SPL PQ All Black – Mastering Equalizer
The SPL PQ All Black is a high-end five-band parametric mastering equalizer with fully recallable stepped potentiometers, selectable constant and proportional Q, and an unmatched 120V technology signal path. With sheer unlimited headroom and incredible precision, it delivers transparent and musical equalization for mastering engineers demanding absolute sonic excellence.
Key Features
- 120V Technology: Extreme headroom, transparency, and dynamic range.
- Dual 5-Band Parametric EQ: Separate left/right channel processing.
- Stepped Potentiometers: 41-step controls for precise recall.
- Constant & Proportional Q Modes: Switchable per band.
- Auto Bypass: Objective signal evaluation without manual switching.
- 1/4 Gain Mode: Reduces boost/cut range from ±20 dB to ±5 dB.
- Link Mode: Syncs settings for perfect stereo matching.
- Completely Dual Mono: Independently process two mono signals if needed.
Advanced Filter Control
Each of the five EQ bands features a dedicated frequency range for deep control:
- LF (Low Frequency): 10 Hz – 330 Hz
- LMF (Low-Mid Frequency): 33 Hz – 1 kHz
- MF (Mid Frequency): 128 Hz – 4.1 kHz
- MHF (Mid-High Frequency): 310 Hz – 10.2 kHz
- HF (High Frequency): 760 Hz – 24 kHz
Constant Q vs. Proportional Q
The Q-mode toggle allows each band to function in either Constant Q or Proportional Q mode:
- Constant Q: Maintains the amplitude regardless of bandwidth—perfect for precise frequency cuts.
- Proportional Q: Adjusts amplitude relative to bandwidth, making wider boosts more musical and controlled.
Auto Bypass – Objective Mastering
The Auto Bypass feature allows for an automatic switching between processed and unprocessed audio, helping engineers assess changes without bias. The interval time can be adjusted using a stepped control.
Advanced Stereo Control
- Link Mode: Synchronize filter settings across both channels.
- Per-Band On/Off: Each EQ band can be switched on/off independently.
- Phase Reverse: Invert phase per channel.
Mastering-Grade Precision
The PQ features fully stepped potentiometers for exact recallability—essential in a mastering workflow.
The Power of 120V Technology
SPL’s proprietary 120V SUPRA operational amplifiers provide:
- +/-60V internal voltage: Four times higher than conventional mastering EQs.
- Extreme Dynamic Range: 135 dB ensures crystal-clear processing.
- Ultra-Low THD: 0.0005% distortion at +30 dBu.
- Enhanced Transparency: Ensures phase accuracy and musical precision.
