## Technical Description of the YS-Stereo Makeup Plugin (for DAW User Documentation)

### Purpose
YS-Stereo Makeup is an audio plug-in for shaping the stereo field and adding ambience to a signal. It is designed for use in a DAW on individual tracks (instruments, vocals, groups) or on subgroups and the master bus. It provides multi-band control over width, phase relationships, and stereo depth, with Mid/Side processing, built-in light reverb, and quick configuration search tools.

---

### Processing Architecture

- **Four-band crossover structure**: the frequency spectrum is divided into four bands by crossovers; each band is processed independently. - **Narrow Mode (2 Narrow Bands)**: Three of the four bands (Wide) can be further divided into two narrower frequency sections; one section is sent to the left channel, the other to the right, creating a psychoacoustic widening effect without significantly changing the timbre.
- **Bass Band**: Wide Stereo / Mono switch; Mono+Bass mode additionally affects the direct (Dry) signal, keeping the low-frequency foundation centered and avoiding mono compatibility issues.

---

### Phase Processing

- **Phase Shift**: A phase-shifting effect is added to the signal in parallel — left channel: -90°, right channel: +90°.
- **Control Modes**: Effect adjustments can be made separately for the left/right channels or in Mid/Side mode (Mid is the center channel, Side is the side channels).
- **Purpose**: Width correction, creation of spatial effects, and phase coherence control without radically altering the spectral balance.

---

### Depth and Width Control

- **Haas Knob**: Adds a delay in the range of 0–30 ms to enhance perceived depth; used as a tool for creating stereo "depth" without significantly widening the width.
- **Wide**: Adjusts the volume of the side channels of the original (Dry) signal.
- **Side**: Adjusts the volume of the side channels of the processed (FX) signal.
- **FX**: Global effect amount control that maintains the relative ratios of the parameters set in the individual bands.

---

### Output Level and Monitoring

- **Gain**: Adjusts the overall output volume based on LUFS metrics; designed for integrating the plugin into professional mixing chains with long-term loudness control. - **Mute Dry / Mute FX**: Separate mute buttons for the direct (dry) signal and the effect signal for A/B comparison and evaluating the effect's contribution.
- **Mid/Side Monitoring**: The FX monitoring buttons allow you to listen to the center (Mid) and side (Side) channels with the effect separately; useful for identifying phase issues and checking mono compatibility.

---

### Built-in Reverb

- **Verb (Feedback)**: Adjusts the reverb duration (decay time).
- **Vol**: Adjusts the reverb volume.
- **Purpose**: Light spatial processing for "gluing" the stereo field or gently expanding the ambience without the need for a separate reverb plugin.

---

### Level Metering (VU Meters)

- **White VU Meters**: Display the signal level in the left and right channels (L/R). These meters allow you to monitor peak and average dynamics across stereo channels and make timely gain adjustments to avoid clipping.
- **Green VU Meters**: Display the level of the center (Mid) and side (Side) channels. These meters provide a visual assessment of the balance between the center and sides, help identify excessive stereo widening or center dips, and evaluate mono compatibility.

---

### Controls and Usability

- **Band On/Off**: A separate switch for each band allows you to isolate the influence of a specific frequency region.
- **Random**: Generates a random combination of settings for quickly trying out options and finding the right configuration.
- **Reset**: Resets all parameters to factory defaults.
- **Presets**: Save all processing settings, as well as custom band names and colors; ensure quick loading of proven configurations and easy project navigation.

---

### Practical Tips for Using in a DAW

- **Vocals**: Use band splitting for a subtle high-end extension, keep the lows and some mids centered; use Haas for depth and Mid/Side monitoring for center control.
- **Guitars**: Use Narrow mode in the mids for precise width control; keep an eye on the Wide/Side balance to maintain clarity.
- **Synths and Pads**: Combine phase shift and subtle reverb to create an airy sound; use green VU meters to avoid overloading the Side.
- **Master Bus**: Use sparingly, primarily in the highs; Monitor mono compatibility with Mono mode for bass and Mid/Side monitoring.
- Drums: Extend cymbals and hi-hats, keep kick and snare drum centered; white VU meters help avoid transient peaks.

---

Technical Features and Workflow Integration

- Mid/Side Processing: Allows for targeted processing of the center and sides, which is especially useful when working with vocals, guitars, synth pads, and the master bus.
- Mono Compatibility Control: Mono mode for the bass band and Mid/Side monitoring help prevent low frequencies from "dropping out" when listening in mono.
- Routing Flexibility: Dry/FX split and separate Side/Wide controls provide precise control over the balance between the original stereo field and the added processing.
- Mix Metrics Integration: LUFS-based Gain and A/B comparison capabilities make the plugin suitable for final mixing and pre-mastering.