FAIRUZOp-Amp EQP422

P422 Fairuz is a four-band equalizer built on the API design, with an op-amp for punch. Around the four bands sit two shelves, two filters, the input transformer’s sub lift and an output transformer you can switch in. The signal takes this path:

Where Fairuz comes from

Fairuz’s roots go back to the API 550 equalizer, designed by Saul Walker in the late 1960s and built into the console strips that shaped decades of recorded music. At its heart is the API 2520, a discrete op-amp whose punch, warmth and headroom under pressure defined the sound of an era. That op-amp character runs through every band in Fairuz.

P422 does not emulate any existing hardware. Every frequency point, every gain step and every curve was designed by ear, to make your instruments sound more like themselves, only better. Fairuz [Fay-rooz] is the Arabic word for turquoise.

Load P422 on a vocal, a guitar or a drum bus. A new instance loads the Default preset: all four bands on and flat, filters and shelves off, nothing driven.

The four bands run in rows down the middle of the panel: HIGH at the top, then HI-MID, LO-MID and LOW. Each row has a power LED and a frequency knob, then three shape icons and a gain control. In the visualizer each band is a numbered dot, 1 for LOW to 4 for HIGH.

Band controls

• LED: switches the band off. Its gain then drives (the drive mode, below).
• Frequency knob: the center of the band.
• Shape icons: Contour, Contour X2 and Bell, from left to right.
• Gain: ±12 dB, default 0 dB.
• Staircase icon, at the right of the gain: stepped frequency, the default, or continuous. Stepped also moves the gain in 0.5 dB steps.

Stepped or continuous

The steps sit where instruments live, chosen by ear. Switch to continuous to chase a resonance between two steps.

The three shapes

Contour is a boost and a dip beside it, in one move. The dip is tuned per band: the boost stays focused and the area around it stays clear. The peak sits a little above the knob’s frequency and the dip below it. Contour X2 is Contour with deeper, bolder shaping, for bold moves: a kick that thumps, a vocal that cuts through. Bell is wide at small gains and narrower as the gain grows; use it for problem frequencies.

Measured from P422 itself: the HI-MID band at 1 kHz, continuous frequency, the rest of the panel at the Default preset.

Resonance Hunt

Right-click a band’s frequency knob, hold, and drag. The band jumps to +12 dB while you hold, so the resonances stand out in the track. Hold Shift before the right-click for −12 dB, to find the cut that brings the most relief. Release, and the gain goes back. The help strip reads FREQUENCY HUNTING MODE while you hunt.

Band off: the drive mode

Click a band’s LED to switch it off. Its curve goes, and its gain becomes a drive control. It pushes the op-amp on the whole signal, with no boost or cut.

• Above 0 dB: punch and grit, more as you go up.
• At 0 dB: clean.
• Below 0 dB: a lighter grit than the same distance above.

With more than one band off, their drive adds up. The frequency knob and the shape icons do nothing while the band is off.

On the panel the band’s LED goes dark and a red ring glows around the band’s knob, brighter as you push the drive. In the visualizer the band keeps a dimmed dot and a dotted outline of its curve. The panel above shows both: Solo Destroyer drives with its LOW band.

The shelves

LO SHELF sits at the bottom left, HI SHELF at the bottom right. Each has a power button, a frequency knob and a gain control. LO SHELF lifts the lows and dips above its frequency, where low-mid mud lives. HI SHELF lifts the air and dips below its frequency, in the upper presence. The dip keeps the lift clean.

• LO SHELF: 20 Hz to 5 kHz, default 100 Hz.
• HI SHELF: 60 Hz to 18 kHz, default 10 kHz.
• Gain: −50 to +100, default 0. It sets how far the shelf reshapes the sound, not a dB value. Small values polish, large values change the character.

The filters

HPF before or after the Hammer

The HPF Pos switch, above the HPF, reads Pre Hammer or Post Hammer. It puts the HPF before or after the op-amp and the Hammer.

A busy low end usually wants Pre. Maximum weight wants Post.

OUT and TRIM OUT sit in the left column, TRIM OUT as the small screw to the right of OUT; VOICE sits above them. With the Hammer they set how hard the op-amp and the transformer work, and how loud the result comes out.

The OUT LED

The LED left of OUT shows the op-amp biting. Each hit holds for a moment, so a single snare hit still shows.

Drive and match in one move

Hold Shift and drag OUT or TRIM OUT: the other moves the opposite way, so the level stays put while the drive changes. Shift-Option-drag (Shift-Alt on Windows) moves both the same way.

The Hammer

The Hammer is the output transformer. Click the Hammer button at the bottom-left corner to switch it in or out.

OUT and VOICE set how hard it works. For clean weight, turn VOICE left: the body stays, the low-end grit goes.

MIX

MIX sits to the right of VOICE. It blends the dry signal into the processed one, 0 to 100 % dry. At 0, the default, you hear only the processed signal; at 100 only the dry signal. Use it for parallel processing: push the EQ and the drive hard, then blend back to keep the original transients. The visualizer always shows the processed signal.

TREMOR

TREMOR sits at the bottom center, under the LOW band. It is the input transformer’s sub-bass lift. Slide it right for more; the center of the lift rises as you go. The default is off, at the left end. The lift follows the low end of the music instead of sitting at one frequency, and it comes before the four bands, so you can tidy its weight with a LOW cut.

On headphones or with a subwoofer, you feel TREMOR. On small speakers you hear it through the bands it feeds.

Meters

The input and output meters sit in the left column, under OUT. Click either one to switch both.

The ≡ menu

Click ≡ at the right end of the top bar.

The help strip

While Tooltip is ON, the black strip at the bottom of the panel shows a line of help about the control under the pointer. During Resonance Hunt it reads FREQUENCY HUNTING MODE.

Click » at the right edge of the panel to open the visualizer, and again to close it. The white curve is the EQ you are dialing, Hammer included. Each band draws its own curve underneath, in its color. IN shows the spectrum entering P422, OUT the spectrum leaving it.

The dots

A band that is off keeps a dimmed dot and a dotted outline of its curve. With Step on, a drag follows the stepped frequencies.

The band card

Point at a dot and its card opens: name, power, frequency, gain, shape, Step and headphones. Double-click the frequency or the gain to type a value. Frequency takes Hz (1k5, 2500), a note name (A2, C#3) and, for the filters, OFF.

Solo

Click the headphones, or press S, to hear only the range the band touches. The plot dims outside it, and the icon shows S. Alt-click, or Alt-S, plays this band alone with the other EQ stages out of the way; the icon shows B. Solo follows your hand to the next band you grab. It is never saved.

IN, OUT and ANALYZER

IN and OUT switch the two spectra on and off. ANALYZER sets the rest:

Scale, keys and crosshair

• ±dB: the EQ scale, 3, 6, 12 or 26 dB. The wheel over the scale does the same.
• Keys: swaps the frequency labels for a piano keyboard, so a band reads as a note. Click a key to see what the curve does there.
• Crosshair: the pointer reads the frequency and level under it, or the nearby peak.

Gestures, and keys after a grab

The keys work only after you grab a dot, until you click away or press Escape. While you only hover, the host keeps its shortcuts.

What it remembers

Colors, the dB scale, the keys, IN, OUT and the ANALYZER settings apply to every instance in every session. A new instance opens the visualizer the way you left the last one.

Starting points, not presets. Set the controls, listen for the result, and match the level with TRIM OUT before you judge.

The panel’s shortcuts. On Linux, use the Windows keys.

The visualizer has its own gestures and keys: see Gestures, and keys after a grab, in The visualizer.

Click the preset name in the top bar to open the browser; the arrows beside it step to the previous or next preset. Folders are on the left, presets on the right. Click a preset to load it; the strip under the lists shows its note. Point at any part of the browser below.

Search, tags and notes

Type in the search field to find presets whose name, folder, note or tags contain every word. Start a word with # to search tags only, as in #vocal.

Edit description and tags writes your own note, up to 200 characters, and your own tags, separated by commas.

What a preset stores

The factory library

276 presets in sixteen folders, from Acoustic Guitar to World Strings. Every preset has a note on what it does to the track, and tags. Default and INIT sit at the top of the bank.

Where presets live

Presets are files: copy the folder to back them up. Open Preset Folder in the ≡ menu takes you there. On iPad and iPhone they live inside the app.

Run the installer for your system and choose the formats you need. Then rescan the plug-ins in your host. For iPad and iPhone, and for Linux, see their own sections.

The license

Click License Status in the ≡ menu. The window shows the status, your key, how many computers use the license, and the days left of a demo or the paid-through date.

Uninstalling

P422 is on the App Store for iPad and iPhone, iOS 15 or later, with the same sound, controls and presets. One purchase gives you both:

Touch

Turn the device sideways for the largest view. On iPhone the visualizer shows only sideways; held upright, the panel fills the screen. The App Store purchase is your license, so the menu has no License Status. In Manuals, User Guides opens these guides online.

Presets on iOS

Your presets live inside the app, shared by the plug-in and the app, and updates never touch them. Export shares a preset through the share sheet; Import brings one in from Files. Deleting the app deletes your presets: export them first. An update with a new factory library replaces only the factory presets you never changed; the ones you edited stay where they are.

P422 runs on 64-bit Intel and AMD Linux as VST3 and LV2, with glibc 2.34 or newer: Ubuntu 22.04, Debian 12, Fedora 35 or later, Arch and others. Check with getconf GNU_LIBC_VERSION. Install one form, not both:

Then rescan the plug-ins in your host; restart Ardour or Mixbus. An update never overwrites a preset: it only adds the factory presets you do not have.

VST3 or LV2

Both sound the same and share presets, settings and the license. Use the VST3 in REAPER, which cannot automate the LV2, and in Bitwig, which does not load LV2. In Ardour and Mixbus both work. In the LV2, the host’s bypass and the Bypass button are separate switches.

Activating

Click into the key field and press Ctrl-V. One activation covers both formats and every host for your account. Before you reinstall Linux, click Deactivate: a new installation may count as a new computer.

Files