Pitch Change — effect atlas¶

2 effects · 204 captures. Dual-voice pitch shifters. These are time-varying by design and the least well-served by the current probes — see test T8.

Part of the Motif ES effects teardown; the method and the cross-effect findings are in the main analysis (notebook).

How to read a card¶

Each effect gets one card, then a written breakdown.

Header band. The effect's name, category, how many recordings exist, and a one-sentence summary written from the measurements.
Tiles. The handful of numbers that matter most for this type of effect, at default settings. A dash means the value could not be measured, and the small caption says why.
The knob console. One knob per control. Click a knob to select it and move the slider under the knobs to turn it. A knob's ring is its own travel, coloured stretch by stretch: green where turning it barely changes the sound, red where a small turn changes it a lot, grey where nothing measurable happens. A knob outlined in cyan was also recorded together with the selected one, and its ring changes as the slider moves; every other ring shows that knob with the rest at their defaults. Controls that showed no measurable change at all are listed under the console, not drawn.
What each knob does. One bar per control, longest first. Bar length is the size of the change the knob makes, in multiples of the smallest change that matters in practice (1 dB of level, 20% of decay time, 10% of LFO rate…), on a log scale. Colour says what kind of change. ◆ marks readings taken with a test sound designed for that knob. Grey dots are knobs that did nothing with the other controls at default.
Signature panel. The view that best explains this kind of effect: decay curves for a reverb, echo taps for a delay, the input/output curve for a compressor, harmonics against input level for a distortion, the LFO for a modulation effect.
Knob × frequency. Each row is one knob at one tested setting; red means louder than default at that frequency, blue quieter. Modulation effects get a what the knobs touch matrix instead, because a running LFO has no single frequency response.
Stereo. How the left and right inputs reach the outputs.

The breakdown under each card notes the structure the measurements reveal, flags caveats, and names the tests in TESTS_NEEDED.md that would complete the picture. Below it, every knob is charted with the range tested and what it does; hover a bar for the detail.

Show code

In [1]:

import warnings; warnings.filterwarnings("ignore")
import sys; sys.path.insert(0, "..")
import os; os.chdir("..")                   # the cache lives in the project root
import matplotlib.pyplot as plt
from IPython.display import HTML, Markdown, display
import load, knobs, cards, plots, iviz, gapfill, knobviz, vizstyle as V
V.setup()
from matplotlib_inline.backend_inline import set_matplotlib_formats
set_matplotlib_formats("svg")           # figures embed as vector, not PNG
display(iviz.page_css())
df, curves = load.load()
noise = knobs.noise_table(df, curves)
g = gapfill.load()

def show(fig):
    display(fig)
    plt.close(fig)

def show_card(effect):
    show(cards.effect_card(df, curves, effect, noise)[0])

def show_knobs(effect):
    board = knobviz.console(df, curves, effect, noise)
    if board is not None:
        display(board)
    _, main, rh = cards.merged_knobs(df, curves, effect, noise)
    for h in iviz.knob_plots(effect, main, rh):
        display(h)

def show_parts(parts):
    for f, note in parts:           # each chart, then its own explanation directly under it
        f.show()
        display(Markdown(note))

def show_gapfill(effect, stimuli=None, drives_only=False):
    parts = iviz.gf_effect_parts(g, effect, stimuli, drives_only)
    if parts:
        display(Markdown(iviz.GF_INTRO))
    show_parts(parts)

The family at a glance¶

Every effect in the category on the same few numbers, then all of them on one chart — drag the slider to bring one forward, hover for exact values.

Show code

In [2]:

knob_counts = {'Pitch Change 1': (10, 0), 'Pitch Change 2': (10, 0)}
show(cards.family_overview(df, 'Pitch Change', knob_counts, curves))

No description has been provided for this image

Show code

In [3]:

iviz.family_fig(df, curves, 'Pitch Change').show()

Recap. Why: to compare the tone of every effect in the family on one chart. How to read it: each line is one effect's frequency response, centred on its own median; drag the slider to bring one forward, hover for exact values.

Technical explanation. Each effect's frequency response at the capture baseline — how much each frequency is boosted or cut on its way through — measured by log-sweep deconvolution, smoothed to 1/6 octave, averaged over repeat captures, and shifted to its own median so the chart compares tone shape, not loudness. Drag the slider to bring one effect forward. The chart below this text reads each curve off as three numbers: its peak, the range within 6 dB of the peak, and the span from peak to deepest cut.

Less reliable in detail (repeat captures differ by over 3 dB, usually a running LFO): Pitch Change 1, Pitch Change 2. These effects move while they are measured, so each curve is one snapshot of a response that sweeps back and forth; read the overall tilt, not individual notches. The LFO maps in the cards and in §14 of the main analysis show the movement itself. Not shown: level (each curve is centred on its own median), anything that changes over time.

Plain explanation: this is the effect's tone — which parts of the sound it makes louder or quieter. Because these effects sweep constantly, think of each line as a single frame of a moving picture.

In other words, the main points:

Most shaping: Pitch Change 2, 21 dB from peak to deepest cut.
Least repeatable in detail (usually a running LFO): Pitch Change 1, Pitch Change 2.

Show code

In [4]:

iviz.tone_bands(df, curves, 'Pitch Change')

Out[4]:

What a shifted note is made of¶

A pitch shifter of this kind cannot return a pure shifted note. These charts show what it returns instead, and read the size of its splice window from it.

Show code

In [5]:

import kinetics, kviz, wviz, rviz
show_parts(kviz.pitch_parts(g))

What it shows. A steady 440 Hz note through each pitch shifter at four Pitch settings, with only the shifted sound returned. Each dot is one spectral line of what came back, placed by how far it is from the pitch that was asked for; bigger dots are stronger lines.

How to read it. One row per setting; the dotted line marks the target pitch. A perfect shifter would put a single dot on that line.

What it found.

Neither effect returns a single note.
Each returns a cluster of evenly spaced lines around the target: the power-weighted centre of the cluster is within 111 cents of the setting at every step (about a semitone at worst, at two octaves down), taking one semitone per step either side of raw 64.
The spacing is small for a small shift and wide for a large one, which is why a two-semitone shift sounds like a slow flutter and a two-octave shift like a buzz.
Settings below raw 40 read the same as raw 40: the range stops at two octaves down (4 takes).

What it shows. The spacing between the lines in each cluster, against the size of the shift. A shifter that plays back a short stretch of delay line at the wrong speed has to jump back each time it runs out; it makes that jump at a rate of |pitch ratio − 1| ÷ window length, and that rate is the spacing between the lines.

How to read it. Size of the shift left to right, line spacing upward. Points on a straight line through the origin mean one fixed window length; the slope gives the length.

What it found.

Pitch Change 1 fits a window of 34.7 ms (about 1532 samples) and Pitch Change 2 one of 27.9 ms (about 1230 samples), with every point within 6% of its line.
The spacing is the same for the 440 Hz note and for the 880 Hz note an octave above (within 0.2 Hz), so it belongs to the effect, not to the note.
The two effects are the same kind of delay-line shifter with different window lengths.
Pitch Change 2's shorter window splices more often at any given shift.
Only four distinct shifts were recorded per effect, so the window lengths are good to a few percent.

What it shows. A click every 40 ms through each pitch shifter at four Pitch settings. Each tick is one click in the output; the grey row at the top is the input. The first tick of each row is lined up at zero.

How to read it. A shifter that raises pitch plays its delay line back faster, so clicks come out closer together than they went in, until it runs out and has to jump back; one that lowers pitch spreads them out and repeats or drops some. Evenly spaced ticks are the playback; an odd gap or a doubled tick is a splice.

What it found.

Clicks per second coming out, for 25 going in: Pitch Change 1 at −24 semitones 8 (25 × the pitch ratio is 6); Pitch Change 1 at −20 semitones 9 (25 × the pitch ratio is 8); Pitch Change 1 at +2 semitones 34 (25 × the pitch ratio is 28); Pitch Change 1 at +24 semitones 93 (25 × the pitch ratio is 100); Pitch Change 2 at −24 semitones 8 (25 × the pitch ratio is 6); Pitch Change 2 at −20 semitones 2 (25 × the pitch ratio is 8); Pitch Change 2 at +2 semitones 32 (25 × the pitch ratio is 28); Pitch Change 2 at +24 semitones 109 (25 × the pitch ratio is 100).
The count out follows the pitch ratio: shifted up two octaves, each click in comes out about four times; shifted down, most clicks are dropped.
Between splices the ticks are evenly spaced at the new speed.
This is why a pitch shifter of this kind smears drums: one hit in can be several hits out, or none.

Pitch Change 1¶

Show code

In [6]:

show_card('Pitch Change 1')

Pitch Change 1: what the measurements say¶

Recap. A modulation effect with 10 tested controls, 10 of which measurably change the sound. Beyond mix and level, the biggest lever is Initial Delay: echo tail T30 8.83 → 0.00 s. Measured with 102 captures: 51 on the main sweep + tone probe (one control at a time), 23 on matched probes (spectralSweep ×13, impulseTail ×5, stereoRouting ×5), 28 two-control pairs.

Technical explanation. At default settings: output -30.5 dBFS RMS (crest 14.2 dB); stereo width 0.17, L/R correlation +0.94; spectral tilt +0.24 dB/octave; 97% of the impulse response's energy in its first 5 ms; harmonics H2 -54 dB, H3 -61 dB re the linear response.

Two-control pairs captured: Initial Delay×Feedback Level, Initial Delay×Pan 1, Initial Delay×Pan 2, Initial Delay×Pitch, Pan 1×Pan 2, Pitch×Pan 1, Pitch×Pan 2 (interaction analysis in the main notebook).

Caveats:

the LFO runs during the sweep, so the frequency-response features are averages over LFO phase, not a fixed response
some long settings decay more slowly than the recording allows; their T30 is a lower bound

Plain explanation: The control to reach for first is Initial Delay: echo tail T30 8.83 → 0.00 s. After that, Pitch, Pan 1 and Pan 2 make the next biggest differences. DryWet, Output Level 2 and Output Level 1 set how much of the effect you hear and how loud it is. At default it has a moderate stereo spread.

In other words, the main points:

10 of 10 tested controls measurably change the sound.
Biggest lever beyond mix and level: Initial Delay, 42.7× the smallest change that matters (echo tail T30 8.83 → 0.00 s).
At default: stereo width 0.17, output -30.5 dBFS RMS.
Main caveat: the LFO runs during the sweep, so the frequency-response features are averages over LFO phase, not a fixed response.
Still to measure: T1, T4, T6, T7 (see TESTS_NEEDED.md).

Show code

In [7]:

show_knobs('Pitch Change 1')

barely changes the soundchanges it a lot■no measurable change

Click a knob to select it, then move the slider to turn it. A ring is that knob's own travel: green stretches barely change the sound, red stretches change it a lot. Rings show each knob with the others at their defaults; a knob outlined in cyan was also recorded together with the selected one, and its ring follows the slider.

Gap Fill: each control in physical units¶

Every control stepped on a probe matched to what it does (17 steps for time and rate controls, 9 for the rest), read as the physical quantity it sets: how far a delay tap moves, level or treble lost per repeat, LFO rate and pitch swing, gate length, THD, intermodulation, compressor ratio, knee, attack and release, and where a gate opens and closes. Times are read inside one capture (channel against channel) because Gap Fill runs fully wet and file starts wander by about ±50 ms.

Show code

In [8]:

show_gapfill('Pitch Change 1')

How to read these charts. Each chart is one control. Left to right is the control's raw value as sent to the Motif (low to high setting); the height of the line is the physical quantity that control sets, measured from the recording. The title names the control, then the test signal used.

Feedback-Level · sweepTail. Played: a sweep followed by silence. The line is dB per repeat: how much quieter each repeat is than the one before; closer to 0 means more repeats; here it goes from -0.342 at raw 0 to -0.256 at raw 127, peaking at 1.07, dipping to -0.841.

Fine-1 · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 20.8 at raw 0 to 20.9 at raw 114, dipping to 3.86.

Fine-2 · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 20.9 at raw 0 to 20.9 at raw 114, dipping to 3.86.

Initial-Delay · sweepTail. Played: a sweep followed by silence. The line is s T30: the reverb decay time (extrapolated to 60 dB of decay); here it goes from 0.546 at raw 0 to 0.513 at raw 127, peaking at 0.634.

Pan-1 · stereoRouting. Played: bursts sent left only, right only, both in phase and both out of phase. The line is dB L/R isolation: how well left and right are kept apart; higher means less bleed; here it goes from -4.11 at raw 0 to -7.38 at raw 127, peaking at -0.382.

Pan-2 · stereoRouting. Played: bursts sent left only, right only, both in phase and both out of phase. The line is dB L/R isolation: how well left and right are kept apart; higher means less bleed; here it goes from -7.93 at raw 0 to -7.38 at raw 127, peaking at -0.382.

Pitch · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 24.4 at raw 0 to 18.7 at raw 88, peaking at 33.6, dipping to 0.

Pitch Change 2¶

Show code

In [9]:

show_card('Pitch Change 2')

Pitch Change 2: what the measurements say¶

Recap. A modulation effect with 10 tested controls, 10 of which measurably change the sound. Beyond mix and level, the biggest lever is Initial Delay: echo tail T30 8.80 → 0.01 s. Measured with 102 captures: 51 on the main sweep + tone probe (one control at a time), 23 on matched probes (spectralSweep ×13, impulseTail ×5, stereoRouting ×5), 28 two-control pairs.

Technical explanation. At default settings: output -29.9 dBFS RMS (crest 14.1 dB); stereo width 0.17, L/R correlation +0.95; spectral tilt +0.36 dB/octave; 97% of the impulse response's energy in its first 5 ms; harmonics H2 -51 dB, H3 -59 dB re the linear response.

Two-control pairs captured: Initial Delay×Feedback Level, Initial Delay×Pan 1, Initial Delay×Pan 2, Initial Delay×Pitch, Pan 1×Pitch, Pan 2×Pan 1, Pan 2×Pitch (interaction analysis in the main notebook).

Caveats:

the LFO runs during the sweep, so the frequency-response features are averages over LFO phase, not a fixed response
some long settings decay more slowly than the recording allows; their T30 is a lower bound

Plain explanation: The control to reach for first is Initial Delay: echo tail T30 8.80 → 0.01 s. After that, Pan 2, Pan 1 and Pitch make the next biggest differences. Output Level 2, DryWet and Output Level 1 set how much of the effect you hear and how loud it is. At default it has a moderate stereo spread.

In other words, the main points:

10 of 10 tested controls measurably change the sound.
Biggest lever beyond mix and level: Initial Delay, 39.8× the smallest change that matters (echo tail T30 8.80 → 0.01 s).
At default: stereo width 0.17, output -29.9 dBFS RMS.
Main caveat: the LFO runs during the sweep, so the frequency-response features are averages over LFO phase, not a fixed response.
Still to measure: T1, T4, T6, T7 (see TESTS_NEEDED.md).

Show code

In [10]:

show_knobs('Pitch Change 2')

barely changes the soundchanges it a lot■no measurable change

Gap Fill: each control in physical units¶

Show code

In [11]:

show_gapfill('Pitch Change 2')

Fine-1 · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 7.9 at raw 0 to 7.86 at raw 114, peaking at 24.3.

Fine-2 · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 7.88 at raw 0 to 7.89 at raw 114, peaking at 24.3.

Initial-Delay · sweepTail. Played: a sweep followed by silence. The line is s T30: the reverb decay time (extrapolated to 60 dB of decay); here it goes from 0.475 at raw 0 to 0.463 at raw 127, peaking at 0.495, dipping to 0.38.

Pan-1 · stereoRouting. Played: bursts sent left only, right only, both in phase and both out of phase. The line is dB L/R isolation: how well left and right are kept apart; higher means less bleed; here it goes from -7.93 at raw 0 to -7.38 at raw 127, peaking at -0.382.

Pitch · pureSine. Played: a steady 440 Hz sine. The line is Hz LFO rate: how many times a second the modulation cycles; here it goes from 8.26 at raw 0 to 18.7 at raw 88, peaking at 37.6, dipping to 0.

Revision 36 · 2026-10-15

Revision history

Rev 36 · 2026-10-15: The Distortion drive ladders are re-recorded in the current setup (80 takes) and replace those of 2026-09-28, whose flat-topped waves came from the levels of the setup at the time, not from the effects: with the drive up, each distortion gives a square wave whose tops sag, and its Output Level only scales it.
Rev 35 · 2026-10-12: The main page folds by topic and each family's detail page folds by effect: every section is closed until opened, with one control to open or close them all.
Rev 34 · 2026-10-12: Every sheet: a play button steps through each control's settings; every recorded pair of controls drawn, with whether they simply add or one changes the other; EQ frequency and width controls drawn with their band at full boost. New detailed charts on every board: which controls depend on each other; the EQ bands moving; the ring modulator's pitch against its controls.
Rev 33 · 2026-10-12: Every control on every effect's sheet: all its tested settings overlaid in one cell, and its measured law in physical units where a probe reads one. Misc board: the equalisers' bands at full cut and boost.
Rev 32 · 2026-10-12: Headline findings set apart with larger titles; a note under the three whose graphic shows less than the headline says (Lo-Fi rate, delay feedback, repeats).
Rev 31 · 2026-10-12: Main page: a graphic under each of the eight headline findings (the delay feedback one animated), each with a plain-terms line.
Rev 30 · 2026-10-12: Main page opens with a chart of where every capture went and the central technique in pictures: the sweep, and the spikes the matched filter turns a recording of it into.
Rev 29 · 2026-10-12: Misc board: the ring modulator's carrier pitch against OSC Freq Coarse and Fine, read from the sine takes.
Rev 28 · 2026-10-11: Fifth capture batch in: the Reverb board gains the gap before the reverb starts against Initial Delay, the Chorus and Flanger boards gain the delay length against the delay knob.
Rev 27 · 2026-10-11: Waves: a third page, what the instrument and effect waves measure: the note each one plays, where it starts repeating and how long the loop is, how long it rings, and the harmonics of each pitched wave.
Rev 26 · 2026-10-11: Waves: the instrument and effect tiles now show the opening of the note (its first 8 cycles) instead of the whole take, so the individual waves can be seen.
Rev 25 · 2026-10-11: Waves: a second page for the 955 instrument and effect waves, each drawn as the whole take of one note with one cycle of the sound under it where the wave holds a steady pitch.
Rev 24 · 2026-10-08: Reverb knob pairs recorded (288 takes over the 12 distinct reverbs), so the reverb consoles' rings follow each other too; 799 knob pairs measured in all.
Rev 23 · 2026-10-08: Every family page now opens with a comparison board (one row per effect, shared scales down each column) and control sheets with all tested settings side by side; each family's detailed charts are folded in beneath and the earlier pages are kept as detail pages.
Rev 22 · 2026-10-08: Knob consoles: 2,120 new recordings of knob pairs, so within each effect's four strongest controls every knob's ring now follows every other (679 pairs measured, up from 155). A Waves page shows the 904 drum and percussion waves.
Rev 21 · 2026-10-07: Delay page rebuilt the same way: every delay's echoes side by side, and each control's tested settings next to each other as echo patterns.
Rev 20 · 2026-10-07: Reverb page rebuilt for comparison: one board with every distinct reverb as a row and every measure as a column on a shared scale, then each reverb's controls with all tested settings side by side. The detailed charts are folded in beneath; the earlier page is kept as the detail page. Knob consoles now use a slider for the selected knob, and controls with nothing measurable are listed, not drawn.
Rev 19 · 2026-10-07: A knob console on every effect: each ring shows where along the knob's travel the sound changes, and turning a knob shows how the knobs captured together with it respond.
Rev 18 · 2026-10-07: Reverb taken apart in time: how fast separate reflections merge into a wash; the tail's colour through time; how alike left and right are at each pitch and through the decay; how smooth each tail is against noise of the same tone; the Reverb Time control against Yamaha's table; and the twenty reverb names compared pair by pair.
Rev 17 · 2026-10-07: Charts that only compared output level or gain are removed from every page except the compressors and gates, where level is what the effect does.
Rev 16 · 2026-10-07: Capture set finished and audited (14,635 takes; the takes recorded through a reverb are all replaced). Corrections: Celeste 1's control shown as Delay is its Feedback Level, and Symphonic's shown as Feedback is its Delay Offset; two Symphonic controls that do not exist on the effect are removed. New charts in time and wave shape rather than level: Delay, where every echo lands as each time control is turned; Distortion, the wave that comes out as the drive rises; Lo-Fi, the output wave sample by sample at each Sampling Freq setting; Chorus and Flanger, the delay line followed as it sweeps; Phaser and Wah, where each notch or peak sits in Hz from moment to moment; Reverb, the separate early reflections in the first quarter second after one click; Modulation and Tech, each side turned up and down from moment to moment.
Rev 15 · 2026-10-06: Pitch Change: a click train in, and when each click comes out.
Rev 14 · 2026-10-06: Distortion: output and distortion against input level on a smooth ramp, harmonics against the pitch of the note, high-note harmonics folding back off 44.1 kHz (no oversampling), a bass note modulating a treble note, input-against-output loops, and the amp and cabinet filters' level and phase.
Rev 13 · 2026-10-06: Lo-Fi on a smoothly rising tone: Word Length sets a clipping ceiling and adds no quantisation noise; the five Lo-Fi effects compared on the same ramp.
Rev 12 · 2026-10-06: Lo-Fi: a rising note against everything that comes out with it, at each sampling-rate setting. Pitch Change: the cluster of lines a shifted note returns as, and the splice window read from it (about 35 ms and 28 ms).
Rev 11 · 2026-10-06: The same routing fault is confirmed for the 1,835 re-takes of 2026-09-30/10-01 (the dry-plus-wet timing takes and the full-rate Lo-Fi takes). No published chart used them; they are withdrawn from the counts and are being re-recorded.
Rev 10 · 2026-10-06: Correction: the all-effects comparison (section 17 of the main report), added earlier today, is withdrawn. Its 625 recordings were made with the Motif's System Reverb left in the signal path and are being re-recorded. New: compressor timing inside the distortion chains, wah filter sweeps, reverb decay per octave band.
Rev 9 · 2026-10-06: Follow-up captures analysed: compressor attack and release against step size, MultiBand Comp 2 band by band, Noise Gate opening, hold and closing times, and distortion on level steps (no sag: the clippers act instant by instant). Release times now require the level to stay recovered for 50 ms, which fixes readings fooled by ringing or by a delay's echo. Capture counts include the overnight batches.
Rev 8 · 2026-10-05: Beyond level curves: gain-reduction speed, release shape, phase-space orbits, harmonic matrices, intermodulation maps, parallel coordinates, a behaviour map and loudness in phon and sone on the Dynamic atlas; harmonic-against-drive matrices (Distortion), stereo LFO orbits (Chorus, Flanger, Phaser, Modulation), an echo map (Delay) and a decay-rate matrix (Reverb).
Rev 7 · 2026-10-04: All figures vector and stacked one per row; control tables replaced by interactive charts; every section in four parts (recap, professional, plain, main points); capture counts include Gap Fill; six more Gap Fill probes analysed (dynamics timing, band staircase, gate ramp, two-tone ladder, tone triplet, pink pluck).
Rev 6 · 2026-10-04: Complete 13-category analysis with detail ladders; all notebooks rebuilt with executed cells and interactive charts.
Rev 5 · 2026-10-01: T28/T29 re-take analysis (dry/wet time references, Lo-Fi full-rate captures); Reverb detail ladders.
Rev 4 · 2026-09-30: Reverb analysis from full 9,876 Gap Fill run; two-voice explanations added to main page sections 1–15.
Rev 3 · 2026-09-29: Gap Fill captures: delay and feedback time laws, LFO maps, drive transfer curves, Lo-Fi rate, early reflections; Gate/Reverse Gate relabelled; interactive charts, atlas links, dark theme.
Rev 2 · 2026-09-28: Gate Reverb time origin fixed; Auto Pan phase and Distortion harmonics computed from data.
Rev 1 · 2026-09-27: First complete report: main analysis and 13 atlas notebooks.