Reverb — effect atlas¶
20 effects · 1,653 captures. Twenty room, hall, plate and special-space algorithms. The questions are how long they ring (T30), how the first 200 ms are built (early reflections), and what the damping and filter controls do to the tail's colour. Decay is read from the tone release; the longest Reverb Time setting outlasts the recording for half of them.
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
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
knob_counts = {'Basement': (12, 2), 'Canyon': (12, 2), 'Hall 1': (8, 1), 'Hall 2': (8, 1), 'Large Hall': (8, 1), 'Medium Hall': (8, 1), 'Plate': (8, 1), 'R3 Hall': (9, 1), 'R3 Plate': (8, 1), 'R3 Room': (9, 1), 'Rich Plate': (8, 0), 'Room 1': (8, 1), 'Room 2': (8, 1), 'Room 3': (8, 1), 'Stage 1': (8, 0), 'Stage 2': (8, 0), 'Tunnel': (12, 2), 'Warm Room': (8, 1), 'White Room': (12, 2), 'Woody Room': (8, 1)}
show(cards.family_overview(df, 'Reverb', knob_counts, curves))
Show code
iviz.family_fig(df, curves, 'Reverb').show()
Recap. Why: to compare every algorithm in the family on one chart. How to read it: each line is one algorithm's energy decay; drag the slider to bring one forward, hover for exact values.
Technical explanation. Each line is one algorithm's energy decay after the probe tone stops, at the capture baseline (the same settings for every algorithm in a group, not the Motif's presets); the slope is the decay rate and where it meets the floor is the length of the tail. Lines that sit on top of each other are one engine: Basement = Canyon = Tunnel = White Room; Room 1 = Room 2 = Room 3; Hall 1 = Hall 2; Large Hall = Medium Hall; Stage 1 = Stage 2; Warm Room = Woody Room.
Plain explanation: the steeper the line falls, the shorter the reverb. Algorithms whose lines overlap are the same reverb under different names.
In other words, the main points:
- 20 algorithms on one chart, all at the same capture-baseline settings.
- 6 shared engines: Basement = Canyon = Tunnel = White Room; Room 1 = Room 2 = Room 3; Hall 1 = Hall 2; Large Hall = Medium Hall; Stage 1 = Stage 2; Warm Room = Woody Room.
Inside the tail: reflections, colour, width, smoothness and identity¶
A reverb time is one number. These charts take each reverb apart in time: the separate reflections at the start and how fast they merge, how the tail's colour changes as it dies, how wide it is at each pitch, how smooth it is, what the Reverb Time control really sets, and which of the twenty names are the same reverb.
Show code
import kinetics, kviz, wviz, rviz
show_parts(wviz.reflection_parts() + rviz.parts() + kviz.decay_parts(df, curves) + kviz.reverb_band_parts())
What it shows. One click into each distinct reverb engine at its default settings, and what comes back over the next quarter second. The recording is the reverb alone, so time is counted from the first sound that returns, not from the click.
How to read it. Each bump is a separate reflection: the left side is drawn above the line and the right below it. Widely spaced bumps are heard as distinct slaps, the size of the space; bumps crowding together are the reverb turning into a smooth wash. Where left and right differ, the reflections arrive from different directions. Use the slider to change reverb.
What it found.
- Hall 1: next return 14 ms after the first, 10 separate returns in the first 50 ms; silence between returns until 43 ms, continuous after that; after 200 ms it is still at 41% of its largest.
- Large Hall: next return 11 ms after the first, 6 separate returns in the first 50 ms; silence between returns until 31 ms, continuous after that; after 200 ms it is still at 32% of its largest.
- Plate: next return 7 ms after the first, 16 separate returns in the first 50 ms; no silence between returns at all; after 200 ms it is still at 31% of its largest.
- R3 Hall: next return 17 ms after the first, 4 separate returns in the first 50 ms; silence between returns until 78 ms, continuous after that; after 200 ms it is still at 38% of its largest.
- R3 Plate: next return 6 ms after the first, 3 separate returns in the first 50 ms; silence between returns until 37 ms, continuous after that; after 200 ms it is still at 28% of its largest.
- R3 Room: next return 17 ms after the first, 5 separate returns in the first 50 ms; silence between returns until 70 ms, continuous after that; after 200 ms it is still at 42% of its largest.
- Rich Plate: next return 19 ms after the first, 9 separate returns in the first 50 ms; no silence between returns at all; after 200 ms it is still at 24% of its largest.
- Room 1: next return 7 ms after the first, 13 separate returns in the first 50 ms; silence between returns until 4 ms, continuous after that; after 200 ms it is still at 29% of its largest.
- Stage 1: next return 15 ms after the first, 10 separate returns in the first 50 ms; silence between returns until 48 ms, continuous after that; after 200 ms it is still at 46% of its largest.
- Warm Room: next return 13 ms after the first, 11 separate returns in the first 50 ms; silence between returns until 6 ms, continuous after that; after 200 ms it is still at 37% of its largest.
- White Room: next return 7 ms after the first, 10 separate returns in the first 50 ms; silence between returns until 4 ms, continuous after that; after 200 ms it is still at 23% of its largest.
What it shows. One click into each reverb engine at its default settings. Each 10 ms after the first sound returns is scored by how much of it has something sounding (above a twentieth of the largest return).
How to read it. A line low on the chart means separate slaps with silence between them; a line at 100% means the returns have merged and there are no gaps left. The sooner a line reaches the top and stays there, the sooner the reverb stops sounding like a place with walls and starts sounding like a wash. Cyan lines merge soonest, amber last.
What it found.
- Plate, Rich Plate, Room 1, Warm Room, White Room are continuous within 13 ms: no audible separate reflections.
- Large Hall (43 ms), R3 Plate (43 ms), Hall 1 (53 ms), Stage 1 (63 ms), R3 Room (83 ms), R3 Hall (93 ms) keep separate reflections longest.
- A click is about 2 ms long by the time it is recorded, so returns closer together than that cannot be told apart and 100% here means no gap longer than about 2 ms.
What it shows. Pink noise through each reverb engine at its default settings, cut dead. The map shows what is left in every third-octave band, every 60 ms from the moment the noise stops.
How to read it. Time runs left to right, pitch bottom to top. Bright means that band is still near the level it had with the noise on; dark means it has died away. A bright region that reaches further right at the bottom than at the top is a tail that turns dark as it dies. Hatched cells are within 10 dB of the recording's own noise. Use the slider to change reverb.
What it found.
- Hall 1: 30 dB down after 1.83 s at 125 Hz, 1.53 s at 1 kHz, 0.33 s at 8 kHz.
- Large Hall: 30 dB down after 1.11 s at 125 Hz, 0.99 s at 1 kHz, 0.51 s at 8 kHz.
- Plate: 30 dB down after 1.83 s at 125 Hz, 1.59 s at 1 kHz, 0.09 s at 8 kHz.
- R3 Hall: 30 dB down after 2.01 s at 125 Hz, 1.53 s at 1 kHz, 0.93 s at 8 kHz.
- R3 Plate: 30 dB down after 1.89 s at 125 Hz, 2.37 s at 1 kHz, 1.59 s at 8 kHz.
- R3 Room: 30 dB down after 1.89 s at 125 Hz, 1.83 s at 1 kHz, 1.29 s at 8 kHz.
- Rich Plate: 30 dB down after 1.35 s at 125 Hz, 1.59 s at 1 kHz, 1.53 s at 8 kHz.
- Room 1: 30 dB down after 1.71 s at 125 Hz, 1.47 s at 1 kHz, 0.21 s at 8 kHz.
- Stage 1: 30 dB down after 1.65 s at 125 Hz, 1.59 s at 1 kHz, 0.39 s at 8 kHz.
- Warm Room: 30 dB down after 0.63 s at 125 Hz, 1.05 s at 1 kHz, 0.57 s at 8 kHz.
- White Room: 30 dB down after 1.41 s at 125 Hz, 1.53 s at 1 kHz, 0.21 s at 8 kHz.
What it shows. The same takes, as the spectrum of the tail frozen at eleven moments 150 ms apart (cyan first, amber last).
How to read it. Each line is the tail's tone at one moment; the lines step downward as the tail dies. Lines that stay the same shape and simply sink are a tail whose colour does not change. Lines that pivot, falling faster on the right, are a tail losing its treble first. A line stops where its band has sunk into the recording's noise.
What it found.
- The bass outlasts the treble most in Plate (20 times as long at 125 Hz as at 8 kHz) and least in Rich Plate (0.9 times).
What it shows. Pink noise, the same in both speakers, into each reverb engine; the reverb's left and right outputs compared in each octave band, over the last second and a half of the noise and the tail after it.
How to read it. +1 means the two sides carry the same sound in that band (it sits in the middle, like mono); 0 means they are unrelated (as wide as it can be); below 0 means they tend to move in opposite directions. Bright cells are narrow, dark cells wide.
What it found.
- Nearly the same on both sides in the bass (above +0.5 at 125 Hz): Hall 1, Plate, R3 Hall, R3 Plate, R3 Room, Room 1, Stage 1, White Room.
- Unrelated at every pitch, the bass included: Large Hall, Rich Plate, Warm Room.
- From 1 kHz up every engine is close to unrelated (average −0.03).
- Leaning opposite: Plate at 1,000 Hz (−0.43), R3 Plate at 1,000 Hz (−0.54).
- The lowest band holds few independent stretches of sound in this time, so its figure is good to about ±0.1.
What it shows. The same comparison over the whole range of pitch, in windows a tenth of a second long, from half a second before the noise stops to a second and a half after.
How to read it. A line that falls after 0 would be a reverb that gets wider as it rings out; a level line is one whose width does not change. Each line is the average of three takes at different loudness.
What it found.
- No engine changes: between the first and the second half-second of the tail the largest shift is 0.10, inside the wobble of the lines themselves.
- The width is built into each engine and is the same while the sound plays and after it stops.
- The three takes agree to within 0.04, so it does not depend on loudness either.
- The overall figure sits well above 0 for the engines with a narrow bass because pink noise has most of its energy there.
What it shows. Two thousand instants from the first half second of each tail: where the left side was (across) against where the right side was at the same instant (up).
How to read it. A cloud stretched along the rising dotted line means the two sides mostly move together (narrow); a round cloud means they are unrelated (wide); a cloud along the falling line would mean one side is the other turned upside down, a trick for faking width that collapses in mono. Use the slider to change reverb.
What it found.
- No engine draws a cloud along the falling line: none relies on turning one side upside down.
- Large Hall, Rich Plate, Warm Room draw round clouds; Hall 1, Plate, R3 Hall, R3 Plate, R3 Room, Room 1, Stage 1, White Room draw clouds leaning along the rising line, which is their shared bass.
What it shows. One click into each engine; the part of the tail from 0.12 to 0.72 s after the first return. Its level is followed 5 ms at a time and the wobble about its smooth fall is measured, then compared with the wobble of random noise that has the same tone and the same fall (thirty versions, made from the tail itself).
How to read it. A bar at the dotted line is a tail as smooth as it is possible to be: it wobbles no more than chance. A taller bar is a tail with lumps in it, heard as graininess or flutter on short sounds. The thin marks show how far the noise yardstick itself varies.
What it found.
- As smooth as noise: Plate, R3 Plate, Room 1.
- Roughest: White Room (1.69 times) and Rich Plate (1.69 times).
- In order: Plate 1.02, R3 Plate 1.13, Room 1 1.14, Stage 1 1.26, R3 Room 1.27, Hall 1 1.29, R3 Hall 1.30, Warm Room 1.38, Large Hall 1.47, Rich Plate 1.69, White Room 1.69.
What it shows. Noise cut dead through two engines at seven Reverb Time settings, with the time each octave band takes to fall 60 dB set against the time Yamaha's data list gives for that setting.
How to read it. Points on the dotted line decay exactly as documented. Above the line the tail lasts longer than the label says, below it shorter. The four lines are four pitches (cyan lowest); where they fan apart, the label describes one pitch range and not the others. Use the slider to change reverb.
What it found.
- Hall 1: at 250 Hz the tail lasts 99% of the documented time, at 2 kHz 88% (medians over the settings from 1.2 s up); the shortest setting, documented as 0.3 s, measures 0.47 s at 500 Hz.
- R3 Hall: at 250 Hz the tail lasts 111% of the documented time, at 2 kHz 98% (medians over the settings from 1.2 s up); the shortest setting, documented as 0.3 s, measures 0.33 s at 500 Hz.
What it shows. The first 170 ms of every reverb algorithm's response to the same test signal, each compared with every other. Algorithms that share a set of controls were captured with every control at the same value.
How to read it. Each cell is one pair: 1.00 means the two names produced the same response, so they are one piece of processing under two names; a figure near 0 means they have nothing in common. Matching names are placed next to each other, so each block of bright cells along the diagonal is one reverb.
What it found.
- The 20 names give 12 different responses.
- The same at the same settings: Basement = Tunnel = White Room; Hall 1 = Hall 2; Large Hall = Medium Hall; Room 1 = Room 2 = Room 3; Stage 1 = Stage 2; Warm Room = Woody Room.
- On their own: Canyon, Plate, R3 Hall, R3 Plate, R3 Room, Rich Plate.
- Close but not the same: Canyon and Basement (0.93), Tunnel and Canyon (0.93), White Room and Canyon (0.93); a pair like that is the same design with something small changed.
- There is nothing in between: apart from those, no pair scores between 0.2 and 0.9 (the largest unrelated score is 0.13).
- Names in one block still differ as presets, because their factory default values differ.
What it shows. How fast each reverb dies away, measured separately over each 10 dB of its fall after a tone stops, at default settings. Every cell is expressed as the time a full 60 dB decay would take at that rate, so a reverb that decays at one steady rate has the same number all the way across.
How to read it. One row per reverb, longest at the top; left to right follows the decay from its start down to −40 dB. Brighter amber is a slower decay. A row that brightens to the right has a tail that hangs on longer than its start suggests; a row that darkens falls away faster as it fades.
What it found.
- Steady, single-rate decays (all four stretches within 15% of each other): R3 Plate, R3 Room, Rich Plate, Plate, Canyon, White Room, Hall 2, Hall 1, Basement, Tunnel.
- Tails that slow down: Warm Room (2.8 s at the start, 4.0 s later); Woody Room (2.8 s at the start, 4.0 s later).
- The rest wander by more than 15% without a clear trend.
- A single reverb-time figure describes the first group well and hides what the others do.
- Below −40 dB the recording's noise floor takes over, so the matrix stops there; the last column is the one most affected by the noise correction.
What it shows. Two seconds of pink noise cut dead, through each of the eleven distinct reverb engines at default settings. Each cell is how long that octave band takes to die away (scaled to a 60 dB fall, fitted from 5 to 25 dB down).
How to read it. One row per reverb, longest at the top; bass on the left, treble on the right. Brighter amber is a longer decay. A row that darkens to the right is a reverb whose treble dies first, as in a real room; an even row keeps its treble ringing as long as its bass.
What it found.
- Treble lasts longest in Rich Plate (3.7 s at 8 kHz against 4.1 s at 500 Hz); R3 Plate (4.5 s at 8 kHz against 5.6 s at 500 Hz); R3 Room (3.1 s at 8 kHz against 4.1 s at 500 Hz).
- It dies fastest in Plate (1.1 s against 4.0 s); Room 1 (1.4 s against 4.1 s); White Room (1.5 s against 4.0 s).
- Played 12 and 24 dB quieter, every band that can be read at all three levels decays in the same time to within 1.2%: the reverbs are linear, with no level-dependent behaviour in the tail.
- This reading comes from a different probe (cut-off noise, not the tone release used in the matrix above) and reaches the 8 kHz band, which the tone could not.
Basement¶
Show code
show_card('Basement')
Basement: what the measurements say¶
Recap. A reverb with 14 tested controls, 12 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 3.89 s. 2 do nothing with the others at default. Measured with 83 captures: 83 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -20.7 dBFS RMS (crest 18.0 dB); stereo width 0.55, L/R correlation +0.40; spectral tilt -0.32 dB/octave; 10% of the impulse response's energy in its first 5 ms; decay T30 3.89 s, EDT 3.70 s.
Structure:
- Reverb Time → T30: 0 → 0.16 s, 17 → 1.81 s, 34 → 3.49 s, 51 → 5.74 s, 69 → 9.99 s
Plain explanation: The control to reach for first is ER Reverb Balance: decay time 0.08 → 3.89 s. After that, Reverb Time, Diffusion and HPF Cutoff make the next biggest differences. Initial Delay and Reverb Delay made no measurable difference with the other controls at default. At default the tail takes about 3.9 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 12 of 14 tested controls measurably change the sound; 2 do nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 21.4× the smallest change that matters (decay time 0.08 → 3.89 s).
- At default: stereo width 0.55, decay T30 3.89 s, output -20.7 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Basement')
Canyon¶
Show code
show_card('Canyon')
Canyon: what the measurements say¶
Recap. A reverb with 14 tested controls, 12 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: raises everything below ~266 Hz by up to 39 dB. 2 do nothing with the others at default. Measured with 107 captures: 83 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -16.2 dBFS RMS (crest 12.7 dB); stereo width 0.41, L/R correlation +0.66; spectral tilt -1.11 dB/octave; 10% of the impulse response's energy in its first 5 ms; decay T30 4.00 s, EDT 3.94 s.
Structure:
- Reverb Time → T30: 0 → 0.17 s, 17 → 1.85 s, 34 → 3.60 s, 51 → 5.90 s, 69 → 7.72 s
Two-control pairs captured: ER Reverb Balance×Diffusion, ER Reverb Balance×HPF Cutoff, ER Reverb Balance×Reverb Time, HPF Cutoff×Diffusion, Reverb Time×Diffusion, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is ER Reverb Balance: raises everything below ~266 Hz by up to 39 dB. After that, Reverb Time, HPF Cutoff and Diffusion make the next biggest differences. Initial Delay and Reverb Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default it has a moderate stereo spread.
In other words, the main points:
- 12 of 14 tested controls measurably change the sound; 2 do nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 24.9× the smallest change that matters (raises everything below ~266 Hz by up to 39 dB).
- At default: stereo width 0.41, decay T30 4.00 s, output -16.2 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Canyon')
Hall 1¶
Show code
show_card('Hall 1')
Hall 1: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.44 → 6.51 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -24.3 dBFS RMS (crest 20.8 dB); stereo width 0.61, L/R correlation +0.25; spectral tilt +0.23 dB/octave; 6% of the impulse response's energy in its first 5 ms; decay T30 3.96 s, EDT 4.03 s.
Structure:
- Reverb Time → T30: 0 → 0.44 s, 17 → 1.97 s, 34 → 3.68 s, 51 → 6.51 s, 69 → 2.41 s (lower bound)
Two-control pairs captured: Diffusion×Feedback, Diffusion×HPF Cutoff, HPF Cutoff×Feedback, Reverb Time×Diffusion, Reverb Time×Feedback, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Caveats:
- 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 Reverb Time: decay time 0.44 → 6.51 s. After that, Diffusion, HPF Cutoff and Feedback make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: Reverb Time, 14.8× the smallest change that matters (decay time 0.44 → 6.51 s).
- At default: stereo width 0.61, decay T30 3.96 s, output -24.3 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Hall 1')
Hall 2¶
Show code
show_card('Hall 2')
Hall 2: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.44 → 6.53 s. 1 does nothing with the others at default. Measured with 63 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -23.7 dBFS RMS (crest 20.2 dB); stereo width 0.60, L/R correlation +0.29; spectral tilt +0.03 dB/octave; 6% of the impulse response's energy in its first 5 ms; decay T30 3.97 s, EDT 4.04 s.
Structure:
- Reverb Time → T30: 0 → 0.44 s, 17 → 1.97 s, 34 → 3.67 s, 51 → 6.53 s, 69 → 1.67 s
Plain explanation: The control to reach for first is Reverb Time: decay time 0.44 → 6.53 s. After that, Diffusion, HPF Cutoff and Feedback make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: Reverb Time, 14.8× the smallest change that matters (decay time 0.44 → 6.53 s).
- At default: stereo width 0.60, decay T30 3.97 s, output -23.7 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Hall 2')
Large Hall¶
Show code
show_card('Large Hall')
Large Hall: what the measurements say¶
Recap. A reverb with 9 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is HPF Cutoff: lowers everything below ~648 Hz by up to 45 dB. 1 does nothing with the others at default. Measured with 92 captures: 68 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -30.6 dBFS RMS (crest 25.6 dB); stereo width 0.72, L/R correlation -0.04; spectral tilt -0.25 dB/octave; 5% of the impulse response's energy in its first 5 ms; decay T30 2.57 s, EDT 2.30 s.
Structure:
- Reverb Time → T30: 0 → 0.27 s, 17 → 1.20 s, 34 → 2.13 s, 51 → 3.09 s, 69 → 6.01 s
Two-control pairs captured: HPF Cutoff×High Ratio, HPF Cutoff×Low Ratio, HPF Cutoff×Reverb Time, Low Ratio×High Ratio, Reverb Time×High Ratio, Reverb Time×Low Ratio (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is HPF Cutoff: lowers everything below ~648 Hz by up to 45 dB. After that, Reverb Time, Low Ratio and High Ratio make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 2.6 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 9 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: HPF Cutoff, 13.9× the smallest change that matters (lowers everything below ~648 Hz by up to 45 dB).
- At default: stereo width 0.72, decay T30 2.57 s, output -30.6 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Large Hall')
Medium Hall¶
Show code
show_card('Medium Hall')
Medium Hall: what the measurements say¶
Recap. A reverb with 9 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is HPF Cutoff: lowers everything below ~648 Hz by up to 45 dB. 1 does nothing with the others at default. Measured with 68 captures: 68 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -30.7 dBFS RMS (crest 25.7 dB); stereo width 0.72, L/R correlation -0.04; spectral tilt -0.25 dB/octave; 5% of the impulse response's energy in its first 5 ms; decay T30 2.57 s, EDT 2.30 s.
Structure:
- Reverb Time → T30: 0 → 0.27 s, 17 → 1.20 s, 34 → 2.13 s, 51 → 3.09 s, 69 → 6.01 s
Plain explanation: The control to reach for first is HPF Cutoff: lowers everything below ~648 Hz by up to 45 dB. After that, Room Size, Reverb Time and Low Ratio make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 2.6 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 9 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: HPF Cutoff, 13.9× the smallest change that matters (lowers everything below ~648 Hz by up to 45 dB).
- At default: stereo width 0.72, decay T30 2.57 s, output -30.7 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Medium Hall')
Plate¶
Show code
show_card('Plate')
Plate: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.14 → 4.05 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -23.9 dBFS RMS (crest 20.0 dB); stereo width 0.57, L/R correlation +0.35; spectral tilt -0.19 dB/octave; 7% of the impulse response's energy in its first 5 ms; decay T30 4.05 s, EDT 4.10 s.
Structure:
- Reverb Time → T30: 0 → 0.30 s, 17 → 1.99 s, 34 → 3.75 s, 51 → 6.85 s, 69 → 0.70 s (lower bound)
Two-control pairs captured: ER Reverb Balance×Diffusion, ER Reverb Balance×HPF Cutoff, ER Reverb Balance×Reverb Time, HPF Cutoff×Diffusion, Reverb Time×Diffusion, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Caveats:
- 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 ER Reverb Balance: decay time 0.14 → 4.05 s. After that, Reverb Time, HPF Cutoff and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.1 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 18.4× the smallest change that matters (decay time 0.14 → 4.05 s).
- At default: stereo width 0.57, decay T30 4.05 s, output -23.9 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Plate')
R3 Hall¶
Show code
show_card('R3 Hall')
R3 Hall: what the measurements say¶
Recap. A reverb with 10 tested controls, 9 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.11 → 4.33 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -23.5 dBFS RMS (crest 19.9 dB); stereo width 0.62, L/R correlation +0.23; spectral tilt +0.31 dB/octave; 4% of the impulse response's energy in its first 5 ms; decay T30 4.33 s, EDT 4.18 s.
Structure:
- Reverb Time → T30: 0 → 0.42 s, 17 → 2.20 s, 34 → 4.07 s, 51 → 7.75 s, 69 → 0.80 s (lower bound)
Two-control pairs captured: ER Reverb Balance×Diffusion, ER Reverb Balance×Feedback, ER Reverb Balance×Reverb Time, Feedback×Diffusion, Reverb Time×Diffusion, Reverb Time×Feedback (interaction analysis in the main notebook).
Caveats:
- 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 ER Reverb Balance: decay time 0.11 → 4.33 s. After that, Reverb Time, Feedback and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.3 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 9 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 20.3× the smallest change that matters (decay time 0.11 → 4.33 s).
- At default: stereo width 0.62, decay T30 4.33 s, output -23.5 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('R3 Hall')
R3 Plate¶
Show code
show_card('R3 Plate')
R3 Plate: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.43 → 9.82 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -24.0 dBFS RMS (crest 20.7 dB); stereo width 0.66, L/R correlation +0.13; spectral tilt +0.09 dB/octave; 8% of the impulse response's energy in its first 5 ms; decay T30 6.11 s, EDT 5.81 s.
Structure:
- Reverb Time → T30: 0 → 0.43 s, 17 → 2.91 s, 34 → 5.63 s, 51 → 9.82 s, 69 → 3.46 s
Two-control pairs captured: ER Reverb Balance×Diffusion, Reverb Delay×Diffusion, Reverb Delay×ER Reverb Balance, Reverb Time×Diffusion, Reverb Time×ER Reverb Balance, Reverb Time×Reverb Delay (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is Reverb Time: decay time 0.43 → 9.82 s. After that, Reverb Delay, ER Reverb Balance and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 6.1 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: Reverb Time, 17.2× the smallest change that matters (decay time 0.43 → 9.82 s).
- At default: stereo width 0.66, decay T30 6.11 s, output -24.0 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('R3 Plate')
R3 Room¶
Show code
show_card('R3 Room')
R3 Room: what the measurements say¶
Recap. A reverb with 10 tested controls, 9 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.06 → 4.24 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -24.0 dBFS RMS (crest 20.5 dB); stereo width 0.69, L/R correlation +0.04; spectral tilt +0.28 dB/octave; 3% of the impulse response's energy in its first 5 ms; decay T30 4.23 s, EDT 3.70 s.
Structure:
- Reverb Time → T30: 0 → 0.30 s, 17 → 2.20 s, 34 → 3.97 s, 51 → 6.92 s, 69 → 0.46 s (lower bound)
Two-control pairs captured: ER Reverb Balance×Diffusion, ER Reverb Balance×Feedback, ER Reverb Balance×Reverb Time, Feedback×Diffusion, Reverb Time×Diffusion, Reverb Time×Feedback (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is ER Reverb Balance: decay time 0.06 → 4.24 s. After that, Reverb Time, Feedback and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.2 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 9 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 23.2× the smallest change that matters (decay time 0.06 → 4.24 s).
- At default: stereo width 0.69, decay T30 4.23 s, output -24.0 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('R3 Room')
Rich Plate¶
Show code
show_card('Rich Plate')
Rich Plate: what the measurements say¶
Recap. A reverb with 9 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.85 → 7.25 s. Measured with 92 captures: 68 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -26.7 dBFS RMS (crest 23.0 dB); stereo width 0.71, L/R correlation -0.02; spectral tilt +1.22 dB/octave; 4% of the impulse response's energy in its first 5 ms; decay T30 4.16 s, EDT 4.56 s.
Structure:
- Reverb Time → T30: 0 → 0.85 s, 17 → 2.46 s, 34 → 3.77 s, 51 → 7.25 s, 69 → 1.27 s (lower bound)
Two-control pairs captured: HPF Cutoff×Initial Delay, Reverb Time×HPF Cutoff, Reverb Time×Initial Delay, Reverb Time×Room Size, Room Size×HPF Cutoff, Room Size×Initial Delay (interaction analysis in the main notebook).
Caveats:
- 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 Reverb Time: decay time 0.85 → 7.25 s. After that, Room Size, HPF Cutoff and Initial Delay make the next biggest differences. At default the tail takes about 4.2 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 9 tested controls measurably change the sound.
- Biggest lever beyond mix and level: Reverb Time, 11.8× the smallest change that matters (decay time 0.85 → 7.25 s).
- At default: stereo width 0.71, decay T30 4.16 s, output -26.7 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Rich Plate')
Room 1¶
Show code
show_card('Room 1')
Room 1: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 4.45 s. 1 does nothing with the others at default. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -23.7 dBFS RMS (crest 20.1 dB); stereo width 0.58, L/R correlation +0.33; spectral tilt -0.47 dB/octave; 8% of the impulse response's energy in its first 5 ms; decay T30 4.46 s, EDT 3.43 s.
Structure:
- Reverb Time → T30: 0 → 0.32 s, 17 → 1.86 s, 34 → 4.10 s, 51 → 7.08 s, 69 → 2.57 s (lower bound)
Two-control pairs captured: ER Reverb Balance×Diffusion, ER Reverb Balance×HPF Cutoff, ER Reverb Balance×Reverb Time, HPF Cutoff×Diffusion, Reverb Time×Diffusion, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Caveats:
- 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 ER Reverb Balance: decay time 0.08 → 4.45 s. After that, Reverb Time, HPF Cutoff and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.5 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 22.2× the smallest change that matters (decay time 0.08 → 4.45 s).
- At default: stereo width 0.58, decay T30 4.46 s, output -23.7 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Room 1')
Room 2¶
Show code
show_card('Room 2')
Room 2: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 4.46 s. 1 does nothing with the others at default. Measured with 63 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -23.7 dBFS RMS (crest 19.8 dB); stereo width 0.57, L/R correlation +0.35; spectral tilt -0.52 dB/octave; 8% of the impulse response's energy in its first 5 ms; decay T30 4.47 s, EDT 3.40 s.
Structure:
- Reverb Time → T30: 0 → 0.32 s, 17 → 1.87 s, 34 → 4.12 s, 51 → 7.08 s, 69 → 2.55 s (lower bound)
Caveats:
- 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 ER Reverb Balance: decay time 0.08 → 4.46 s. After that, Reverb Time, HPF Cutoff and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.5 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 22.2× the smallest change that matters (decay time 0.08 → 4.46 s).
- At default: stereo width 0.57, decay T30 4.47 s, output -23.7 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Room 2')
Room 3¶
Show code
show_card('Room 3')
Room 3: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 4.44 s. 1 does nothing with the others at default. Measured with 63 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -24.3 dBFS RMS (crest 20.4 dB); stereo width 0.60, L/R correlation +0.28; spectral tilt -0.28 dB/octave; 8% of the impulse response's energy in its first 5 ms; decay T30 4.44 s, EDT 3.41 s.
Structure:
- Reverb Time → T30: 0 → 0.32 s, 17 → 1.87 s, 34 → 4.10 s, 51 → 7.07 s, 69 → 1.33 s (lower bound)
Caveats:
- 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 ER Reverb Balance: decay time 0.08 → 4.44 s. After that, Reverb Time, HPF Cutoff and Diffusion make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.4 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 22.2× the smallest change that matters (decay time 0.08 → 4.44 s).
- At default: stereo width 0.60, decay T30 4.44 s, output -24.3 dBFS RMS.
- Main caveat: some long settings decay more slowly than the recording allows; their T30 is a lower bound.
- Still to measure: T1, T4, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Room 3')
Stage 1¶
Show code
show_card('Stage 1')
Stage 1: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.49 → 6.82 s. Measured with 87 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -22.9 dBFS RMS (crest 19.4 dB); stereo width 0.58, L/R correlation +0.32; spectral tilt -0.02 dB/octave; 5% of the impulse response's energy in its first 5 ms; decay T30 4.11 s, EDT 3.90 s.
Structure:
- Reverb Time → T30: 0 → 0.49 s, 17 → 1.96 s, 34 → 3.78 s, 51 → 6.82 s, 69 → nan s (lower bound)
Two-control pairs captured: Diffusion×ER Reverb Balance, Diffusion×HPF Cutoff, ER Reverb Balance×HPF Cutoff, Reverb Time×Diffusion, Reverb Time×ER Reverb Balance, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is Reverb Time: decay time 0.49 → 6.82 s. After that, Diffusion, ER Reverb Balance and HPF Cutoff make the next biggest differences. At default the tail takes about 4.1 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound.
- Biggest lever beyond mix and level: Reverb Time, 14.4× the smallest change that matters (decay time 0.49 → 6.82 s).
- At default: stereo width 0.58, decay T30 4.11 s, output -22.9 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Stage 1')
Stage 2¶
Show code
show_card('Stage 2')
Stage 2: what the measurements say¶
Recap. A reverb with 10 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.50 → 6.82 s. Measured with 63 captures: 63 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -24.3 dBFS RMS (crest 20.4 dB); stereo width 0.60, L/R correlation +0.27; spectral tilt +0.26 dB/octave; 5% of the impulse response's energy in its first 5 ms; decay T30 4.10 s, EDT 3.90 s.
Structure:
- Reverb Time → T30: 0 → 0.50 s, 17 → 1.96 s, 34 → 3.78 s, 51 → 6.82 s, 69 → nan s (lower bound)
Plain explanation: The control to reach for first is Reverb Time: decay time 0.50 → 6.82 s. After that, Diffusion, ER Reverb Balance and HPF Cutoff make the next biggest differences. At default the tail takes about 4.1 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 10 tested controls measurably change the sound.
- Biggest lever beyond mix and level: Reverb Time, 14.3× the smallest change that matters (decay time 0.50 → 6.82 s).
- At default: stereo width 0.60, decay T30 4.10 s, output -24.3 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Stage 2')
Tunnel¶
Show code
show_card('Tunnel')
Tunnel: what the measurements say¶
Recap. A reverb with 14 tested controls, 12 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 3.63 s. 2 do nothing with the others at default. Measured with 83 captures: 83 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -20.6 dBFS RMS (crest 17.2 dB); stereo width 0.55, L/R correlation +0.40; spectral tilt -0.33 dB/octave; 10% of the impulse response's energy in its first 5 ms; decay T30 3.63 s, EDT 3.64 s.
Structure:
- Reverb Time → T30: 0 → 0.16 s, 17 → 1.62 s, 34 → 3.35 s, 51 → 5.21 s, 69 → 10.41 s
Plain explanation: The control to reach for first is ER Reverb Balance: decay time 0.08 → 3.63 s. After that, Reverb Time, Diffusion and HPF Cutoff make the next biggest differences. Initial Delay and Reverb Delay made no measurable difference with the other controls at default. At default the tail takes about 3.6 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 12 of 14 tested controls measurably change the sound; 2 do nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 21.3× the smallest change that matters (decay time 0.08 → 3.63 s).
- At default: stereo width 0.55, decay T30 3.63 s, output -20.6 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Tunnel')
Warm Room¶
Show code
show_card('Warm Room')
Warm Room: what the measurements say¶
Recap. A reverb with 9 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.45 → 7.16 s. 1 does nothing with the others at default. Measured with 92 captures: 68 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -29.7 dBFS RMS (crest 24.4 dB); stereo width 0.74, L/R correlation -0.11; spectral tilt -0.20 dB/octave; 3% of the impulse response's energy in its first 5 ms; decay T30 4.04 s, EDT 2.87 s.
Structure:
- Reverb Time → T30: 0 → 0.45 s, 17 → 1.72 s, 34 → 3.55 s, 51 → 4.74 s, 69 → 7.16 s
Two-control pairs captured: HPF Cutoff×High Ratio, HPF Cutoff×Low Ratio, Low Ratio×High Ratio, Reverb Time×HPF Cutoff, Reverb Time×High Ratio, Reverb Time×Low Ratio (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is Reverb Time: decay time 0.45 → 7.16 s. After that, HPF Cutoff, Low Ratio and High Ratio make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 9 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: Reverb Time, 15.1× the smallest change that matters (decay time 0.45 → 7.16 s).
- At default: stereo width 0.74, decay T30 4.04 s, output -29.7 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Warm Room')
White Room¶
Show code
show_card('White Room')
White Room: what the measurements say¶
Recap. A reverb with 14 tested controls, 12 of which measurably change the sound. Beyond mix and level, the biggest lever is ER Reverb Balance: decay time 0.08 → 3.97 s. 2 do nothing with the others at default. Measured with 107 captures: 83 on the main sweep + tone probe (one control at a time), 0 on matched probes, 24 two-control pairs.
Technical explanation. At default settings: output -20.5 dBFS RMS (crest 17.5 dB); stereo width 0.55, L/R correlation +0.40; spectral tilt -0.33 dB/octave; 10% of the impulse response's energy in its first 5 ms; decay T30 3.97 s, EDT 3.90 s.
Structure:
- Reverb Time → T30: 0 → 0.16 s, 17 → 1.83 s, 34 → 3.59 s, 51 → 5.84 s, 69 → 10.44 s
Two-control pairs captured: Diffusion×HPF Cutoff, ER Reverb Balance×Diffusion, ER Reverb Balance×HPF Cutoff, ER Reverb Balance×Reverb Time, Reverb Time×Diffusion, Reverb Time×HPF Cutoff (interaction analysis in the main notebook).
Plain explanation: The control to reach for first is ER Reverb Balance: decay time 0.08 → 3.97 s. After that, Reverb Time, Diffusion and HPF Cutoff make the next biggest differences. Initial Delay and Reverb Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 12 of 14 tested controls measurably change the sound; 2 do nothing with the others at default.
- Biggest lever beyond mix and level: ER Reverb Balance, 21.7× the smallest change that matters (decay time 0.08 → 3.97 s).
- At default: stereo width 0.55, decay T30 3.97 s, output -20.5 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('White Room')
Woody Room¶
Show code
show_card('Woody Room')
Woody Room: what the measurements say¶
Recap. A reverb with 9 tested controls, 8 of which measurably change the sound. Beyond mix and level, the biggest lever is Reverb Time: decay time 0.45 → 7.15 s. 1 does nothing with the others at default. Measured with 68 captures: 68 on the main sweep + tone probe (one control at a time), 0 on matched probes, 0 two-control pairs.
Technical explanation. At default settings: output -29.7 dBFS RMS (crest 24.4 dB); stereo width 0.74, L/R correlation -0.11; spectral tilt -0.20 dB/octave; 3% of the impulse response's energy in its first 5 ms; decay T30 4.04 s, EDT 2.87 s.
Structure:
- Reverb Time → T30: 0 → 0.45 s, 17 → 1.71 s, 34 → 3.55 s, 51 → 4.74 s, 69 → 7.15 s
Plain explanation: The control to reach for first is Reverb Time: decay time 0.45 → 7.15 s. After that, HPF Cutoff, Low Ratio and High Ratio make the next biggest differences. Initial Delay made no measurable difference with the other controls at default. At default the tail takes about 4.0 s to die away. At default left and right are largely independent, so it sounds wide.
In other words, the main points:
- 8 of 9 tested controls measurably change the sound; 1 does nothing with the others at default.
- Biggest lever beyond mix and level: Reverb Time, 15.1× the smallest change that matters (decay time 0.45 → 7.15 s).
- At default: stereo width 0.74, decay T30 4.04 s, output -29.7 dBFS RMS.
- Still to measure: T1, T5 (see
TESTS_NEEDED.md).
Show code
show_knobs('Woody Room')
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.