo panning
00:06:13 Stereo Enhancement - Spectrally transparent waveshaping
00:07:22 Stereo Enhancement - dåpf inputs/outputs
00:09:42 Stereo Enhancement - Controls and CV inputs
00:10:14 Stereo Enhancement - 6dB/12dB pole switch
00:11:18 Stereo Enhancement - Mono to Stereo patching
00:15:41 Stereo Enhancement - Static phase shift
00:17:32 Stereo Enhancement - Level 1: modulation
00:19:40 Stereo Enhancement - Level 2: modulation + waveshaping
00:25:02 Stereo Enhancement - Level 3: modulation + timbre
00:27:50 Vibrato Everything
00:28:17 Vibrato Everything - What is vibrato?
00:29:35 Vibrato Everything - Non-FM vibrato
00:30:22 Vibrato Everything - (tangent: sine phase)
00:31:34 Vibrato Everything - (tangent: sine spatialisation)
00:32:37 Vibrato Everything - Non-FM vibrato (sine wave)
00:34:11 Vibrato Everything - Non-FM vibrato (sawtooth wave)
00:38:42 Vibrato Everything - Non-FM vibrato (complex audio)
00:40:46 Vibrato Everything - Non-FM... FM? ...PM! (Phase Modulation)
00:43:47 Feedback Processing |"Doppler"
00:44:33 Feedback Processing |"Doppler" - Lúbadh feedback patch
00:46:38 Feedback Processing |"Doppler" - Doppler shift description
00:48:08 Feedback Processing |"Doppler" - Doppler dåpf 1pole/2-pole
00:49:20 Feedback Processing |"Doppler" - Doppler dåpf 3-pole/-4pole
00:51:28 Feedback Processing |"Doppler" - Doppler dåpf in stereo!
00:52:02 Feedback Processing |"Doppler" - Delay feedback
00:54:54 Feedback Processing |"Doppler" - Audio rate modulation
00:56:32 Building a phaser - Deep dive into all-pass filters
00:58:44 Building a phaser - Phase shift of a fundamental
00:59:41 Building a phaser - Quadrature: sine | cosine
01:00:43 Building a phaser - Drawing perfect circles
01:01:41 Building a phaser - Drawing (non-)perfect circles
01:02:16 Building a phaser - Frequency dependent phase shift
01:04:22 Building a phaser - 1V/octave tracking
01:07:40 Building a phaser - More than one sine wave
01:08:58 Building a phaser - The harmonic overtone series
01:10:19 Building a phaser - Sawtooth wave low-pass filtered (reference)
01:11:15 Building a phaser - Phase shifting harmonic overtones
01:15:42 Building a phaser - Inside a phaser
01:18:00 Building a phaser - Stereo Phaser
01:22:19 Building a phaser - uPhaser Befaco FXBoy
01:23:46 Building filters - Any-pass filter?
01:25:05 Building filters - RC low-pass filter
01:26:03 Building filters - Spectral cancellation principles
01:28:35 Building filters - APF to LPF
01:30:10 Building filters - APF to HPF
01:32:03 Building filters - Parallel dual all-pass filters
01:37:41 Building filters - Resonant filters