Signature EQ

What You Get

• 6 fully parametric bands covering the complete audible spectrum
• Real-time frequency response display with interactive node-based editing
• Preset support — save and recall settings in your host
• Optimised for live performance: zero allocation and zero locks on the audio thread

Requirements

Platform: iPhone and iPad (Universal)

Minimum iOS: 15.0

Plugin format: AUv3 Audio Unit Extension

Host app required: AU EngineCore or any AUv3 compatible host

Loading the Plugin

Follow these steps to load Signature EQ in your host:

In AU EngineCore

• Open AU EngineCore and connect your audio interface
• Tap a channel strip or bus to open its insert slots
• Tap an empty insert slot and select → SignatureEQ

In Other Hosts

In any AUv3 compatible host, look for SignatureEQ in the audio unit browser. SignatureEQ appears under the Effect category.

Frequency Response Display

The main graph shows the combined frequency response of all active bands. The horizontal axis represents frequency from 20 Hz to 20 kHz on a logarithmic scale. The vertical axis represents gain from −24 dB to +24 dB.

Grid

• Horizontal lines at 0 dB (bright) and at ±6, ±12, ±18, ±24 dB
• Vertical lines at key frequencies: 20 Hz, 50 Hz, 100 Hz, 200 Hz, 500 Hz, 1 kHz, 2 kHz, 5 kHz, 10 kHz, 20 kHz

Band Information Readout

In the top-left corner of the graph, each band's current settings are displayed in a compact readout:

• Band label (LS, F1, F2, F3, F4, HS)
• Current frequency (e.g. 1.0 kHz)
• Current gain (e.g. +3.5 dB)
• Current Q value (e.g. Q 1.00)

The selected band is highlighted in its accent colour. Inactive bands appear dimmed.

EQ Curve

The teal/green curve shows the combined frequency response of all enabled bands. The area below the curve is filled with a subtle gradient. A glow effect on the zero-dB line marks unity gain.

Band Nodes

Each of the six bands is represented by a circular node on the graph, labelled LS, F1, F2, F3, F4, or HS. Nodes are colour-coded by band for instant visual identification.

The node is positioned on the curve at the band's frequency — it follows the actual gain contributed by that band to the overall response, not just the band's gain parameter alone.

Parameters

Every band exposes three editable parameters:

Frequency

The centre frequency, corner frequency, or shelf frequency of the filter. Range: 20 Hz to 20 000 Hz. Displayed with a logarithmic scale on the graph axis.

Gain

Boost or cut in decibels. Range: −24 dB to +24 dB.

Q (Quality Factor)

Controls the width or slope of the filter response. For Peak filters, higher Q values create narrower, more surgical bands. Range: 0.10 to 20.

Q is adjustable on all band types except Low Shelf (LS) and High Shelf (HS), where it acts as a shelf slope control. On Peak bands, Q is adjusted using the pinch gesture directly on the node.

Selecting a Band

Tap anywhere near a band node to select it. The selected band is highlighted with a glow ring and its information is shown prominently in the top-left readout. Only one band can be selected at a time.

Drag — Frequency and Gain

Touch and drag a band node to adjust its frequency and gain simultaneously:

• Drag left or right to change frequency (logarithmic — the same physical distance covers more Hz at higher frequencies)
• Drag up to increase gain; drag down to decrease gain
• Both parameters can be changed in a single gesture — diagonal drags change both at once

The node follows the actual EQ curve as you drag, so it stays visually connected to the combined response rather than jumping to a fixed position.

Pinch — Q (Width)

Place two fingers on or near a band node and pinch or spread to adjust the Q value:

• Pinch inward (spread fingers together) — increases Q, making the band narrower
• Spread outward (move fingers apart) — decreases Q, making the band wider
• Q is most expressive on Peak (bell) filter bands
• Q adjustment is disabled for Low Shelf and High Shelf bands

You do not need to be perfectly centred on the node — the pinch gesture searches for the nearest visible band within a generous hit area.

Double Tap — Reset Gain

Double-tap a band node to instantly reset that band's gain to 0 dB. The frequency and Q values are preserved. This is useful for quickly bypassing the gain effect of a band without disabling it, or for comparing the original sound with the processed version.

Saving and Loading Presets

Signature EQ integrates fully with the preset system of its host application. All band parameters are exposed as automatable AUv3 parameters, so any host that supports AUv3 preset saving can store and recall complete EQ settings.

In AU EngineCore, presets can be saved per-channel or as part of a session. Refer to your host application's documentation for preset management instructions.

Preset Recall

When a preset is loaded, all six bands update instantly. The frequency response display reflects the new settings without requiring any user interaction. This includes presets loaded via automation or scene recall in the host.

Automation

All parameters are available for automation in hosts that support AUv3 parameter automation. The following parameters are exposed per band:

• Enable / Disable
• Frequency (20 Hz – 20 000 Hz)
• Gain (−24 dB to +24 dB)
• Q (0.10 – 20.00)

Start with the Low Shelf

Begin your EQ session by setting the LS band to address the low-frequency content. A gentle boost or cut at 80 Hz with a Q of 0.707 shapes the overall weight of a sound before you tackle the midrange.

Use Double Tap to A/B a Band

Double-tap a node to reset its gain to zero, then drag back up to your boost or cut. This gives you a quick before/after comparison of that band's contribution to the sound.

Pinch for Precise Q

For surgical cuts (removing a resonance or feedback frequency), set the filter type to Peak or Notch, then use the pinch gesture to increase Q before adjusting gain. A high Q gives you a narrower, more precise cut.

Combine Filter Types

Do not feel constrained by the default filter type assignments. You can set any band to any filter type at any time. For example, use F1 as a High Pass filter to clean up the bottom end, or set F4 to a Low Pass to darken a sound.

Read the Curve

The real-time frequency response display shows you the combined effect of all bands. The small readout in the top-left corner lets you verify exact values without leaving the graph. Use the curve as your guide — trust your ears, verify with your eyes.

When Reporting an Issue

If you encounter a technical issue, please include the following information in your support request:

• Device model and iOS version
• Host application name and version
• Description of the issue, including any steps to reproduce it
• Whether the issue occurs consistently or intermittently