Source Audio Aftershock Bass Distortion User manual

SA246 Aftershock Bass Distortion User’s Guide 1
Aftershock Bass Distortion User’s Guide
Welcome
Thank you for purchasing the Aftershock Bass Distortion. This powerful stereo effects pedal features
a collection of meticulously crafted Distortion sounds ranging from subtly driven sustain to highly
saturated distortion to thick fuzz and beyond. With a simple control set, the Aftershock can work in a
wide variety of musical settings, and the powerful MIDI and Neuro control options under the hood
provide access to a vast array of additional tonal possibilities.
The Aftershock is housed in a durable, lightweight aluminum housing, packing rack mount power and
flexibility into a compact, easy-to-use stompbox.
The USB and Neuro ports transform the Aftershock from a simple distortion pedal into a powerful
multi-effects unit. Using the free Neuro App (iOS / Android), a wide range of additional control
parameters and effect types (including a large collection of overdrive, fuzz, and distortion sounds)
are accessible. When used together with the Neuro Hub, the Aftershock is fully MIDI-controllable and
128 multi-pedal presets, or “scenes,” can be saved for instant recall on the stage or in the studio. The
Aftershock can also connect directly to a passive expression pedal for expressive control of any
parameter.
The Quick Start guide will help you with the basics. For more in-depth information about the
Aftershock Bass Distortion, move on to the following sections, starting with Connections.

SA246 Aftershock Bass Distortion User’s Guide 2
Enjoy!
-The Source Audio Team
Overview
Diverse Distortion Sounds –Choose from traditional Distortion tones such as Tube, Heavy, and Fuzz,
or delve deeper into unique sounds cooked up in the Source Audio lab.
Compact Design –The durable, anodized aluminum housing has a slim profile, a small footprint, and
sturdy hardware that will withstand the rigors of the road.
Universal BypassTM –True bypass or buffered bypass? The choice is yours. The Aftershock features
high-quality signal relays for true bypass and transparent buffers for analog bypass.
Stacking –Stack two independent distortion circuits in series (or in parallel), all within the same box!
Dual 4-Band EQ + Low Cut –Two independent parametric EQs are included in the Aftershock,
allowing for fine tone control. An optional low cut filter tightens up the low end for bass players.
Flexible Routing –The Aftershock is equally at home in a mono rig or a stereo rig. A variety of routing
modes such as True Stereo, Cascade, Parallel, Dry Sidechain and External Loop allow the Aftershock
to harness the true power of stereo signal chains. Or just use it in Mono mode!
Preset Saving –Save your favorite sound by pressing and holding the footswitch. No need to
remember knob positions in the middle of a show.
Neuro Technology –The Neuro App opens up new possibilities for the Aftershock, including
completely new effect types, additional control parameters, and access to the Neuro Community,
including free presets from artists and other users. The Neuro Hub can store up to 128 presets for
the Aftershock, easily recalled with a MIDI controller. You can also download any effects for the L.A.
Lady Overdrive and Aftershock Bass Distortion and use them on the Aftershock Bass Distortion.
Deep Control Set –Beyond the four knobs on the face of the Aftershock are many additional
parameters. The Neuro App provides access to the inner workings of the Distortion effect for
advanced users who want to create a unique signature sound.
Noise Gate –The built-in adjustable noise gate helps remove unwanted noise.
Clean Path –The clean signal can be mixed in with the distortion as desired, perfect for bass players
who want to hold down the rhythm section with a clean low end.
MIDI Control –All of the Aftershock’s parameters can be accessed and controlled using MIDI via the
Neuro Hub or USB. Class compliant USB-MIDI allows the Aftershock to work as a plug-and-play device
with recording software running on Mac and Windows, and the MIDI Learn feature makes control
mapping simple.

SA246 Aftershock Bass Distortion User’s Guide 3
Quick Start
Power
To power the unit, connect the included 9V DC power supply to the jack labeled DC 9V on the back
panel.
Warning: Using a non-Source Audio supply, especially an unregulated supply, could damage the unit.
Please be very cautious when using 3rd-party power supplies.
Guitar/Audio Connections
Using standard ¼” mono cables, connect your guitar, bass, or other instrument to the INPUT 1 jack
and your amp (or the next audio device in the signal chain) to the OUTPUT 1 jack.
When the power and audio connections have been made, the Aftershock is ready to play.
Brief Knob, Footswitch, and Button Descriptions
Drive Knob: Controls the amount of gain into the distortion circuit, which sets the amount of
distortion and sustain.
Level Knob: Controls the overall output level.
Clean Knob: Controls the amount of clean signal in the output.
Tone Knob: Controls the tone of the distortion.
Effect Switch: Selects between the three basic Distortion effect types –Tube, Heavy, and Fuzz.
Footswitch: Enables or bypasses the Distortion effect. The ON/OFF LED will be lit green when the
Distortion effect is engaged.

SA246 Aftershock Bass Distortion User’s Guide 4
Contents
Welcome.................................................................................................................................................. 1
Overview.................................................................................................................................................. 2
Quick Start ............................................................................................................................................... 3
Connections ............................................................................................................................................. 5
Basic Distortion Operation....................................................................................................................... 8
Effect Types.............................................................................................................................................. 9
Controls.................................................................................................................................................. 10
Preset Storage and Recall ......................................................................................................................11
Universal Bypass TM ................................................................................................................................ 12
Stacking and Parallel Processing “Inside the Box”................................................................................. 12
Stereo Routing ....................................................................................................................................... 13
Parametric EQ........................................................................................................................................16
Low Cut Filter......................................................................................................................................... 17
LoRetain ................................................................................................................................................. 18
Voice Control .........................................................................................................................................18
Noise Gate ............................................................................................................................................. 18
External Control..................................................................................................................................... 19
Neuro App.............................................................................................................................................. 22
Specifications......................................................................................................................................... 32
Troubleshooting..................................................................................................................................... 32
Frequently Asked Questions.................................................................................................................. 33
Rubber Feet ........................................................................................................................................... 35
Waste Disposal Notes ............................................................................................................................ 35
Warranty................................................................................................................................................ 35
Version History ......................................................................................................................................37

SA246 Aftershock Bass Distortion User’s Guide 5
Connections
Input Side Connections
Input 1
This is the primary input for guitar, bass, or other instruments. It can also accept line-level inputs.
Connect it to your instrument or other audio source using a mono (TS) ¼” cable.
Input 2
Input 2 can act either as an audio input or as the data connection for the Neuro App, or both at the
same time.
Input 2 as an Audio Input
The tip contact on Input 2 acts as a secondary input for guitar, bass, or other instruments. It is only
active when the Aftershock is configured with a signal routing that uses stereo inputs. Connect it to
your instrument (or the previous effect in the signal chain) using a mono (TS) ¼” cable. By default,
the Aftershock will auto-detect the routing mode. Other routing options are available using the
Neuro App. For more information about stereo routing, refer to the Stereo Routing section.
Input 2 as a Neuro App Data Input
The ring contact on Input 2 acts as a data connection for the Neuro App. Connect it to your mobile
device using a stereo (TRS) ¼” cable. It can also accept daisy-chained Neuro data from another
Neuro-compatible pedal in the chain, provided that a TRS cable is used. The audio signal (if
applicable) will be on the tip contact of the plug, and the Neuro App data will be on the ring contact.
Input 2 only accepts data from the Neuro App. Data from the Neuro Hub comes from the Control
Input port.

SA246 Aftershock Bass Distortion User’s Guide 6
Output Side Connections
Output 1
This is the primary output. Connect it to your amplifier, recording interface, or the next device in
your effects signal chain using a mono (TS) ¼” cable.
Output 2
Output 2 can act either as an audio output or as the daisy-chain data connection for the Neuro App,
or both.
Output 2 as an Audio Output
The tip contact on Output 2 acts as the secondary audio output. It carries an audio signal when the
Aftershock is configured with a signal routing that uses stereo outputs. Connect it to your amplifier,
recording interface, or the next device in your effects signal chain using a mono (TS) ¼” cable.
Output 2 as a Neuro App Data Daisy-Chain Output
The ring contact on Output 2 acts as a data connection for the Neuro App, passing data from the
Aftershock to the next Source Audio effect in your signal chain. You can daisy-chain the Neuro App
data regardless of whether Output 2 is configured to output audio or not. Connect Output 2 to the
next device’s Neuro App Data input (usually Input 2) using a stereo (TRS) ¼” cable. The audio signal (if
applicable) will be on the tip contact of the plug, and the Neuro App data will be on the ring contact.

SA246 Aftershock Bass Distortion User’s Guide 7
Power and Control Connections
DC 9V (Power)
Connect to the included 9 Volt DC power supply. The power supply must be regulated at 9 Volts
(direct current), able to source at least 180 mA (milliamps) of current, and the plug should have a tip-
negative, sleeve-positive polarity (the center tip is ground and the sleeve is power).
USB
Connect to your computer (Mac or Windows) to the Aftershock’s USB port (denoted by the
icon) using a standard mini USB cable. The Aftershock is a class compliant USB device, meaning that it
should be recognized by Mac and Windows computers automatically. For more information about
the Aftershock’s USB capabilities, refer to the USB section of the User’s Guide.
Control Input
The 3.5 mm Control Input port connects to external control devices such as the Dual Expression
Pedal, Reflex Universal Expression Pedal, Neuro Hub, and Hot Hand Motion Controller. For more
information, refer to the Expression Pedal Input, Hot Hand Input, and Neuro Hub sections of the
User’s Guide.

SA246 Aftershock Bass Distortion User’s Guide 8
Basic Distortion Operation
Distortion is a type of effect that works by distorting the input signal. Distortion can occur in a variety
of ways and results in a wide variety of outputs. This table shows a simple representation of what
some different types of distortion look like.
Clean signal: With no distortion, the guitar
signal passes through the circuit unaffected. In
this example, a pure sine tone is used as a test
signal.
Tube/transistor saturation (soft clipping):
Tube and transistor amplifiers enter a
saturation state when overdriven and start to
distort the shape of the signal. This involves
some soft clipping at the peaks and valleys of
the signal, and may be symmetrical or
asymmetrical in shape.
Asymmetrical:
Symmetrical:
Diode clipping (hard clipping): Diodes can
clamp or limit the signal to a maximum level.
Symmetrical hard clipping: The signal clips
equally on the top and bottom.
Asymmetrical hard clipping: The signal clips at
different levels on the top and bottom.
Overshoot: Depending on the characteristics
of diodes and transistors in the circuit, the
signal may exceed its normal clipping point
before settling, which is known as overshoot.

SA246 Aftershock Bass Distortion User’s Guide 9
Extreme overshoot: The overshoot
phenomenon can be taken to its extreme for
fuzz and metal sounds.
Octave: A rectifier can be used to double the
frequency of the signal, creating an octave fuzz
effect with a unique tonal character.
The various drive circuits in the Aftershock Bass Distortion utilize a combination of these different
approaches to create tones inspired by the classics, as well as new groundbreaking tones that bring
their own unique flavors.
Effect Types
The Aftershock includes three basic distortion types, with more effects available in the Neuro mobile
app.
Tube
The Tube circuit offers an overdriven amp distortion sound with a smooth texture. Good for adding a
little extra grind for an “always on” tone.
Heavy
The Heavy circuit creates a hybrid sound somewhere between the big-bottom Electro-Harmonix Big
Muff Pi® and gritty Way Huge Swollen Pickle®. Great for power trio grinding bass low end.
Fuzz
A wild, digital sounding fuzz held back by a sensitive noise gate. Similar to a ZVex Woolly Mammoth®.
Experiment with different levels of additional noise gate to find some of the most unique sounds
hidden in the Aftershock.
Additional Effect Types
Additional effect types can be loaded into the Aftershock using the Neuro App on your mobile device
(iOS / Android) or the built-in USB port (Mac / Windows).
The Aftershock Bass Distortion is compatible with Source Audio’s Overdrive and Fuzz effects, so it is
possible to load Overdrive, Distortion, and Fuzz effects on the Aftershock at the same time.

SA246 Aftershock Bass Distortion User’s Guide 10
Controls
Knobs
Drive Knob
The DRIVE KNOB adjusts the amount of gain applied to the signal. Dial down the drive for a cleaner,
more articulate tone or crank it up for over-the-top doses of distortion.
Level Knob
Adjusts the output level of the effect. This is useful for setting the level of the distortion effect
compared to the bypassed signal. Note that because the distortion effect compresses the signal in
the clipping/saturation stage, the dynamic range of the distorted signal will be less than the dry
signal, and the LEVEL KNOB can be used to compensate for the loss of level that results from this
compression.
Clean Knob
The Clean Knob adjusts the amount of dry signal on the output. This is very useful for keeping a solid
low end with high amounts of drive.
Drive Knob
Effect Switch
Clean Knob
Level Knob
Tone Knob
Engage/Bypass
LED
Engage/Bypass
Footswitch
Control LED Control Input Button

SA246 Aftershock Bass Distortion User’s Guide 11
Tone Knob
The Tone Knob adjusts the overall tone of the distortion. Turn clockwise for brighter sounds and
counter-clockwise for darker, warmer sounds.
Effect Switch
Selects between the three basic Distortion effect types –Tube, Heavy, or Fuzz. These effects are
described in further detail in the Effect Types section.
LEDs
Engage / Bypass LED
The ENGAGE /BYPASS LED above the footswitch indicates if the Distortion effect is active (lit green) or
bypassed (not lit).
When the user preset mode is enabled, the LED will turn red. See the Preset Storage and Recall
section for more information about user presets.
External Control LED
The small LED located between the Depth and Speed knobs is the EXTERNAL CONTROL LED. When lit, it
indicates that external control mode (expression, hot hand, or MIDI) is active. For more information,
see the External Control section.
Footswitch
Enables or bypasses the Distortion effect.
Control Input Button
This small button is used when configuring external control. See the External Control section for
more details.
Preset Storage and Recall
The Aftershock features a user preset that can be easily saved and recalled using the footswitch.
When a preset is recalled, all of the parameters instantly jump to their saved value, regardless of the
position of the knobs. This allows you to save your favorite sound without having to worry about the
knob positions.
Saving Your First Preset
Bypass the Aftershock by clicking the ON/OFF FOOTSWITCH once. The ENGAGE/BYPASS LED should
be dark at this time.
Press and hold the ON/OFF FOOTSWITCH for 5 seconds and wait for the ENGAGE/BYPASS LED to turn
red. You are now in preset mode.
Set up the effect how you want it to sound, including the EFFECT SWITCH, LEVEL KNOB, DRIVE KNOB,
CLEAN KNOB AND TONE KNOB. Once you have made a change, the ENGAGE/BYPASS LED will begin to
blink.
To save your preset, hold the footswitch until the ENGAGE/BYPASS LED blinks rapidly 3 times.
Now you can engage and bypass the Aftershock using the ON/OFF FOOTSWITCH, and each time
you engage the effect, your saved preset will be recalled.

SA246 Aftershock Bass Distortion User’s Guide 12
Editing a Preset
Activate your preset (the ENGAGE/BYPASS LED will be solid red).
Change any parameter you wish (EFFECT SWITCH, LEVEL KNOB, DRIVE KNOB, CLEAN KNOB AND TONE
KNOB). Once you have made a change, the ENGAGE/BYPASS LED will begin to blink.
When you are ready to save, press and hold the ON/OFF FOOTSWITCH for a few seconds. The
ENGAGE/BYPASS LED will blink three times to show that the preset was saved.
Exiting Preset Mode
When Preset Mode is active, bypass the effect using the ON/OFF FOOTSWITCH. The ENGAGE/BYPASS
LED should be dark at this time.
Press and hold the ON/OFF FOOTSWITCH for 5 seconds and wait for the ENGAGE/BYPASS LED to turn
green. You have now exited Preset Mode.
Universal Bypass TM
Most effect pedals offer either true bypass or buffered bypass. The Aftershock contains two separate
circuits for bypass mode, allowing you to choose the method you prefer. The true bypass path uses
signal relays, which are electromechanical switches. This provides an ultra-low resistance path from
the input jacks to the output jacks, which is effectively the same as a wire. The buffered bypass path
uses extremely low noise buffers, which provide a very low output impedance and are effective for
driving long cables or long chains of effects following the Aftershock’s audio output.
Out of the box, the Aftershock operates in true bypass mode. In order to switch to buffered bypass
mode, edit the Aftershock’s global settings using the Neuro App.
We recommend you choose between the active analog bypass (a.k.a. buffered bypass) and relay-
based true bypass based on what is needed in your signal chain. Ideally, the first pedal in a signal
chain is a buffered input followed by true bypass in the rest of the signal chain.
Both bypass methods have pros and cons associated with them. Buffered bypass provides consistent
input impedance so that if the source is susceptible to variations in input impedance (similar to a
guitar pickup), there won’t be a noticeable change in tone. True bypass has the benefit of providing a
dedicated hardwired bypass signal path. The Aftershock features small-signal relays for true bypass
switching that offer reduced pops and clicks compared to the traditional true bypass switching
method using a mechanical switch.
Stacking and Parallel Processing “Inside the Box”
The Aftershock works great as a simple mono Distortion effect, but it has the power to do much
more. Within the Aftershock, two completely independent overdrive, fuzz, or distortion circuits can
be set up to run stacked (in series), in parallel (side-by-side and mixed), or even in true stereo.
Usually, this would require two separate distortion pedals, but the Aftershock can do it all on its own.
Stacking (Series / Cascaded)
Stacking overdrive, fuzz, and distortion pedals is a common method for creating unique textures that
would not be possible with a single pedal. This normally involves putting two pedals in series, one
after the other, to create multiple gain stages. Typically, this requires two separate distortion pedals,

SA246 Aftershock Bass Distortion User’s Guide 13
but the Aftershock can do it all internally. Each of the two drive stages, called A and B, can be
configured independently using any overdrive, fuzz, or distortion circuit, with its own independent
settings (drive, level, EQ, noise gate). This routing option is designated as MONO IN/OUT WITH
CASCADING CHANNELS in the Neuro App.
Parallel Processing
Another common way to create new and interesting distortion sounds is to split the guitar signal, run
it to two independent pedals in parallel, and then combine (mix) the results. Often, one path will
have a relatively low gain and the other will have high gain. This approach can combine high gain
power and sustain with low gain clarity, definition, and articulation. The right balance can make
parallel processing very effective. Usually this approach requires a lot of hardware: two distortion
pedals, a splitter, and a mixer. The Aftershock, however, can do it all internally. Each circuit has its
own clean and drive level controls, which allow for very fine balancing between the two sounds.
There are two parallel processing routing options available in the Neuro App: MONO IN STEREO PROCESS
MONO OUT and MONO IN STEREO PROCESS STEREO OUT.
Series / Parallel Hybrid
By selecting the MONO IN/OUT WITH CASCADING CHANNELS routing option and bringing up the clean mix
level on channel B, it’s possible to create a series/parallel hybrid sound, as shown in the image
below:
Stereo Routing
The Aftershock works great as a mono Distortion effect, but its stereo inputs and outputs also make
it a true stereo effect as well as a flexible signal router. It can act as a stereo splitter, merger, or true
stereo effect, and it can also be set up in a number of other unique signal routing modes. By default,
Stacking (Cascade)
A
1 1
B
EQ
A
EQ
BFrom Guitar
To Amp
Parallel
11
A
EQ
A
B
EQ
BFrom Guitar
To Amp
Series + Parallel Hybrid
A
11
B
EQ
A
EQ
BFrom Guitar
To Amp

SA246 Aftershock Bass Distortion User’s Guide 14
the Aftershock works in true stereo mode (INPUT 1 goes to OUTPUT 1, and INPUT 2 goes to OUTPUT 2).
To configure a different stereo routing mode, use the Neuro App.
A few different routing options are displayed below. The right side of each diagram shows inputs 1
and 2, the left side shows outputs 1 and 2, and the distortion and EQ circuits (labeled A and B) are in
the center.
Mono (Default –Auto Select): INPUT 1 goes to distortion circuit A and out to OUTPUT 1.
True Stereo (Stereo In, Stereo Out): INPUT 1 goes to distortion circuit A and out to OUTPUT 1. INPUT 2 goes
to distortion circuit B and out to OUTPUT 2.
Parallel (Mono In, Stereo Process, Stereo Out): INPUT 1 is split into two identical signals. One signal goes
to distortion circuit A and out to OUTPUT 1. The other signal goes to distortion circuit B and out to OUTPUT
2. This essentially turns the Aftershock into a splitter that takes a single input and feeds two amps (or a
stereo signal chain).
Stereo In, Mono Out: INPUT 1 goes to distortion circuit A. INPUT 2 goes to distortion circuit B. The outputs
of circuits A and B are mixed and sent to OUTPUT 1. This is useful for mixing a stereo source down to a
mono output.
A1
EQ
A
1
Mono
From Guitar
To Amp
True Stereo
A
EQ
A
B
EQ
B
1
2
1
2
From Guitar
To Amp
Parallel (Stereo)
1
A
EQ
A
B
EQ
B
1
2From Guitar
To Amp (R)
To Amp (L)

SA246 Aftershock Bass Distortion User’s Guide 15
Mono, Dry Thru: INPUT 1 goes to distortion circuit A and out to OUTPUT 1. A copy of the input is also sent
to OUTPUT 2. This is useful especially for bass guitars, where having a dry output is useful in maintaining a
solid low end (this can also be achieved using the Aftershock’s mix control or LoRetain feature, which
are accessible via the Neuro app and MIDI).
External Loop Pre-Effect: The external loop options allow an external effect (whether a Source Audio
product or a third-party product) to be connected to the Aftershock’s INPUT 2 and OUTPUT 2. When the
Aftershock is bypassed, the external effect will be out of the circuit. When the Aftershock is enabled, the
external effect will be put in series with the Aftershock’s distortion circuit. OUTPUT 2 should connect to
the external effect’s input, and the external effect’s output should connect to INPUT 2.
In Pre-Effect mode, the guitar signal will go to the external effect first, and then the Aftershock’s
distortion circuit second.
In Post-Effect mode, the guitar signal will go to the Aftershock’s distortion circuit first, and then to the
external effect second.
Stereo In, Mono Out
1A
EQ
A
B
EQ
B
1
2
To Amp
Input (L)
Input (R)
Mono, Dry Thru
2
A1
EQ
A
1From Guitar
To Amp (R)
To Amp (L)
External Loop Pre-Effect
X
1
2
1
2
A
EQ
A

SA246 Aftershock Bass Distortion User’s Guide 16
Automatic Routing Mode Selection
By default, the routing mode is automatically chosen. The cables connected to the inputs and
outputs are detected and the mode is set according to the below table:
Input(s)
Output(s)
Routing Mode
1 only
1 only
Mono Input, Mono Output
1 and 2
1 only
Stereo Input, Stereo Parallel Processing, Sum to Mono Output
1 only
1 and 2
Mono Input, Stereo Parallel Processing, Stereo Output
1 and 2
1 and 2
Stereo Input, Independent Stereo Processing, Stereo Output
Check the Neuro App for more details on routing options.
Parametric EQ
The Aftershock features two built-in 4 band parametric EQs that can be configured using the Neuro
App. Different EQ settings can be saved for each of the three effect types, as well as for the user
preset. The EQs consist of four independently configurable bands:
Bass (Band 1): Low Shelf
Mid A (Band 2): Peaking (a.k.a. Bell / Band)
Mid B (Band 3): Peaking (a.k.a. Bell / Band)
Treble (Band 4): High Shelf
Each band has configurable frequency, boost/cut, and Q (bandwidth).
A simple example of these four bands in action is shown in the graph below. In this example, Band 1
is a low shelf filter at 100 Hz with a 6 dB cut, Band 2 is a peaking filter at 620 Hz with a 3 dB cut and
relatively high Q, Band 3 is a peaking filter at 3 kHz with a 1.5 dB boost and relatively low Q, and Band
4 is a high shelf filter at 10 kHz with a 2.5 dB cut.
External Loop Post-Effect
X
1
2
1
2
A
EQ
A

SA246 Aftershock Bass Distortion User’s Guide 17
By default, Band 1 is a shelf when it is boosted (gain > 0 dB) and a high pass when it is cut (gain < 0
dB). By default, Band 4 is a shelf when it is boosted (gain > 0 dB) and a low pass when it is cut (gain <
0 dB). Using the Neuro App, Bands 1 and 4 can optionally be configured as a shelves when cutting
(gain < 0 dB), with optional values for slope and rolloff.
The left channel and right channel can each have unique boost/cut values for each of the 4 bands.
However, the filter types and cutoff frequencies (or center frequencies) must be the same for both
channels.
The physical TONE KNOB directly controls the boost or cut of the parametric EQ’s bass and treble
bands.
Low Cut Filter
The Aftershock also includes two low cut filters (a.k.a. high pass filter) with an adjustable frequency.
This filter is very useful for cutting out low frequencies that do not contribute to the sound of the
instrument, as well as subsonic frequencies which cannot be heard at all. Bass players often use low
cut filters set very low (around 10 Hz to 30 Hz) to reduce speaker excursion and improve the clarity of
the bass. Guitarists often use low cut filters set somewhat higher (around 80 Hz) in order to give the
bass player additional room in the low end of the mix.
50 100 200 300 500 1.0k 2.0k 3.0k 5.0k 10.0k 20.0k
-6
0
+6
1234
Parametric Equalizer

SA246 Aftershock Bass Distortion User’s Guide 18
The Parametric EQ and the Low Cut filter are configurable using the Neuro App. By default, the
parametric EQ is disabled (flat), and the Low Cut filter is set to 10 Hz.
LoRetain
LoRetain is a technique used by Source Audio to maintain a solid low end even with high amounts of
distortion. This is particularly useful for bass players or extended-scale guitar players (7-string and 8-
string guitars) that need to maintain a strong fundamental while keeping high drive on the upper
frequencies. LoRetain is available as a control independent of the parametric EQ and low cut filter.
Voice Control
Each overdrive/fuzz/distortion circuit features a VOICE control that is a gradual timbre adjustment
affecting the overall character of the sound. It generally affects the midrange in subtle ways, so a
high VOICE setting will generally provide a midrange boost, whereas a low VOICE setting will provide a
midrange cut. Many different sounds are available using the VOICE control, which can be controlled
via the Neuro App.
Noise Gate
Overdrive, fuzz, and distortion effects introduce a lot of gain into the signal chain, and this gain
amplifies not just the guitar signal, but also any noise present in the system. As a result, overdrive,
fuzz and distortion effects tend to increase the amount of noise in the signal chain, especially when
the guitar is silent or playing at very low levels. In order to correct this problem, guitarists often use
noise gates prior to the distortion stages in their signal chains. The Aftershock includes a built-in
noise gate to help reduce noise and preserve the guitar signal. The noise gate consists of a traditional
gain reduction circuit as well as a filter gate, which works by attenuating high noisy frequencies when
50 100 200 300 500 1.0k 2.0k 3.0k 5.0k 10.0k 20.0k
-6
0
+6
Configurable Low Cut Filter

SA246 Aftershock Bass Distortion User’s Guide 19
necessary. By default, the noise gate is not active. The volume gate and filter gate can independently
be enabled and configured using the Neuro App. The gate will automatically be linked in stereo
modes or independently configured in stacking and parallel modes.
External Control
The CONTROL INPUT port opens up a wide array of external control options, allowing for direct control
over many of the Aftershock’s built-in parameters. It can be used as an expression input or as a data
port for the Neuro Hub.
Expression Control
The Aftershock’s effects parameters can be controlled directly by an expression pedal or Hot Hand
connected to the CONTROL INPUT port.
Expression Pedal Input
The Dual Expression Pedal or Reflex Universal Expression Pedal, both from Source Audio, can be
directly connected to the CONTROL INPUT using a 3.5 mm, TRRS cable.
In the case of an expression pedal with a TRRS plug, like Source Audio’s expression pedals, the tip
connection is power, the first ring is the X axis expression signal, the second ring is the Y axis
expression signal, and the sleeve connection is ground.
Third party passive expression pedals can be used as well, as long as they have a TRS (Tip Ring Sleeve)
plug with power on the tip, expression (the wiper of the potentiometer) on the ring, and ground on
the sleeve, as seen in the diagram below.
Expression pedals with TS (Tip Sleeve) plugs will not work correctly with the Aftershock.
Ground Power
Y Exp X Exp
Ground Power
Expression

SA246 Aftershock Bass Distortion User’s Guide 20
The resistance of the expression pedal does not matter. The Aftershock will automatically adjust
itself to the range of the expression pedal when it is configured.
Most expression pedals use a ¼” plug, but the Aftershock’s CONTROL PORT is 3.5 mm. To make the
connection, a simple TRS plug converter (1/4” to 3.5 mm) can be used.
Note that although the CONTROL INPUT expects a 4-contact TRRS plug, most 3rd party expression pedals
use a 3-contact TRS plug. This is OK –using a simple 3-contact TRS plug converter, the expression
pedal’s output will be connected to the Aftershock’s CONTROL INPUT and the extra contact is ignored.
Configuring the Expression Pedal
It is easier than ever to set up expression control using the Aftershock’s new calibration and mapping
method. When the expression pedal is connected to the Aftershock, follow these simple steps to
calibrate it and map it to control different effect parameters.
1. Press the CONTROL INPUT button to turn on Control Input mode. The CONTROL LED should be lit
green.
2. Press and hold the CONTROL INPUT button until the CONTROL LED begins to blink slowly
(approximately one blink per second).
3. Move the expression pedal over the range of motion you would like to use to control the
Aftershock. If you would like to use the expression pedal’s full range of motion, then make
sure to move the pedal all the way from its minimum position to its maximum position.
Note that you can create “dead zones,” if desired, by only moving the expression pedal over
a limited region of its full range of motion.
4. After setting the expression pedal range, click the Aftershock’s footswitch once. The
calibration is now complete, and the CONTROL LED will blink faster (about 2 blinks per
second). Now, it is time to map the expression pedal to the effect parameters.
5. Move the knob(s) you wish to control with the expression pedal to the minimum desired
position, then click the Aftershock’s footswitch. The CONTROL LED will now blink even faster
(about 4 blinks per second). Note that you may control one or more knobs with the
expression pedal, up to four total knobs.
6. Move the knob(s) you wish to control with the expression pedal to their maximum desired
position, then click the footswitch. The CONTROL LED will now be lit solid green. Note that
you may control one or more knobs with the expression pedal, up to four total knobs.
7. After setting the minimum and maximum knob positions, the parameter mapping is
complete.
Note: The parameter range can be inverted by swapping the minimum and maximum position of the
knobs during configuration.
External Switch used as Expression Input (Expression “Toggle”)
An external switch can also work as a sort of expression pedal that only has two positions: on and off.
The external switch can be either momentary or latching.
To use this mode, connect an external switch to CONTROL INPUT. The following plug configuration is
required: