# Naja Stereo Widener — User Manual

---

## Overview

**Naja** is a multiband stereo widening plugin designed to give precise, frequency-selective control over the stereo image of any audio signal. By splitting the signal into four independent frequency bands, Naja lets you widen, narrow, or spatially position each band independently — from the low end to the high end — while a master section, parametric EQ, and utility controls shape the final output.

Naja operates as a stereo in / stereo out plugin and is compatible with any DAW supporting VST3 or AU formats.

---

## Signal Flow

```
Stereo Input
	│
	├─► 4-Band Crossover Splitter (XO1 / XO2 / XO3)
	│       │
	│       ├─► LO Band ── Width ── IID ── ITD ── Bypass ──┐
	│       ├─► LM Band ── Width ── IID ── ITD ── Bypass ──┤
	│       ├─► HM Band ── Width ── IID ── ITD ── Bypass ──┤
	│       └─► HI Band  ── Width ── IID ── ITD ── Bypass ──┘
	│                                                        │
	│                                              Band Recombination
	│                                                        │
	├─────────────────────────────────────────────► Master Section
	│                                               (Width / Gain / Centre)
	│                                                        │
	│                                              Parametric EQ (5-band)
	│                                                        │
	│                                              Haas Delay
	│                                                        │
	│                                              Dry / Wet Mix
	│                                                        │
Stereo Output
```

---

## Interface Layout

The Naja UI is divided into four main areas:

| Area | Location | Contents |
|---|---|---|
| **Vector Scope** | Far left | Real-time stereo phase/width visualisation |
| **Band Strips** | Centre | Four per-band processing columns (LO, LM, HM, HI) |
| **Master Column** | Far right | Global output controls, EQ, crossovers, utilities |
| **Theme Toggle** | Top-left of scope | Light / Dark mode switch |

---

The Vector Scope occupies the left portion of the plugin and displays the real-time spectral content of the output signal across the full audible frequency range (20 Hz – 20 kHz).

-Two mirrored spectrum graphs are drawn back-to-back along a shared vertical centre line — the left channel extends to the left and the right channel extends to the right.
-The vertical axis represents frequency, running from low frequencies at the bottom to high frequencies at the top on a logarithmic scale.
-The horizontal axis represents amplitude — the wider the graph at any given frequency, the more energy is present in that band.
-A symmetrical shape indicates a balanced stereo image — both channels carrying similar content at each frequency.
-An asymmetrical shape indicates a difference between left and right channels at specific frequencies, reflecting active stereo widening or IID processing.
-A glowing highlight pulses along the centre line between the two graphs, reflecting the level of the shared mono/centre content — the brighter the glow, the stronger the mid signal at that point in the frequency range.
-The graphs are semi-transparent and signal-reactive — brightness and opacity increase with output level, fading when the signal is quiet.
-A correlation meter runs along the bottom of the scope area as a horizontal LED bar, showing the phase relationship between the left and right channels at a glance.
-The scope updates at 60 fps and reflects all processing applied by Naja in real time.


### Theme Toggle
Located in the **top-left corner** of the vector scope.  
- Displays **"Dark"** when dark mode is active (click to switch to light mode).  
- Displays **"Light"** when light mode is active (click to switch to dark mode).  
- The toggle is enclosed in a faint rectangular frame for visibility.

---

## Crossover Section

Three linear sliders in the master column define the four frequency bands.

| Control | Range | Default | Purpose |
|---|---|---|---|
| **Crossover 1** | 20 Hz – 2,000 Hz | 250 Hz | Sets the boundary between the LO and LM bands |
| **Crossover 2** | 200 Hz – 8,000 Hz | 2,500 Hz | Sets the boundary between the LM and HM bands |
| **Crossover 3** | 2,000 Hz – 20,000 Hz | 8,000 Hz | Sets the boundary between the HM and HI bands |

**Tips:**
- Keep crossovers in ascending order (XO1 < XO2 < XO3) to avoid undefined band boundaries.
- Set XO1 below the fundamental of your bass content to isolate the low end cleanly.
- Adjust XO2 to control where the mid presence region begins.
- Double-click any slider to return it to its default value.

---

## Band Strips (LO · LM · HM · HI)

Four identical processing columns handle each frequency band. Bands are labelled at the top of each column: **LO** (low), **LM** (low-mid), **HM** (high-mid), **HI** (high).

### Width
| Property | Value |
|---|---|
| Range | 0.0 – 2.0 |
| Default | 1.0 |
| Control type | Rotary knob |

Controls the stereo width of this band.

- **0.0** = fully mono (L and R summed to centre).
- **1.0** = unity — stereo image is unchanged.
- **2.0** = fully exaggerated stereo width.

Use narrow values on low frequencies to keep the bass focused and phase-coherent, and wider values on upper-mid / high bands for air and presence.

---

### IID (Inter-aural Intensity Difference)
| Property | Value |
|---|---|
| Range | −12 dB – +12 dB |
| Default | 0 dB |
| Control type | Rotary knob |

Applies a gain difference between the left and right channels of this band, simulating the natural level difference that creates the perception of lateral positioning.

- **Positive values** push the image to the right.
- **Negative values** push the image to the left.
- **0 dB** = centre (no panning).

IID is useful for nudging specific frequency ranges left or right without affecting overall panning.

---

### Delay (ITD — Inter-aural Time Difference)
| Property | Value |
|---|---|
| Range | 0 ms – 15 ms |
| Default | 0 ms |
| Control type | Rotary knob |

Introduces a short time delay between the left and right channels of this band, simulating the arrival-time difference that the human auditory system uses to localise sound sources.

- Small values (1–3 ms) add subtle width and space.
- Larger values (5–15 ms) create a strong sense of lateral displacement.
- At high settings, comb-filtering and phase issues may occur — use by ear.

---

### Bypass
A small pill-shaped LED toggle at the bottom of each band strip.

- **Off (unlit):** the band's Width, IID, and ITD processing is active.
- **On (lit cyan):** the band is bypassed and passes through unprocessed at unity gain.

Use bypass to A/B a band's processing without adjusting its parameters.

---

## Master Column

The master column on the right side of the plugin contains global output controls that affect the full mixed signal after band recombination.

---

### Preset Box
A small display at the very top of the master column showing the **current preset name**.  
- Click to open the preset menu (load / save presets).
- The default preset name is **"Initial"**.

---

### Mono ↔ Stereo Toggle
A labelled toggle strip below the preset box.

- **Mono → Stereo:** Folds the input down to mono before processing, then distributes it across the stereo field. Useful when processing mono sources such as vocals, bass, or drum overheads recorded in mono.
- **Stereo (default):** Passes the stereo input through normally.

---

### Master Gain
| Property | Value |
|---|---|
| Range | −24 dB – +24 dB |
| Default | 0 dB |
| Control type | Rotary knob |

Global output gain applied after all band processing and recombination.  
Use this to compensate for any overall level change introduced by the stereo widening.

---

### Master Width
| Property | Value |
|---|---|
| Range | 0.0 – 2.0 |
| Default | 1.0 |
| Control type | Rotary knob |

A global width multiplier applied to the fully recombined signal, on top of any per-band width settings.

- **0.0** = mono.
- **1.0** = unity.
- **2.0** = maximum widening.

Think of this as a "final width trim" after all per-band decisions have been made.

---

### Centre Channel
| Property | Value |
|---|---|
| Range | −24 dB – +24 dB |
| Default | 0 dB |
| Control type | Rotary knob |

Controls the level of the mid (centre) component of the stereo signal independently of the sides.

- Increase to bring forward vocals, kick, or bass anchored in the centre.
- Decrease to de-emphasise the mono content and push the stereo sides forward.

The small **pill toggle** above the Centre knob enables or disables centre-channel processing entirely.

- **On (lit):** Centre level control is active.
- **Off (unlit):** Centre channel is passed through at its natural level.

---

### Dry / Wet
| Control | Range | Default |
|---|---|---|
| **Dry** | 0.0 – 1.0 | 0.0 |
| **Wet** | 0.0 – 1.0 | 1.0 |

Two knobs below the main master row control the blend between the original (dry) signal and the fully processed (wet) output.

- **Dry = 0, Wet = 1** (default): full processed signal, no dry blend.
- **Dry = 1, Wet = 1**: parallel processing — original signal mixed with processed output (useful for subtle widening).
- **Dry = 1, Wet = 0**: bypass equivalent — original signal only.

The small **pill toggle** between the two knobs enables or disables the Dry/Wet section.

- **On (lit):** Dry/Wet mixing is active.
- **Off (unlit):** Only the wet (processed) signal passes through at full level.

---

## Parametric EQ

A 5-band parametric EQ sits below the band-strip controls. Bands are selected using the **five rectangular buttons** immediately below the EQ curve display.

### EQ Band Selection Buttons
Five buttons, one per band, with approximate centre frequencies:
| Band | Default Centre Freq |
|---|---|
| 1 | 80 Hz |
| 2 | 250 Hz |
| 3 | 1,000 Hz |
| 4 | 4,000 Hz |
| 5 | 12,000 Hz |

Click a button to select it — its three control knobs become active.

---

### EQ Gain
| Property | Value |
|---|---|
| Range | −12 dB – +12 dB |
| Default | 0 dB |

Boost or cut the selected band.

---

### EQ Freq
| Property | Value |
|---|---|
| Range | Band-dependent (see table above) |
| Default | Band centre frequency |

Moves the centre frequency of the selected band within its range (logarithmic scaling).

---

### EQ Q
| Property | Value |
|---|---|
| Range | 0.1 – 10.0 |
| Default | 1.4 |

Controls the width of the EQ band.

- **Low Q (0.1–0.5):** Broad, gentle shelf-like curve.
- **Medium Q (0.7–2.0):** Standard parametric bell shape.
- **High Q (3.0–10.0):** Very narrow, surgical boost or cut.

---

## Phase Invert Section

Four **INVERT** buttons appear in the master column, one per frequency band (LO, LM, HM, HI). Each button inverts the phase of the corresponding band's output.

- **Off:** Normal phase.
- **On (lit cyan):** Phase of that band is inverted by 180°.

Use phase invert to correct phase cancellation introduced by processing, or creatively to alter inter-band coherence.

---

## Haas Delay
| Property | Value |
|---|---|
| Range | 0 ms – 15 ms |
| Default | 10 ms |
| Control type | Linear slider |

Applies a global Haas (precedence effect) delay to one side of the stereo output. Delays of up to ~35 ms between ears cause the brain to perceive spatial width or position without perceiving a distinct echo.

- **0 ms:** No Haas effect.
- **1–5 ms:** Subtle widening, generally transparent.
- **5–15 ms:** Pronounced spatial effect; may colour the stereo image.

> **Note:** Heavy Haas delay can cause mono compatibility issues. Check your mix in mono when using significant values.

---

## Preset Management

Naja includes a simple file-based preset system.

- The **preset box** at the top of the master column displays the current preset name.
- **Click** the preset box to open the preset menu.
- Presets are saved as files on disk and can be shared between sessions and machines.
- Double-clicking any knob resets it to its **default value**.

---

## UI Controls Reference

| Interaction | Action |
|---|---|
| **Click + drag** a knob | Adjust value |
| **Double-click** a knob | Reset to default |
| **Right-click** a knob | Open value entry box (type exact value) |
| **Click** a band button | Select EQ band |
| **Click** a bypass / toggle pill | Enable / disable |
| **Click** preset box | Open preset menu |
| **Click** theme toggle | Switch Light / Dark mode |

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## Tips & Best Practices

1. **Start with crossovers.** Set XO1, XO2, and XO3 to match the natural frequency content of your source before touching width or IID.

2. **Keep LO band narrow or at unity.** Wide low frequencies cause mono compatibility issues and can make the low end feel vague and unfocused.

3. **Use IID sparingly.** Large IID values create obvious panning rather than natural widening. ±3 dB is a typical range for subtle spatial placement.

4. **Combine ITD and Width for depth.** A small ITD (1–3 ms) with a moderately wide Width setting produces a convincing sense of acoustic space.

5. **Use the Vector Scope constantly.** Watch for excessive horizontal spread (phase cancellation) especially on the LO band.

6. **Check in mono.** Enable your DAW's mono fold-down regularly to ensure your low-end and centre content survives.

7. **Use Dry/Wet for parallel widening.** Setting Dry and Wet both to moderate values blends the widened signal with the original, preserving transient punch while adding space.

8. **EQ after widening.** The 5-band EQ sits post-processing, making it ideal for tonal correction after the stereo image has been shaped.

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## Specifications

| Property | Value |
|---|---|
| Plugin formats | VST3 / AU |
| Channels | Stereo in / Stereo out |
| Latency | Minimal (crossover filter delay only) |
| Sample rates | All standard rates supported |
| Parameter automation | Fully supported (all knobs and toggles) |
| Preset format | File-based (.naja) |

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*Naja Stereo Widener — User Manual*  
*© Dalk Audio. All rights reserved.*
