Users Manual
Copyright © Synapse Audio Software 2014. All rights reserved.
Concept and Manual: Richard Hoffmann
Graphic Design: Marcin Lezak
Programming: Richard Hoffmann, Marcin Lezak
www.synapse-audio.com
GQ-7 Users Manual - 2
1. Welcome to GQ-7
Thank you for downloading the GQ-7 rack extension by Synapse Audio! This manual will give
you an overview of the features found in the GQ-7, as well as explain how to use this software.
1.1. Introduction
The Synapse GQ-7 rack extension is designed as a professional mixing and mastering equalizer,
offering five bands with high-quality parametric and shelving EQs, plus two additional low- and
high cut filters with variable slopes. The GQ-7 is suitable for a broad spectrum of tasks whether
you need an equalizer to mix instrument tracks, remove problem frequencies in your master
with surgical precision, or get rid of the mic rumble in recordings, the GQ-7 does it all, while
delivering superior results.
All filters in the GQ-7 are designed to handle modulation without artefacts, such that the EQ can
be used for creative purposes too, well outside the realm of traditional EQ applications. Especially
the low- and high cut filters are well suited for creative purposes- their unique sound offers
a great alternative to the typical sound of standard low- and high pass filters.
With Auto-gain compensation (AGC), Phase Inversion and Send Mode on board, the GQ-7
surpasses most equalizers in terms of flexibility.
The GQ-7 was designed with low CPU usage in mind, allowing to use a large number of instances
simultaneously on modern computers. Unused bands are not processed, furthermore the EQ
requires no CPU power when idle.
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2. Interface Overview
The heart of the Synapse GQ-7 is the interactive display in the center of the interface. This display
plots the frequency response from 25 Hz to 25 kHz according to the current EQ settings, thus
giving instant visual feedback of how the audio signal is going to be processed. The gain and
attenuation of all frequencies are displayed along the vertical axis of the display. The default
range is ±15 dB, by clicking on the "+" and "-" buttons on the right, the range can be increased
or decreased.
Using the interactive display is straightforward: By left-clicking and dragging the circles labeled
1 to 5, the frequency and gain of the respective EQ band can be changed directly.
The bottom part of the interface allows to turn individual EQ bands on or off, and hosts the
additional low- and high cut filters.
The top bar comprises the preset selector, as well as three additional buttons (Auto-Gain
Compensation, Phase Inversion and Send Mode).
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3. GQ-7 Parameters
The GQ-7 consists of five parametric EQ bands, labeled 1 to 5, plus two additional filters, yielding
seven filters in total. The five EQ bands can be switched between bell and shelf filters by dragging
the corresponding image up or down using the mouse.
By default, the first and last band are set to low- and high shelf filters, respectively, while bands
2, 3 and 4 are set to a bell filter.
Each parametric EQ band can be activated or deactivated using the IN button. The following
sections describe the three parametric EQ types (Bell, Low- and High Shelf), followed by the lowand high-cut filters.
3.1. Bell
The bell EQ features 3 parameters - frequency, gain and Q. Frequency and Gain can be changed
either from the interactive display, or via the corresponding knobs on the bottom panel.
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The frequency parameter sets the location of the peak of the bell curve on the frequency axis.
Gain defines how much to cut or boost that frequency, and Q adjusts the bell shape from narrow
to very broad.
Bell-shaped EQs are the most common type of EQs, due to their versatility. For instance,
parametric EQs can be used to gently boost or cut any frequency region using a low Q factor, or
they can be used to eliminate problem frequencies using a high Q and strong attenuation. They
can also be used to sweep through the mix using a high Q factor, in order to find problematic
frequencies (see "Send Mode" for more information).
3.2. Low and High Shelf
The low shelf filter is primarily designed to boost or attenuate bass frequencies, although it can
be used across the entire spectrum. The low shelf EQ features frequency, Q and gain parameters,
just like the bell-shaped EQ.
Note that if you wish to attenuate bass frequencies, consider the low-cut filter as an alternative.
In general, the low-cut filters will be much better for strong attenuation, while the low shelf filter
is preferable to obtain subtle effects.
The high-shelf filter is a mirrored version of the low shelf filter, designed to boost or attenuate
high frequencies. The filter has the same parameters as the low shelf filter.
If you wish to attenuate high frequencies, the high-cut filter is an alternative. In general, the
high-cut filters will be much better for strong attenuation, while the high shelf filter is preferable
for subtle effects.
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3.3. Low and High Cut filters
The Low Cut filter (LCF) and the High Cut filter (HCF), placed at the leftmost and rightmost side
of the GQ-7, are offered in addition to the five parametric/shelf bands. Both the LCF and the HCF
are turned off by default, in order to keep the EQ response flat and to reduce the CPU usage
a little. Be sure to enable the filter you wish to use first, or choose the "All In" preset which
activates both the LCF and HCF.
The filter parameters comprise the corner frequency given in Hz, as well as the slope given
in dB/octave. The slope can be adjusted from 12 dB to 96 dB, allowing you to go from a fairly
gentle response to a very steep response. The resonance control allows you to introduce
feedback, increasing the tone shaping options.
Both the low- and high cut filters are an excellent choice for cleaning up an instrument track,
a recording, or even an entire mix. The Low Cut filter, for example, can be used to remove
everything below 30 Hz, choosing a steep slope like 48 dB/octave or more. The High Cut filter
can be used to remove high-frequency hiss. Shelf type filters are often not suitable for this
purpose, as their slope is too gentle.
There is two types of filters, "A" and "B". The filters labeled "A" are steep filters which roll off fast,
approaching a brick-wall response. The filters labeled "B" are typical synthesizer filters, with a
gentle roll off that slowly approaches the given decibel/octave setting. For mixing and mastering,
we recommend to use the steeper filters, for creative applications both types are fine.
The low- and high cut filters are designed with CV modulation and automation in mind. The
unique sound of those filters yields a nice alternative to the typical low- and high pass filters
offered by many synthesizers and effects, especially when using steep slopes.
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3.4. Auto Gain, Phase Inversion and Send Mode
1 32
1) Auto Gain: Enabling the Auto Gain Compensation (AGC) button automatically compensates
for increase or loss of gain caused by the EQ action. Since a louder mix typically sounds better,
it is a common mistake to boost too much. Likewise, cutting frequencies may sound worse as
the mix becomes softer, even in situations where this is an improvement. The AGC option can
substantially speed up the work flow, by compensating for the volume difference after EQ'ing.
Note that the volume difference calculated by the AGC feature is an educated guess based on
the parameter settings, not a dynamic, compressor/limiter type feature. This allows the GQ-7
to process the signal in a transparent and linear way at all times, thus not distorting the transients
or overall dynamics of the signal in any way.
2) Phase Inversion: The Phase Invert button flips the polarity of the output signal. Phase
Inversions allows you to fix phase issues when mixing individual tracks. When the button is in
the lit position, the phase is reversed. Leave the switch in the disengaged position to obtain the
normal phase.
3) Send Mode: Enabling the Send Mode button subtracts the input signal from the output, such
that only the EQ band action alone is audible. Sending this output to a mix buss allows you to
apply additional non-linear effects like saturation, distortion or compression to the EQ signal,
without affecting the dry signal in any way.
Another useful application of the Send mode is to take one of the parametric EQs set to a high
Q and high gain. Now sweep this EQ across the frequency spectrum in order to find problematic
frequencies in your mix that need to be attenuated.
Note that when Send mode is active, auto gain compensation has no effect.
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3.5. Processing modes
The GQ-7 offers five processing modes, Stereo, Mid, Side, Mid-Solo and Side-Solo. The default
mode is Stereo, which equalizes one or two channels of audio according to the current parameter
settings. Choosing Mid processes just the center signal, leaving the difference between the left
and right channels untouched. Choosing Side processes only the difference between both
channels, but not the center. Using Mid-Solo and Side-Solo, you can solo either the Mid or Side
channel. This way, the unprocessed channel is no longer audible.
To equalize the Mid and Side channels with separate EQ settings, simply put two GQ-7 instances
in series, then set them to Mid and Side modes, respectively.
3.6. Spectral analysis
By default, the GQ-7 performs a spectral analysis of the incoming signal in real time. Note that
while the horizontal axis showing the frequencies from 25 Hz to 25 kHz is identical for both the
EQ curve and the spectral image, the vertical range is different. The spectral analysis always uses
a range between 0 dB and -90 dB, regardless of the current zoom setting. This is necessary
to be able to see enough of the signal spectrum.
If desired, Spectral Analysis can be turned off on the back panel. This can be useful to save some
processor time when using many instances of the GQ-7 simultaneously.
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3.7. Volume Knob
The volume knob adjusts the output level of the GQ-7. By default it is set to 0 dB, neither boosting
nor attenuating the output signal. The range of the output volume knob is ±15 dB.
3.8. Patch Selector
Use the patch selector to browse factory presets or save your own presets.
Note that while EQ'ing is often situational, but you may find some presets inspiring or work just
right for the task at hand.
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4. CV Modulations
The gain, frequency and Q of all five EQ bands can be modulated via the CV inputs on the back
panel. Furthermore, the frequency of the low- and high shelf filters can be modulated.
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5. Automation and Remote Control
All parameters in the GQ-7 can be remote-controlled and accessed within Reason's Combinator.
5.1. MIDI Map
Parameter CC#
Band 1 Active 12
Band 2 Active 13
Band 3 Active 14
Band 4 Active 15
Band 5 Active 16
Band 1 Gain 22
Band 2 Gain 23
Band 3 Gain 24
Band 4 Gain 25
Band 5 Gain 26
Band 1 Freq 39
Band 2 Freq 40
Band 3 Freq 41
Band 4 Freq 42
Band 5 Freq 43
Band 1 Q 49
Band 2 Q 50
Band 3 Q 51
Band 4 Q 52
Parameter CC#
Band 1 Type
Band 2 Type 71
Band 3 Type 72
Band 4 Type 73
Band 5 Type 74
Low Cut Filter Active 59
Low Cut Filter Freq 60
Low Cut Filter Reso 76
Low Cut Filter Slope 65
High Cut Filter Active 61
High Cut Filter Reso 77
High Cut Filter Freq 62
High Cut Filter Slope 66
Automatic Gain
Compensation
Phase Inversion 68
Send Mode 69
Output Volume 63
EQ Mode 75
70
67
Band 5 Q 53
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5.2. Remote Map
Synapse Audio GQ-7
Band 1 Active 0 1 Toggle Value Output
Band 2 Active 0 1 Toggle Value Output
Band 3 Active 0 1 Toggle Value Output
Band 4 Active 0 1 Toggle Value Output
Band 5 Active 0 1 Toggle Value Output
Band 1 Gain -15 15 Value Value Output
Band 2 Gain -15 15 Value Value Output
Band 3 Gain -15 15 Value Value Output
Band 4 Gain -15 15 Value Value Output
Band 5 Gain -15 15 Value Value Output
Band 1 Freq 25 25600 Value Value Output
Band 2 Freq 25 25600 Value Value Output
Band 3 Freq 25 25600 Value Value Output
Band 4 Freq 25 25600 Value Value Output
Band 5 Freq 25 25600 Value Value Output
Band 1 Q
Band 2 Q 0,2 20,0 Value Value Output
Band 3 Q 0,2 20,0 Value Value Output
Band 4 Q 0,2 20,0 Value Value Output
Band 5 Q 0,2 20,0 Value Value Output
0,2
20,0 Value Value Output
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Band 1 Type 0 2 Value Value Output
Band 2 Type 0 2 Value Value Output
Band 3 Type 0 2 Value Value Output
Band 4 Type 0 2 Value Value Output
Band 5 Type 0 2 Value Value Output
Low Cut Filter Active 0 1 Toggle Value Output
Low Cut Filter Freq 25 25600 Value Value Output
Low Cut Filter Reso 0 100 Value Value Output
Low Cut Filter Slope 0 3 Value Value Output
High Cut Filter Active 0 1 Toggle Value Output
High Cut Filter Freq 25 25600 Value Value Output
High Cut Filter Reso 0 100 Value Value Output
High Cut Filter Slope 0 3 Value Value Output
Automatic Gain Compensation 0 1 Toggle Value Output
Phase Inversion 0 1 Toggle Value Output
Send Mode 0 1 Toggle Value Output
Output Volume -15 15 Value Value Output
EQ Mode 0 4 Value Value Output
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