Introduction
NIVIEM Phase One is a detailed digital emulation inspired by the legendary Maestro PS-1A Phase Shifter (1971), designed by Tom Oberheim and manufactured by Gibson/Maestro. The PS-1A was one of the first commercially available phaser pedals and became a defining sound of 1970s music.
What Makes This Plugin Special
- Authentic to the Core: Vintage Mode uses the exact same DSP code as the original PS-1A — no shortcuts, no compromises
- True 6-Stage All-Pass Cascade: creates 3 sweeping notches for rich, complex phasing
- Three Preset Speeds: Slow (0.5 Hz), Medium (1.0 Hz), Fast (6.0 Hz) — matching the original
- Continuous Rate Knob: dial in any LFO rate from 0.05 Hz to 12 Hz in Modern Free
- Tempo Sync — 15 Divisions: lock to host tempo from 1/32 through 4/1, including triplets and dotted figures
- Stereo Spread: independent L/R LFO phase offset; mono-compatible at zero, 180° at maximum
- Output Gain Trim: ±12 dB clean gain stage after the phaser
- Leslie-Style Speed Ramping: smooth acceleration and deceleration when switching speeds
- 30 Factory Presets: across 7 categories — plus user save / delete / rename
- A/B Compare: two full parameter snapshots in the header, copy in either direction
- Nivipedia: in-plugin encyclopedia covering every control, mode, DSP concept and historical context
- Right-click on any control: Reset to Default + What is this? (jumps to the matching Nivipedia entry)
- Hover tooltips: name, current value and range — live update during drag
- Double-click for direct value entry: premium centred dialog with cream-LCD field and amber clamp flash
- Vintage Mode: locks to 100 % authentic PS-1A behaviour with no modern additions
- Modern Mode: every modern convenience without ever crossing back into the Vintage signal path
- Zero-Latency Processing: real-time performance with no perceptible delay
- Premium DSP Quality: 64-bit coefficient calculations, DC blocking, denormal prevention
- Premium Cream-Chassis UI: period-accurate Lowrey-style speed rockers, FSH-1-style illuminated power, animated phase-shift visualiser
The Original: Maestro PS-1A (1971)
Historical Context
The Maestro PS-1 Phase Shifter was born from Tom Oberheim's desire to electronically simulate the sound of a Leslie rotating speaker cabinet. While the Leslie creates its distinctive sound through physical rotation of horn and drum assemblies, Oberheim realized he could approximate this effect using phase-shifting circuits.
The PS-1 debuted in 1971, with the refined PS-1A appearing in early 1972. It quickly became a studio staple and can be heard on countless classic recordings.
Design Philosophy
Tom Oberheim chose a 6-stage all-pass filter topology because it creates 3 notches in the frequency spectrum - enough for a rich, complex phasing effect without becoming muddy or metallic. The three preset speeds were carefully chosen to provide musically useful rates:
- Slow: A gentle, breathing 2-second sweep
- Medium: The classic 1-second phaser pulse
- Fast: A vibrato-like warble effect
The Leslie-style speed ramping was a stroke of genius - instead of jarring instant speed changes, the LFO smoothly accelerates or decelerates, just like a real rotating speaker taking time to speed up or slow down.
Notable Users
The PS-1A's distinctive sound was embraced by many legendary artists:
- John Paul Jones (Led Zeppelin) - The ethereal keyboards on "No Quarter"
- George Harrison (The Beatles) - "This Guitar (Can't Keep From Crying)"
- Ernie Isley (Isley Brothers) - The iconic phased guitar on "That Lady" (1973)
- Steve Howe (Yes) - Progressive rock guitar textures
- Alex Lifeson (Rush) - Phased rhythm guitar tones
- Waylon Jennings - Outlaw country phaser tones
- Martin Gore (Depeche Mode) - Synth textures
Original Hardware Specifications
| Component | Value |
|---|---|
| Power Supply | ±15V dual rail |
| Op-Amps | 1458 dual (4 ICs = 8 sections) |
| JFETs | 2N4302 or 2N4303 (matched set of 6) |
| JFET Rds(on) | ~100-500 ohms |
| JFET Rds(off) | >2M ohms |
| Speed Buttons | Lowrey organ style rockers |
| Button Colors | Blue/Yellow/Red (some units: Green/Yellow/Red) |
| Input/Output | Mono |
| Designer | Tom Oberheim |
Authenticity & Circuit-Level Emulation
Our Approach to Emulation
The NIVIEM Phase One was developed using rigorous methodology:
- Primary Source Analysis: R.G. Keen's traced schematic and technical documentation
- Reference Verification: Cross-referenced with Patchstorage PS-1A emulation values
- Component Verification: Period-correct JFET characteristics, op-amp topology
- Circuit Topology Preservation: Signal flow matches the original exactly
- Behavioral Accuracy: Each circuit block analyzed and implemented accordingly
Critical Implementation Details
6-Stage All-Pass Filter Cascade
The original PS-1A uses 6 cascaded first-order all-pass filters:
| Parameter | Value |
|---|---|
| Filter Stages | 6 (creates 3 notches) |
| Transfer Function | H(z) = (a₁ + z⁻¹) / (1 + a₁·z⁻¹) |
| Coefficient Formula | a₁ = (tan(π·fb/fs) - 1) / (tan(π·fb/fs) + 1) |
| Break Freq Range | 20 Hz - 5000 Hz (logarithmic sweep) |
Why 6 Stages?
- Total DC phase shift: 6 × 180° = 1080° = 3 × 360°
- Number of notches: 6 ÷ 2 = 3 notches
- Rich, complex interference patterns
- Not too many stages (which can sound metallic)
Triangle Wave LFO
The PS-1A uses a triangle wave LFO rather than a sine wave:
| Characteristic | Reason |
|---|---|
| Linear Sweep | Notches move at constant speed |
| Symmetric | Equal time ascending and descending |
| No Discontinuities | Smooth transitions at peaks and troughs |
Triangle Wave Formula:
y(t) = 4·|phase - 0.5| - 1
Leslie-Style Speed Ramping
When switching speeds, the LFO doesn't instantly jump to the new rate:
| Parameter | Value |
|---|---|
| Ramp Time Constant | 0.5 seconds (τ) |
| Behavior | Exponential smoothing |
| Full Transition | ~1.5 seconds to reach 95% |
This creates the same expressive quality as a Leslie speaker's horn speeding up or slowing down.
Installation
System Requirements
| Platform | Requirements |
|---|---|
| macOS | 11.0 (Big Sur) or later, Intel or Apple Silicon |
| Windows | Windows 10/11 (64-bit), WebView2 Runtime |
- Formats: Audio Unit (AU - macOS only), VST3 (macOS & Windows)
- DAW: Logic Pro, GarageBand, Ableton Live, Cubase, Studio One, Reaper, Bitwig, or any AU/VST3 host
- RAM: 4 GB minimum
- Disk Space: ~30 MB
Installation Steps
macOS
- Download NIVIEM Phase One from the official website
- Extract the archive
- Copy the plugins to:
- AU:
~/Library/Audio/Plug-Ins/Components/Niviem Phase One.component - VST3:
~/Library/Audio/Plug-Ins/VST3/Niviem Phase One.vst3
- AU:
- Restart your DAW
- Scan for new plugins if required
Manual Installation (Terminal):
# Copy AU plugin
cp -r "Niviem Phase One.component" ~/Library/Audio/Plug-Ins/Components/
# Copy VST3 plugin
cp -r "Niviem Phase One.vst3" ~/Library/Audio/Plug-Ins/VST3/
Note: The plugin is code-signed and notarized by Apple. If macOS shows a security warning, go to System Settings > Privacy & Security and click "Open Anyway".
Windows
Prerequisites: Windows users must have Microsoft WebView2 Runtime installed. This is pre-installed on Windows 11 and most Windows 10 systems. If needed, download from: https://developer.microsoft.com/en-us/microsoft-edge/webview2/
- Download NIVIEM Phase One from the official website
- Extract the archive
- Copy
Niviem Phase One.vst3to:- VST3:
C:\Program Files\Common Files\VST3\
- VST3:
- Restart your DAW
- Scan for new plugins if required
Note: Windows may show a SmartScreen warning for unsigned software. Click "More info" → "Run anyway" to proceed.
Verifying Installation (macOS)
To verify the AU plugin is correctly installed:
auval -v aufx Nps1 Nivm
You should see "AU VALIDATION SUCCEEDED" at the end of the output.
Getting Started
Quick Start
- Insert NIVIEM Phase One on an audio track (guitar, keyboards, synths, vocals, etc.)
- Click one of the three speed buttons: SLOW, MEDIUM, or FAST
- That's it! The authentic PS-1A phaser sound is now applied to your audio.
Signal Flow
Input Signal → 6-Stage All-Pass Cascade → Mix with Dry → DC Blocking → Output
↑
Triangle LFO
(Speed Ramping)
The plugin processes your audio through six cascaded first-order all-pass filters. The break frequency of these filters is modulated by a triangle wave LFO, creating the characteristic sweeping effect. The processed (wet) signal is mixed with the dry signal based on the Depth control.
User Interface Overview
The NIVIEM Phase One interface features a dark industrial chassis with backlit controls and period-accurate Lowrey-style speed buttons.
Layout Organization
┌─────────────────────────────────────────────────────────────────────────┐
│ HEADER BAR │
│ [NIVIEM] PHASE ONE │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────┐ │
│ │ LFO PANEL │ │
│ │ ● │ ← Animated dot (color = speed) │
│ └─────────────┘ │
│ │
│ ┌─────────┐ ┌─────────┐ ┌─────────┐ │
│ │ SLOW │ │ MEDIUM │ │ FAST │ │
│ │ (Blue) │ │(Yellow) │ │ (Red) │ │
│ └─────────┘ └─────────┘ └─────────┘ │
│ │
│ ┌─────────────────────────────────┐ │
│ │ DEPTH KNOB │ │
│ │ (●) │ │
│ └─────────────────────────────────┘ │
│ │
│ ┌─────────────────┐ ┌─────────────────┐ │
│ │ SYNC Toggle │ │ VINTAGE Toggle │ │
│ └─────────────────┘ └─────────────────┘ │
│ │
├─────────────────────────────────────────────────────────────────────────┤
│ FOOTER BAR │
│ BYPASS [●] Phase One │
└─────────────────────────────────────────────────────────────────────────┘
Visual Elements
- LFO Dot: Animated indicator showing LFO position
- Blue when Slow is selected
- Yellow when Medium is selected
- Red when Fast is selected
- Speed Buttons: Backlit glow when active
- Depth Tooltip: Shows exact value (0-100%) on hover
- Bypass LED: Illuminates when effect is active
Operating Modes
NIVIEM Phase One offers two operating modes to suit different workflows:
Vintage Mode (Authentic)
When Vintage Mode is enabled:
| Feature | Behavior |
|---|---|
| Depth | Locked to 100% (1:1 dry/wet mix) |
| Tempo Sync | Disabled |
| Processing | Byte-for-byte identical to original PS-1A |
| Parameter Smoothing | None (authentic) |
| Bypass | Instant pass-through |
Use Vintage Mode when:
- You want 100% authentic PS-1A sound
- You're recreating classic recordings
- You need mono compatibility (no phase issues when summed)
Modern Mode (Enhanced)
When Vintage Mode is disabled:
| Feature | Behavior |
|---|---|
| Depth | Adjustable 0–100 % |
| Tempo Sync | Available — 15 musical divisions (1/32 – 4/1, triplets, dotted) |
| Continuous Rate | 0.05 Hz – 12 Hz (Modern Free) with skew for slow rates |
| Stereo Spread | 0 – 100 % (100 % = 180° L/R LFO offset) |
| Output Gain | -12 dB to +12 dB linear trim |
| Processing | Same six-stage cascade as Vintage, with parameter smoothing |
| Parameter Smoothing | 20 ms for click-free changes |
| Bypass | Crossfade for smooth transitions |
Use Modern Mode when:
- You need more subtle phasing (lower Depth)
- You want tempo-locked LFO for rhythmic effects (15 divisions including triplets)
- You want a continuous Rate knob anywhere between the preset speeds
- You want a wide modern stereo image via Stereo Spread
- You need smooth parameter automation
The Modern path runs the same six-stage cascade as Vintage. With Depth at 100 % and Spread at 0 % it produces an audibly identical mix to Vintage — just with parameter smoothing and a crossfade bypass on top.
Controls Reference
Speed Buttons
| Button | Color | LFO Rate | Cycle Time | Character |
|---|---|---|---|---|
| SLOW | Blue | 0.5 Hz | ~2 seconds | Gentle, breathing sweep |
| MEDIUM | Yellow | 1.0 Hz | 1 second | Classic phaser pulse |
| FAST | Red | 6.0 Hz | ~166ms | Vibrato-like warble |
Click any button to select that speed. The LFO will ramp to the new speed (Leslie-style).
Depth Knob (Modern Mode Only)
Range: 0% - 100% Default: 100%
Controls the wet/dry mix of the phaser effect.
| Depth | Result |
|---|---|
| 0% | Dry signal only (no phasing) |
| 50% | Subtle phasing, prominent dry |
| 100% | Full phasing (authentic PS-1A) |
Note: In Vintage Mode, Depth is locked to 100%.
Sync Toggle (Modern Mode Only)
Options: Off (Free) / On (Tempo) Default: Off
When enabled, the LFO rate locks to your DAW's tempo. The note value the cycle is anchored to is selected with the DIVISION chip immediately below the SYNC chip.
Note: In Vintage Mode, Sync is disabled (the original PS-1A had no host BPM concept).
Division Chip (Modern Mode, Tempo Sync only)
Default: 1/4 (one full LFO cycle per beat)
Click the DIVISION chip to open the Tempo Division picker — a categorised modal listing 15 musical note values:
| Group | Divisions |
|---|---|
| FAST | 1/32, 1/16T, 1/16, 1/8T, 1/8 |
| MEDIUM | 1/8., 1/4T, 1/4, 1/4., 1/2T |
| SLOW | 1/2, 1/2., 1/1, 2/1, 4/1 |
Triplet figures (T) divide a beat into three rather than two; dotted figures (.) extend the duration by 50 %. The DIVISION chip is dimmed and inactive when Sync is OFF or Vintage Mode is ON.
RATE Knob (Modern Mode, Free only)
Range: 0.05 Hz to 12 Hz Default: 0.5 Hz (matches the Slow rocker preset)
A continuous LFO rate dial that complements the three Speed rockers. Use the rockers to snap to the authentic preset speeds, then fine-tune with the knob — or drag the knob freely to anywhere in between.
| RATE Position | Rate (approx.) | Character |
|---|---|---|
| Lower travel | 0.05 – 1 Hz | Slow drift to gentle pulse |
| Middle | 1 – 3 Hz | Classic phaser pulse and faster |
| Upper travel | 3 – 12 Hz | Vibrato and tremolo territory |
The knob is dimmed and inactive in Vintage Mode (which uses the authentic preset table) and in Tempo Sync (where the rate is locked to host BPM via Division). Clicking a rocker snaps the knob to that rocker's preset Hz; dragging the knob away from a preset clears the rocker active highlight.
Stereo Spread Knob (Modern Mode Only)
Range: 0 % to 100 % Default: 0 % (mono compatible)
Offsets the LFO phase between the left and right channels. At 0 % both channels share the same LFO and the output folds cleanly to mono — exactly the behaviour of the original PS-1A. As the value rises, the right channel's LFO is shifted further out of phase from the left, creating a progressively wider stereo image.
| Spread | LFO Offset | Image |
|---|---|---|
| 0 % | 0° | Mono compatible (authentic) |
| 50 % | 90° | Spacious, still translates well to mono |
| 100 % | 180° | Maximum width — notches sweep oppositely |
In Vintage Mode this knob is forced to 0 % and dimmed.
Output Gain Knob
Range: -12 dB to +12 dB Default: 0 dB
A clean linear-gain trim applied after the phasing path. Use it to compensate for the small level shift at extreme settings, or to push the output into a downstream stage. Active in both Vintage and Modern modes.
Vintage Toggle
Options: Off (Modern) / On (Vintage) Default: Off
Switches between Modern and Vintage operating modes. See Operating Modes for details.
Bypass
Options: Off / On Default: Off
- Vintage Mode: Instant pass-through (no crossfade)
- Modern Mode: Smooth crossfade bypass
Speed Controls
SLOW (Blue Button) - 0.5 Hz
The Slow setting creates a gentle, breathing effect with a full sweep taking approximately 2 seconds.
Best for:
- Subtle pad and ambient textures
- Slow, emotional ballads
- Adding gentle movement to sustained chords
- Classic 70s keyboard sounds
Character:
- Relaxed, meditative quality
- Notches sweep slowly through the spectrum
- Adds depth without being distracting
MEDIUM (Yellow Button) - 1.0 Hz
The Medium setting is the "classic" phaser sound - a balanced 1-second sweep that works in almost any context.
Best for:
- Classic rock guitar rhythm parts
- Funk and R&B rhythm guitar
- Keyboard textures
- General-purpose phasing
Character:
- The quintessential phaser sound
- Musical and versatile
- Works with most tempos (60-120 BPM)
FAST (Red Button) - 6.0 Hz
The Fast setting creates a vibrato-like warble effect, with the sweep completing approximately 6 times per second.
Best for:
- Vibrato-style effects on guitar or keys
- Psychedelic and experimental textures
- Creating tension and urgency
- Special effects and transitions
Character:
- Intense, almost tremolo-like
- Creates a shimmer or wobble
- Best used sparingly for dramatic effect
Speed Ramping Behavior
One of the most distinctive features of the PS-1A is its Leslie-style speed ramping. When you switch between speeds:
- The LFO doesn't instantly jump to the new rate
- Instead, it smoothly accelerates or decelerates
- The time constant is approximately 0.5 seconds
- After about 1.5 seconds, the new speed is reached
This creates the same expressive quality as a Leslie speaker's horn speeding up or slowing down. Use this musically:
- Switch from SLOW to FAST right before a chorus for a dramatic build
- Switch from FAST to SLOW at the end of a section for a "winding down" effect
- Automate speed changes in your DAW for evolving textures
Preset Browser
The header preset cluster carries the active preset name and a set of compact navigation controls. Clicking the preset name opens the Preset Browser, a categorised picker covering both the factory bank and any user presets you save.
Preset Chip
Shows the name of the currently loaded preset. When the parameters drift away from the saved state — i.e. you start dialling controls — an amber asterisk appears next to the name to indicate the preset has been modified. The asterisk clears the moment a preset is reloaded or saved.
Navigation Arrows ◀ ▶
Step through the combined factory + user list one preset at a time. The list wraps at both ends, so pressing ▶ at the last preset returns you to the first.
SAVE Button
Opens a small naming prompt. Type a name and press Enter (or click Save) to write the current parameter state to disk as a .preset XML file. The file lives under your user data folder:
| Platform | Path |
|---|---|
| macOS | ~/Library/Application Support/Niviem/Niviem Phase One/Presets/ |
| Windows | %APPDATA%\Niviem\Niviem Phase One\Presets\ |
Saving a preset under the same name as an existing user preset overwrites the file.
Browser Modal
Clicking the preset chip opens the full browser. Factory presets are grouped by category; user presets, if any, appear in their own section at the end. Hovering over a user preset reveals a small Delete button on the right side of the row.
The 30 factory presets cover the common phaser idioms:
| Category | Description |
|---|---|
| Init | Neutral starting point |
| Subtle | Gentle motion for mix enhancement |
| Classic | Authentic 70s PS-1A character at preset rates |
| Modern | Continuous Rate + Stereo Spread combinations |
| Synced | Tempo-locked variations across common note values |
| Vintage | Bit-faithful PS-1A recreations with Vintage Mode engaged |
| Creative | Wild and expressive — telephone, helicopter, underwater |
Press Escape, click outside the dialog, or pick an entry to close the browser.
A/B Compare
A pair of header buttons sit to the left of the preset cluster. They give you two independent parameter snapshots — slot A and slot B — that you can compare on the fly without losing your work in either.
Toggle Button (A / B)
Shows the active slot. Click to swap. The plugin captures whatever you have dialled in into the slot you are leaving, then restores the other slot's state. So you can:
- Dial in a sound (slot A is active by default)
- Click the toggle — slot B is now active and shows whatever you saved last to B (initially the same as A)
- Edit the controls — your changes accumulate in slot B
- Click toggle again — you are back in slot A with your original sound, untouched
Both slots carry the full plugin state: speed, rate, depth, sync, division, spread, output, vintage, and bypass.
Copy Button (A→B / B→A)
The label flips to match the active slot's direction. Click to clone the current slot's state into the other slot — useful for "I like this; let me explore variations from the same starting point in the other slot."
The copy is destructive on the destination slot only; the source slot is unchanged.
Nivipedia — In-Plugin Encyclopedia
Nivipedia is the built-in encyclopedia for Phase One. It opens from the NIVI button in the header and lives directly inside the plugin window — a cream-paper documentation panel sliding out of the same chassis you're playing.
Articles
Thirty-one articles span seven categories:
| Category | Coverage |
|---|---|
| Phase One | Overview, what makes it special |
| Controls | Every knob, chip, rocker and button on the chassis |
| Modes | Vintage / Modern path differences and use cases |
| DSP Theory | All-pass filters, notch generation, triangle LFO, ramping |
| History | The Maestro PS-1A, Tom Oberheim, notable users |
| Presets | Factory bank breakdown by category |
| Workflow | Recipes — That Lady, classic 70s, ethereal pads, vibrato |
Each article carries a short brief, longer body with headings and lists, Tip / Warning call-outs where relevant, and a Related Topics row at the bottom for quick navigation.
Right-Click on any Control
Every knob, chip, rocker and button on the chassis carries two right-click affordances:
- Reset to Default — restores that control to its factory default value (e.g. Depth → 100 %, Output → 0 dB)
- What is this? — opens Nivipedia at the matching entry
The browser's own context menu (Inspect Element, image-saving, etc.) is suppressed across the whole plugin, so the only menu that appears on right-click is the plugin's own.
Search
The Nivipedia header carries a search field. Typing filters the sidebar by article title and brief; matching categories auto-expand so you can see results in context.
Tips & Techniques
Classic 70s Phaser Guitar
- Enable Vintage Mode
- Set speed to MEDIUM
- Use a clean or slightly overdriven guitar tone
- Play rhythm chords with light strumming
- The phaser adds movement without overwhelming the fundamental tone
"That Lady" Guitar Sound
To recreate Ernie Isley's iconic phased guitar tone:
- Enable Vintage Mode
- Use a humbucker guitar with moderate overdrive
- Set speed to MEDIUM
- Play funky rhythmic patterns
- Let the phaser sweep interact with your playing dynamics
Ethereal Keyboard Pads
- Enable Vintage Mode
- Set speed to SLOW
- Apply to electric piano, organ, or synthesizer pads
- Use sustained chords
- The gentle sweep adds dimension and life to static sounds
Vibrato Effect
- Enable Vintage Mode
- Set speed to FAST
- Works especially well on single-note lines
- Creates a shimmering, pitch-modulation-like effect
- Good for psychedelic leads
Subtle Modern Phasing
- Disable Vintage Mode
- Set Depth to 30-50%
- Set speed to SLOW or MEDIUM
- Great for adding gentle movement without obvious phasing
- Works well on vocals and acoustic instruments
Tempo-Synced Effects
- Disable Vintage Mode
- Enable Sync
- Choose speed based on desired rhythmic division
- Great for electronic and modern productions
- LFO stays locked to song tempo changes
Automated Speed Changes
In your DAW, automate the speed parameter for evolving effects:
Verse: SLOW (0)
Pre-Chorus: MEDIUM (1) - automation point
Chorus: FAST (2) - automation point
The smooth ramping makes these transitions musical rather than jarring.
Stereo Enhancement
NIVIEM Phase One applies the same modulation to both channels (mono-compatible). This means:
- No phase issues when summed to mono
- Consistent phasing across the stereo field
- Perfect for broadcasts and mono playback systems
Parameter Reference
User-Adjustable Parameters
| Parameter | Values | Default | Description |
|---|---|---|---|
| Speed | Slow, Medium, Fast | Slow | LFO speed preset |
| Depth | 0–100 % | 100 % | Wet / dry mix (Modern mode only) |
| Sync | Off / On | Off | Tempo sync enable (Modern mode only) |
| Sync Division | 1/32 … 4/1 (15 entries) | 1/4 | Note value the sync cycle is anchored to |
| Rate | 0.05 – 12 Hz | 0.5 Hz | Continuous LFO rate (Modern Free only, skewed for low rates) |
| Stereo Spread | 0–100 % | 0 % | L/R LFO phase offset (Modern mode only, 100 % = 180°) |
| Output Gain | -12 dB to +12 dB | 0 dB | Linear post-phaser trim |
| Vintage | Off / On | Off | Vintage mode enable |
| Bypass | Off / On | Off | Effect bypass |
Internal Parameters
| Parameter | Value | Description |
|---|---|---|
| LFO Slow Rate | 0.5 Hz | Triangle wave frequency for Slow mode |
| LFO Medium Rate | 1.0 Hz | Triangle wave frequency for Medium mode |
| LFO Fast Rate | 6.0 Hz | Triangle wave frequency for Fast mode |
| All-Pass Stages | 6 | Number of cascaded filter stages |
| Notches | 3 | Number of frequency notches created |
| Break Freq Min | 20 Hz | Minimum all-pass break frequency |
| Break Freq Max | 5000 Hz | Maximum all-pass break frequency |
| Ramp Time Constant | 0.5 s | Leslie-style speed ramping tau |
| Dry/Wet Mix (Vintage) | 50/50 | Fixed 1:1 mix in Vintage mode |
Technical Specifications
Audio
| Specification | Value |
|---|---|
| Sample Rates | 44.1 kHz - 192 kHz |
| Bit Depth | 32-bit float processing |
| Internal Precision | 64-bit coefficient calculation |
| Latency | 0 samples (zero-latency) |
| Channels | Stereo (same modulation, independent states) |
Filter
| Specification | Value |
|---|---|
| Topology | 6-stage cascaded first-order all-pass |
| Transfer Function | H(z) = (a₁ + z⁻¹) / (1 + a₁·z⁻¹) |
| Coefficient Formula | a₁ = (tan(π·fb/fs) - 1) / (tan(π·fb/fs) + 1) |
| Break Frequency Range | 20 Hz - 5000 Hz (logarithmic) |
| Notch Count | 3 (N/2 where N = 6 stages) |
LFO
| Specification | Value |
|---|---|
| Waveform | Triangle |
| Frequency Range | 0.5 Hz - 6.0 Hz (presets) |
| Speed Ramping | First-order exponential (τ = 0.5s) |
| Phase Accumulator | Sample-accurate, drift-free |
Processing Quality
| Feature | Implementation |
|---|---|
| Denormal Prevention | DC offset on filter state variables (1e-18) |
| Nyquist Protection | Coefficient clamped at 0.49 normalized frequency |
| DC Blocking | 20 Hz first-order highpass on output |
| Thread Safety | Atomic parameters for lock-free audio processing |
| Parameter Smoothing | 20ms exponential (Modern mode only) |
The Science of Phasing
How Phase Shifters Work
A phaser works by splitting the audio signal into two paths:
- Dry Path: The original signal passes through unchanged
- Wet Path: The signal passes through all-pass filters that shift phase
When these paths are recombined, frequencies where the phase shift equals 180° (plus multiples of 360°) experience destructive interference, creating notches in the frequency spectrum.
All-Pass Filters
Unlike low-pass or high-pass filters, all-pass filters pass all frequencies with unity gain but introduce a frequency-dependent phase shift.
First-Order All-Pass Transfer Function:
s - ωb
H(s) = ───────
s + ωb
Where ωb is the "break" or "corner" frequency.
Phase Response:
φ(ω) = π - 2·arctan(ω/ωb)
- At DC (ω = 0): Phase shift = 180°
- At break frequency (ω = ωb): Phase shift = 90°
- At high frequency (ω → ∞): Phase shift = 0°
Logarithmic Frequency Mapping
The break frequency is swept using logarithmic interpolation:
breakFreq = minFreq × (maxFreq / minFreq)^normalized
Where normalized is the LFO output mapped from [-1, +1] to [0, 1].
This is perceptually linear because human hearing perceives frequency logarithmically (each octave is a doubling of frequency).
Notch Generation
When dry and wet signals are mixed 1:1, notches occur where:
Total Phase Shift = 180° + n × 360° (where n = 0, 1, 2, ...)
As the LFO sweeps the break frequency, these notches move through the spectrum, creating the characteristic "swooshing" sound.
Troubleshooting
Plugin Not Appearing in DAW
- Verify the plugin is in the correct folder:
- AU:
~/Library/Audio/Plug-Ins/Components/ - VST3:
~/Library/Audio/Plug-Ins/VST3/
- AU:
- Rescan plugins in your DAW preferences
- On macOS, check System Preferences > Security & Privacy if the plugin is blocked
- Run
auval -v aufx Nps1 Nivmto verify AU installation
No Audible Effect
- Ensure the plugin is not bypassed
- Verify input signal is present (check input meter in DAW)
- Check that the track is not muted
- Check Depth is above 0% (Modern mode)
- The phaser effect is subtle at some speeds - try FAST for the most obvious effect
Effect Sounds Wrong
- Ensure the source material has frequency content in the sweep range (20 Hz - 5 kHz)
- Very dark or very bright sources may not phase effectively
- The effect is most obvious on harmonically rich material (distorted guitar, organ, etc.)
- Try enabling Vintage Mode for authentic PS-1A behavior
Speed Changes Feel Instant
The PS-1A should have smooth speed ramping. If speeds change instantly:
- Ensure you have the latest version of the plugin
- The ramping time is approximately 1.5 seconds to reach 95% of target
CPU Usage Too High
The NIVIEM Phase One is highly optimized and should have minimal CPU impact. If experiencing high CPU:
- Check that you don't have hundreds of instances
- Increase your DAW's buffer size
- Disable other heavy plugins to isolate the issue
Clicks or Pops
- Increase your DAW's buffer size (try 256 or 512 samples)
- In Modern mode, parameter smoothing should prevent clicks
- In Vintage mode, rapid parameter changes may cause artifacts (authentic behavior)
- Check for automation discontinuities
Windows: WebView2 Required
If you see a message about WebView2:
- Download Microsoft WebView2 Runtime from: https://developer.microsoft.com/en-us/microsoft-edge/webview2/
- Install and restart your DAW
Credits & References
Development
Developed and published by NIVIEM AUDIO LTD — DSP and UI by Milan Vasiljev.
Primary Research Sources
-
R.G. Keen - GeoFEX
- Traced Maestro PS-1A schematic
- Technical documentation and analysis
- geofex.com
-
Patchstorage
- PS-1A/PS-1B reference measurements
- LFO rate verification
- patchstorage.com
-
FreestompBoxes.org
- Circuit analysis and discussion
- Component verification
- freestompboxes.org
-
David Morrin
- PS-1 technical notes
- JFET specifications
Technical References
- Vadim Zavalishin - "The Art of VA Filter Design" (filter theory)
- CCRMA Stanford - Phase shifter theory
- WolfSound - All-pass filter mathematics
Special Thanks
To Tom Oberheim for the original PS-1A design that revolutionized guitar effects.
To the countless artists who made the phaser a staple of recorded music.
To the vintage gear community for preserving these classic sounds and sharing knowledge.
Version History
Version 1.1.1 (May 2026)
- Hover tooltips on every parameter-bearing control — name, current value, range; live update during drag
- Premium value-input modal on knob double-click — recessed cream-LCD field with phosphor-amber numerals, range hint, amber clamp flash on out-of-range
- Square-edge chassis (period-correct rectangular rack) and FSH-1-style circular illuminated power in the footer
Version 1.1 (May 2026)
- Continuous RATE knob (Modern Free) — dial in any LFO rate from 0.05 Hz to 12 Hz; the three Speed rockers act as quick-presets that snap the knob to the authentic 0.5 / 1 / 6 Hz values
- Stereo Spread knob (Modern) — independent L/R LFO phase offset for a wide modern stereo image; mono compatible at 0 %
- Tempo Sync now offers 15 note divisions through a Klang-style picker modal, including triplets and dotted figures from 1/32 through 4/1
- Preset Browser — 30 factory presets across 7 categories (Init, Subtle, Classic, Modern, Synced, Vintage, Creative), with user save / delete / rename to disk under your user data folder
- A/B Compare in the header — instantly switch between two parameter snapshots; copy in either direction
- Output Gain trim ±12 dB
- Nivipedia — in-plugin encyclopedia with 31 articles across 7 categories; right-click any control for Reset to Default and What is this?
- Premium chassis redesign — cream faceplate with chrome-bezel phase-shift display, brass / aged-metal knob skirts, dark Bakelite caps with amber needles
- Vintage Mode signal path is bit-identical to v1.0 — every Modern feature added in this release is gated behind the Modern toggle and forced inert when Vintage is engaged
Version 1.0 (January 2026)
- Initial release
- Dual Operating Modes:
- Vintage Mode: 100% authentic PS-1A processing
- Modern Mode: Enhanced with Depth and Tempo Sync
- Authentic 6-stage all-pass filter cascade
- Three speed presets (Slow/Medium/Fast)
- Leslie-style speed ramping
- Stereo processing with mono compatibility
- Premium DSP quality:
- 64-bit coefficient calculations
- DC blocking on output
- Denormal prevention
- Parameter smoothing (Modern mode)
- Click-free bypass crossfade (Modern mode)
- WebView-based authentic UI:
- Lowrey-style speed buttons with glow
- Animated LFO indicator (color-coded)
- Depth tooltip on hover
- Full keyboard accessibility (Tab + Arrow keys)
- WCAG AA contrast compliance
Copyright © 2026 NIVIEM AUDIO LTD. All Rights Reserved.
NIVIEM is a trademark of NIVIEM AUDIO LTD, registered in England and Wales (Company No. 17217761).
Trademark Notice
NIVIEM Phase One is an independent product developed by NIVIEM AUDIO LTD. This plugin is inspired by the vintage Maestro PS-1A Phase Shifter (1971) and is designed to emulate its sound characteristics.
Maestro is a registered trademark of Gibson Brands, Inc. The original PS-1A Phase Shifter was a product of Gibson/Maestro, designed by Tom Oberheim.
This product is not affiliated with, endorsed by, or sponsored by Gibson Brands, Inc. or any of their affiliates. All product names, trademarks, and registered trademarks mentioned in this documentation are the property of their respective owners.
The use of these names is solely for the purpose of describing the sound characteristics and historical context that inspired this emulation, which is standard practice in the audio software industry.
For support: support@niviem.net