Classic American EQ.


AQ550 3-Band Equalizer

The AQ550 faithfully captures the punch, low-frequency transparency, and ultra-tight imaging
of iconic American EQs of the late 1960’s.

Making use of Proportional Q intuitively widens the filter bandwidth at minimal settings and
narrows it at higher settings without the need for additional bandwidth controls. This unique
feature minimizes the «phase-shift» sound found in many equalizers.

The AQ550 provides reciprocal equalization at 21 points in 5 steps of boost to a maximum of
12 dB of gain at each point. The 21 equalization points are divided into three overlapping
ranges. The high and low frequency ranges are individually selectable as either peaking or
shelving, and a band-pass filter may be inserted independently of all other selected
equalization settings. Frequency ranges and boost/cut are selected by switches, and a
pushbutton «IN» switch allows the EQ to be silently introduced to the signal path. A small
toggle switch is used to insert the band-pass filter into the AQ550.

The AQ550 extends the features of the original hardware and joins the flexibility of the digital
world to the character of the analog processing. The AQ550 plugin designed from the ground
up for fast, efficient work on mid/side, stereo and the objects, the beds (fixed channels) of
immersive mixing environments.

Latest Versions

AUv3 version 3.0.0 (Jun 27, 2023)
VST2 version 3.0.0 (Jun 27, 2023)
VST3 version 3.0.0 (Jun 27, 2023)

VST2 version 3.0.0 (Jun 27, 2023)
VST3 version 3.0.0 (Jun 27, 2023)


USD 79
USD 19



Fx Selection

This module allows you to select a equalizer from four available. The equalizers are arranged in series, this allows you to process channels with different equalizers settings. For example: the first EQ is only the mid channel, the second EQ is only the side channel, the third Eq is the left and right channel. For multi-channel modes: the first Eq is only the left and right channels, the second EQ is the center channel, the third EQ is the LFE, etc.
You can rename Fx Buttons for ease of use. To rename the selected Fx button, right-click on the button.
In order to turn on the solo (listen) of the equalizer, double-click on the selected equalizer number. The equalizer in solo mode glows yellow, to exit solo mode, double-click again. For two-channel modes, only one equalizer can be solo mode. For multi-channel modes, one or more equalizers can be soloed.
To bypass Eq processing, press the selected equalizer number one click + shift. In bypass mode, the button will glow red.
You can also copy all equalizer settings to another equalizer. To do this, select the equalizer from which you want to copy the settings, then click on the copy button, then select the equalizer to which you want to copy the settings.

Input Routing
Input Routing lets you choose between 44 common channel setups, starting from Stereo up to 7.1.4 and 9.1.6. Simply select in the input routing module the channel setup that fits your track.
You can also create your own input routing profiles. 16 independent channels are available.
Click on the edit button next to the input routing selection display. Hold down the shift button and select the desired number of channels. Name selected channels in order. Then click save and name the profile.

Channels Selection
In this module, you can select (activate) the channels that the equalizer will process.



Low Frequency (LF)

Low Band Frequency
Filter types: Shelf, Bell
Default: Bell
Range: 30Hz, 40Hz, 50Hz, 100Hz, 200Hz, 300Hz, 400Hz

Low Band Gain
Range: -12dB to +12dB

Mid Frequency (MF)

Mid Band Frequency
Range: 200Hz, 400Hz, 600Hz, 800Hz, 1.5kHz, 3kHz, 5kHz Filter types: Bell

Mid Band Gain
Range: -12dB to +12dB

High Frequency (HF)

High Band Frequency
Filter types: Shelf, Bell
Default: Bell
Range: 2.5kHz, 5kHz, 7kHz, 10kHz, 12.5kHz, 15kHz, 20kHz.

High Band Gain
Range: -12dB to +12dB

Bandpass Filter (FLTR)
The FLTR switch applies a 50 Hz - 15 kHz bandpass filter to the entire signal. The bandpass filter is completely independent from the from the three main band filters.

Bell/Shelf Switches
The LF and HF bands are normally in bell mode. When the Bell/Shelf button is engaged for the band (in the darker “down” position and the LED is illuminated), the band is switched to shelving mode.

LF Shelf
When the LF Shelf button is engaged, the low frequency band is switched to shelving mode.

HF Shelf
When the HF Shelf button is engaged, the high frequency band is switched to shelving mode.




This knob controls the level of harmonics added to the signal. The distortion is mild and adds some coloration.

Phase (Polarity)
Shifts the phase by 180 degrees. Range: 0deg - 180deg

The EQ is active when the EQ IN button is engaged and its associated LED is illuminated. When this button is off, selected EQ is disabled. Please note that this button disables only the selected equalizer, the rest of the equalizers in the FX blocks are not disabled.

Output Gain
This knob is an output gain control. The available output gain range is ±24 dB.


Comp609 4


Undo and Redo functions allow undo and redo of changes made to the plug-in parameters.

A/B buttons allows you to load two independent settings and compare them quickly.

Preset Display
Factory presets are included in the plug-in installation, installed in the following locations:
Mac: Users\[user name]\Music\Red Rock Sound\RRS AQ550\Patches
Windows: C:\Users\[user name]\Documents\Red Rock Sound\RRS AQ550
You can save the current Comp settings as the Default preset. - Full Reset – is the default preset
Load button allows loading of presets not stored in the locations described above.
Save button allows for save of user presets.

Global Output Gain
Global Output Gain controls the overall output level of the plug-in output, after all equalizers.

OS x_ activates 2x, 4x or 8x oversampling, 1x disables oversampling. (note that when the HQ mode is on, CPU will be loaded more than usual).

HQ mode (HQ)
HQ mode is for oversampling, it adds a higher order antialiasing filter. It improves processing quality, but also leads to an increase of the CPU load.

? button opens info page.

D3D / OGL / CPU (Windows)
This switch allows you to choose between GUI rendering engine:
Normally, no need in switching rendering mode manually, plug-in try to initialize D3D9 then OGL (if D3D9 failed) and CPU (if OGL failed) automatically. But if you have problems with the GUI, you can manually switch and test different rendering methods at work.

This switch is available only in the Windows version of the plugin. For the Mac version, this is not necessary.

Note: Drivers of some video cards (for example, Intel Arc A380) in D3D mode adversely affect the plug-in (periodic noise or whistle), if you encounter a similar phenomenon, use OGL or CPU.

SIMD optimization
This switch enables or disables SIMD optimization, it can be used by multichannel processing with high oversampling. It is undesirable to use in mono and stereo modes, SIMD only slows down the plug-in due to the overhead of splitting the data for optimization.
(Currently in beta testing)

- In the ARM version, you can enable or disable NEON; - In the Intel version, you can enable or disable SSE2.

SIMD Windows
- In the Intel version, you can enable or disable AVX (if supported), or SSE2.

The Windows version has a limitation: if the CPU does not support FMA, then the optimization will not work, even if AVX or SSE2 is supported.

Note: Enabling/disabling SIMD is saved in the project for each plugin individually. i.e. if a specific instance of the plugin slows down, then you can enable SIMD for it, and others, if they are in the project, will not be affected by this optimization.