C4 Synth User Guide Welcome Thank you for purchasing the C4 Synth. This advanced piece of gear offers all the sound construction tools of a classic Eurorack modular synthesizer and packages them in a compact and easy-to-use effects pedal for guitar and bass. It is essentially a Eurorack modular synth in a box with unprecedented tracking abilities, lightning-fast response, and countless sound options. Out of the box the C4 offers six unique and dynamic synthesizer effects.
Overview Six Preset Positions: Use the C4’s three-position toggle switch and two preset banks to save six easily accessible presets. Growing Library of Published Presets: For quick access to a world of great tones, try sampling sounds from a vast collection of published presets created by the Source Audio team and the ever-growing C4 Neuro Community.
USB host. The USB port also offers connectivity to the Neuro Desktop Editor providing access to deep editing possibilities and pedal firmware updates. External Expression and Tap Tempo Control — Use the Control Input jack with the Source Audio Dual Expression Pedal (expression control to multiple parameters) or Tap Switch (adjust LFO rates on the fly).
The C4 Synth: How Does It Work? Before diving fully into the C4 Synth and its Neuro Editor, it is important to understand the basic internal layout and signal path. Below is a simple block diagram that illustrates the C4’s Signal Path and Resource Blocks: Step 1. The Voices: First in line are the C4’s Voices (there are four of them, hence the name “C4”). Assigned each activated Voice to its own Sound Source (Sine, Square, or Saw Oscillator / Monophonic Pitch / Polyphonic Pitch/ Dry Signal).
Quick Start Power To power the unit, connect the included 9V DC power supply to the jack labeled DC 9V on the back panel. When running a 3rd party power supply, the C4 Synth requires an isolated 9V DC power source with a minimum of 165mA and a center-negative plug. 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.
made then automatically switch back to the primary parameters five seconds after the last knob adjustment. INPUT/SENS Knob: A dual function knob that adjusts the level of INPUT signal going to the processor, and also the SENSITIVITY of the envelope filter. To access the • • INPUT (the Primary (Default) Parameter): Adjusts the volume level of the input signal.
Contents Welcome ................................................................................................................................................ 1 Overview ................................................................................................................................................ 2 The C4 Synth: How Does It Work? .......................................................................................................... 4 Quick Start .......................................
Connections Input Side Connections Input 1 This is the primary input for guitar, bass, or other instruments. It can also accept line-level inputs of up to +6.54 dBV / 8.76 dBu. Connect it to your instrument or other audio source using a mono (TS) ¼” cable. Input 2 Input 2 acts as either a second audio input, the data connection for the Neuro Mobile App, or an input for both audio and Neuro Data simultaneously.
Output Side Connections Output 1 This is the primary mono Output. Connect this Output to your amplifier, recording interface, or the next device in your effects signal chain using a mono (TS) ¼” cable. Output 2 Acts as either an audio output, the daisy-chain data connection for the Neuro App, or both audio and Neuro Data simultaneously. Output 2 as an Audio Output The tip contact on Output 2 acts as the secondary audio output.
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 165 mA (milliamps) of current, and the plug should have a tipnegative, sleeve-positive polarity (the center tip is ground and the sleeve is power). USB Connect your computer (Mac or Windows) to the C4’s USB port (denoted by the icon) using a standard mini USB cable.
Controls Knobs ALT (Alternate) Button The small black button located on the topside of the pedal next to the CONTROL INPUT jack. Pressing the ALT button temporarily puts the pedal into Alternate Control Mode (indicated by the blinking ALT Function LED). Alternate Control Mode switches from the Primary to Secondary function of the INPUT/SENS and MIX/VOL knobs. Also moving the center toggle switch will change the Preset Bank.
turn the INPUT knob down. For traditional passive pickups it will help to turn the INPUT level up. o INPUT CALIBRATION FUNCTION: We have provided a unique Input Calibration Function to assure that you are getting the best possible interaction between your instrument and the C4. The Calibration process is as follows: 1. Turn the INPUT knob all the way down. 2. Continuously pluck your instrument at your average plucking velocity. 3. Slowly turn up the INPUT knob up until the center LED starts flashing red.
blinking top center LED). Alternate Control Mode switches from the Primary to Secondary function of the INPUT/SENS and MIX/VOL knobs. Moving the toggle switch while the pedal is in Alternate Control Mode will switch between the green and red preset banks. LEDs Engage / Bypass LED The Engage / Bypass LED above the footswitch indicates if the effect is active (lit) or bypassed (not lit).
Accessing the Green and Red Preset Banks The C4 can store up to six presets (2 banks of 3 presets) accessible without a MIDI controller or the Neuro Editor. • • Green Preset Bank (Indicated by the green center LED): By default the center toggle switch selects between three presets (Circle, Triangle, Square) stored in the first (green) bank of presets.
WYSIWYG (What You See Is What You Get) Mode In WYSIWYG Mode the C4 functions much like a traditional effects pedal. It is a” What You See Is What You Get” experience, meaning that the current physical positions of the knobs will indicate the settings of the primary knob functions.
External Control The CONTROL INPUT port opens a variety of external control options, allowing for direct control over many of the C4’s parameters. It is an input for the, Source Audio Tap Switch, Source Audio Dual Expression Pedal, or a data port for the Neuro Hub. The Source Audio Tap Switch The Source Audio Tap Switch connects directly to the CONTROL INPUT with a 1/8” TRRS cable. The Tap Switch can be used for a variety of tasks. • Tap Tempo: Manually tap in the rate of the LFO.
Although the CONTROL INPUT port expects a 4-contact TRRS plug, it is still possible to use a 3rd party expression pedal with a 3-contact TRS plug (Note: you should make sure the expression pedal’s TRS configuration is the same as the graphic below). Use a 3-contact 1/4” to 1/8” (3.5mm) TRS plug converter - the expression pedal’s output will be connected to the C4’s X-axis.
Configuring the Hot Hand Use the C4 Synth’s Neuro Sound Editor to assign Hot Hand control to up to three parameters. Hot Hand expression editing is accomplished in the External Control block of the Neuro Sound Editor. For more info on assigning expression control to the C4 go to the External Control section of this manual.
Neuro Mobile App & Neuro Desktop Editor The C4 Synth was designed to be a simple plug-and-play effects pedal. Straight out of the box, the C4 offers six great sounding guitar/bass synth effects, but connecting the C4 to the Neuro Mobile App and Neuro Desktop Editor a vast Library of easy-to-access Presets created by the Source Audio team and the ever-growing community of C4 Synth users. The Neuro Editor also offers a super-powerful Sound Editor for creating, saving, and sharing your own custom Presets.
connection a blue box will appear in the Connections field of the Neuro interface indicating that the C4 is ready for editing. If your C4 Synth is in need of a firmware update, the Firmware Update icon (the arrow icon) will be framed in yellow. Upon clicking the arrow icon, you will be instructed on the updating procedure. (Note: It is important disconnect all other Source Audio pedals and turn off MIDI software during the firmware updating process.
Connections The Connections section is located on the left side of the Neuro Desktop Editor. This field displays all connected One Series pedals. Each connected pedal offers the three options listed below: • Firmware Updates (Arrow Icon): Click to download any recent firmware updates to the connected pedal. If an update is available this icon will be framed in yellow. Upon clicking the icon, the software will provide instructions on how to proceed.
Hardware Options Clicking the gear icon in the C4 Synth’s Connections window opens the Hardware Options menu (see the graphic below). Use the Hardware Options window to choose your pedal’s global hardware settings. The C4 Synth’s Hardware Options include the following: • • • • • • SA249 Preset/WYSIWYG: There are three different Preset Modes available in the C4: Standard (Default), Preset, and WYSIWIY (“What You See Is What You Get”). Use this dropdown menu to select the Preset Mode.
• • • • Default Input: Selects the default configuration of the Input jacks. There are four different options: Auto Detect (Default), Single Input 1, Dual Input 1 & 2, External Loop (PreProcessing). Go to the Routing and Options section for details on all of the routing choices. Quick Bank Switch Using Footswitch (2 Seconds): By default you can only use the footswitch to alternate between Preset Bank 1 (Green LED) and Preset Bank 2 (Red LED) from the disengaged state.
• • • • • • steady rate set by the Speed control in the LFO and Arpeggiator section. Turning the knob all the way to the left provides 100% envelope follower control and turning the knob all the way to the right provides 100% LFO control. Setting the knob anywhere in between creates a mixture of both types of filter modulation. Bass: Boosts or cuts the low frequencies of the wet signal. Treble: Boosts or cuts the high frequencies of the wet signal. Mix: Sets the ratio between the wet and dry signal.
Monophonic Pitch 1 and 2: Routes the dry signal through the Monophonic Pitch shifting module. The Monophonic Pitch Shifter applies pitch-shifting effects to single note lines (a.k.a. “not chords”). Use the Interval pull-down menu to select an interval up or down three octaves. Selecting the Harmony option from the Interval pull-down menu allows for intelligent harmonization – choose the key and scale in the Harmony block. o Saw 1 & 2: A true Saw Wave Oscillator synthesizer Voice.
• • • • • • Tremolo knob: Each Voice’s dedicated Tremolo control sets that Voice’s individual tremolo depth. The rate of all the Voices’ tremolo effects are synced to the tremolo wave shape and Speed knob in the LFO Module located further down the Editor. LFO Dropdown Menu: Selects whether the tremolo effect responds to LFO 1 or 2. Detune Knob and Modulate Button: Use the Detune knob to adjust the Voice’s pitch either up or down.
• • • Drive Knob: Adjusts the amount of distortion. Clean Mix Knob: Adjusts the mix ration of clean to distorted signal. Setting the Clean Mix all the way to left offers a 100% clean mix, all the way to the right is a 100% distorted mix, and 12 o’clock on the knob offers a 50/50 clean/distorted mix. Output Knob: Adjusts the overall level of the output signal coming from the Distortion block. Processor 1 & 2 Filters The Filters play a crucial role in developing the character of your preset.
• • Envelope/LFO Selector Dropdown Menu: Selects whether Envelope/LFO 1 or Envelope/LFO 2 controls the filter modulation. Pitch Tracking Drop Down: Engaging the Pitch Tracking initiates a function where the Filter modulation and Pitch Tracking work in tandem, meaning that the filter will move its starting point in the frequency spectrum based on the note that is being played. There are three different pitch to filter frequency ratios: 1/3 Octave, 2/3 Octave, and 1 Octave.
o o Output 1 + Output 2: Routes all of that Processor’s signals to both the Output 1 & 2 jacks. Output 2 Only: Routes all of that Processor’s signals to the C4’s Output 2 jack. Envelope 1 & 2 The Envelopes control amplitude and filter modulation of the each C4 Voice. Both Envelopes 1 and 2 run independently of each other and each can be assigned a different set of Voices.
LFO 1 & 2 The LFOs (Low Frequency Oscillators) can be set to control the Filter modulation, Sequencer rates, or Tremolo rates (amplitude modulation). • • • • • • • SA249 LFO Wave Shape Selector Dropdown Menu: Choose from 14 different LFO wave shapes. Each wave shape evokes a different character from the Filter and Tremolo modulation. Choose from a range of sounds from a smooth Sine wave modulation to a choppier Square wave modulation.
• • • • • • Tap Tempo Button: Tap this button in time with a drummer or rhythm track to override the Speed knob’s setting and manually set the LFO rate. Please note that if LFO 1 and LFO 2 are set to different beat divisions, both rates will increase or decrease to scale during Tap Tempo adjustments. Beat Division Dropdown Menu: Sets the beat division of LFO 1. Note that the beat division of LFO 2 is a sub-set of LFO 1 and it is set in the LFO Time Ratio Dropdown Menu.
Pitch Detector The C4’s Pitch Detector is an algorithm that detects the pitch of the connected instrument and uses it as a guide to create Pitch Synthesis, Shifting or Harmony effects. In nearly every case the user doesn’t need to worry about the response of the Pitch Detector – that said, we do offer some adjustable parameters that refine the Pitch Detector and further decrease latency and improve pitch accuracy.
• • • Mode Dropdown Menu: Sets the scale or mode of to which the harmonization adheres. Scale and modes include: Ionian (Major), Dorian,Phrygian, Lydian, Mixolydian, Aeolian (Natural Minor), Locrian, Harmonic Minor, Locrian Natural 6, Ionian #5, Dorian #4, Phrygian Natural 3, Lydian #2, Altered bb7, Jazz Minor, Phrygian Natural 6, Lydian #5, Lydian b7, Mixolydian b6, Locrian Natural 2, Altered Scale, Half-Whole, Whole-Half Intervals 1 & 2 Dropdown Menus: Selects the core harmony interval for each Voice.
• • the Control Source dropdown menus to select the type of external controller being used. There are three different options in this menu: o Control Input X: Select this option when using an expression pedal or the X-axis of the Hot Hand 3 Wireless Controller. o Control Input Y: Select this option when using the Y-axis of the Hot Hand 3 Wireless Controller. o Expression (Hub/MIDI): Select this option when using an expression controller connected to the EXP IN or SENSOR IN jacks on the Neuro Hub.
routing option that can’t be set up manually is the an external effects loop that places the external effect in front of the C4’s Voice processor. Choose this option if you wish to create a pre-Voice external effects loop. See the diagram below to get a better understanding of the routing. • Preset Recall State: Selects the Engaged/Disengaged state of the preset when recalled via a MIDI Program Change (PC) message.
the Published Presets of other C4 Synth users. There are two views available in the Presets section click on the icon labeled Device or Cloud (located in the blue square on the top right corner) to open each view respectively. Device Clicking the Device icon on the top-right corner of the Presets section opens the Device interface. This view displays the presets saved to all 128 possible locations on your C4 pedal.
• • the SAVE TO CLOUD button. A box will pop up asking you to name it and provide a description. It will also ask you for YouTube or SoundCloud link (this is optional). The YouTube and SoundCloud links are there for you to embed sound clips of your preset so that others can quickly hear what you’ve created. From there you can either Save it to your private Cloud based storage (available in the My Library tab in the Cloud view) or Save and Publish it for the rest of the C4 community.
Browse, Burn, and Play The Cloud offers access to the vast landscape of C4 preset created by the Source Audio staff and the ever-growing community of C4 users. It’s as easy as “Browse, Burn, and Play.” The graphic above displays the Cloud view of C4 Synth User Presets. To test a Preset, simply click anywhere on the Preset listing, instantly the Preset will upload to your C4 pedal. If you like what you hear go to the top-right corner of that Preset listing and click either the BURN or DOWNLOAD icons.
To save a Preset to your personal Library of Presets, click the Download icon and hit SAVE. The Preset will store instantly to the MY LIBRARY tab. • • • • COMMUNITY Tab: Click the Community tab to view all of the presets created by the entire Neuro community. To test a preset, simply click anywhere on the preset listing and it will instantly upload to your C4 pedal. FACTORY Tab: Contains presets created by the Source Audio team and other synth aficionados.
A standard set of TS and TRS cables work as well (we recommend the flat TS and TRS cables manufactured by Rockboard). The examples below explain how to make your Neuro Daisy-Chain connections in a mono or stereo rig. Mono Audio Path with Neuro Daisy-Chain In the case of a purely mono audio signal path, the Neuro data can be input to the first effect directly from the mobile device and then carried on to the second effect via TRS cable.
MIDI Through the USB Port or Neuro Hub The C4 responds to MIDI Program Change (PC) and Continuous Controller (CC) messages via its mini USB port. The C4 Synth’s USB port is plug-and-play ready for Digital Audio Workstation (DAW) software on Windows and Mac computers. The C4 uses class-compliant drivers, so no special drivers are needed. Just power up the pedal and connect it to the computer using a USB cable.
The C4 Synth and the Neuro Hub Currently the C4 Synth cannot receive MIDI Program Changes (PC) and change presets via the Neuro Hub – PC messages can only come through the C4’s USB port. However, the C4 can receive MIDI CC messages through a Neuro Hub connection. Custom MIDI CC Mapping The C4 Synth has very few default MIDI mapping - MIDI CC messages must be mapped with the Neuro Desktop Editor. Custom MIDI CC mappings are global; they will apply in all situations, regardless of which preset is active.
MIDI Clock The C4 Synth’s LFO will sync to MIDI clock messages (also known as MIDI timing clock or MIDI beat clock). MIDI clock is tempo-dependent and is used to ensure that multiple MIDI-enabled devices stay in synchronization. A common use of MIDI clock with the C4 is when recording along to a click track in a DAW (Digital Audio Workstation) running on a computer. MIDI clock can be sent to the C4 directly over USB-MIDI or the Neuro Hub. MIDI Clock can be enabled within the C4 on a per-preset basis.
• Height (including knobs and footswitch): 5.61 cm (2.21 inches) Weight • 280 grams (0.625 pounds) Power • • 9V DC, minimum 165 mA (maximum 195 mA when connected to a power reliant external controller) Negative tip (positive sleeve) barrel power jack, 2.1 mm inner diameter, 5.5 mm outer diameter Audio Performance • • • • • • • Maximum Input Level: +6 dBV = 8.2 dBu = 2 V RMS = 5.
Bad cables: Swap out audio cables. USB ground loop: When connected to a computer using a USB cable, noise can appear in the audio signal. This usually results from ground loop noise due to the True Spring and computer running on separate power supplies. In the case of laptops, disconnecting the computer’s power supply and running it on a battery can often mitigate the noise. External display monitors are often the primary source of noise, and powering down monitors can also resolve noise issues.
Mac Gatekeeper Mac users may see this warning message when trying to open the updater software: “App can’t be opened because it was not downloaded from the Mac App Store.” In order to run the updater, please refer to the steps in this Apple support article: https://support.apple.com/en-us/HT202491. Rubber Feet The C4 Synth comes standard with a flat aluminum bottom, making it easy to apply Velcro and mount to a pedalboard. Additionally, adhesive rubber feet are included in the C4’s box.
Warranty Limited Transferrable Warranty Source Audio, LLC (hereinafter “Source Audio”) warrants that your new Source Audio One Series C4 Synth, when purchased at an authorized Source Audio dealer in the United States of America (“USA”), shall be free from defects in materials and workmanship under normal use for a period of two (2) years from the date of purchase by the original purchaser. Please contact your dealer for information on warranty and service outside of the USA.
Disclaimer and Limitation of Warranty Do not open the effects pedal under any circumstance. This will void the warranty. The foregoing limited warranty is the only warranty given by Source Audio and is in lieu of all other warranties. All implied warranties, including warranties of merchantability and fitness for any particular purpose, exceeding the specific provisions of this limited warranty, are hereby disclaimed and excluded from this limited warranty.
