Digital Multi-Effects
The C99 is a low-latency digital stereo multi-effects pedal containing dual three-stage preamps/overdrives, dual tone stacks each with three semi-parametric EQ's, dual delay/modulation blocks for delay+flanger+chorus, dual plate reverb, dual impulse response based cabinet/speaker simulators, and dual 'blooper' blocks with some strange effects inspired by the ChaseBliss Blooper.
All effects blocks have two channels (A and B) with their own settings and can be mixed to the left/right outputs to create stereo separation, or to create complex mono effects.
The speaker/cabinet simulator (impulse response convolution) allows the pedal to be used without a guitar amplifier; connected to powered speakers or a PA system. USB audio support allows the C99 to act as a USB recording interface as well as a USB audio sound card supporting effects audio and USB audio mixing.
Effects Chains
The C99 implements two completely separate effects chains. Each effects chain consists of a three-stage preamp/overdrive, tone-stack, modulation/delay, reverb, impulse response based cabinet simulator, and a bloopers block. Each effects chain has its own parameters and can be used in parallel to provide a stereo effects system or a dual mono effects system using the internal mixer.
Preamp Block
The preamp block consists of two (A and B) 3-stage amplifier models similar to that of a tube preamp circuit in a guitar amplifier. Each stage incorporates soft tube-like clipping as well as pre and post tone shaping resulting in a final preamp output that's smooth and articulate.
PREAMP - PRE LOW-CUT: Reduces the bass (response before clipping) for each preamp stage. Use this control to loosen or tighten up the amp's bass response.
PREAMP - MID-EMPHASIS: Emphasizes the mid-range response of each preamp stage. This control cascades the mid-range gain of the increasingly distorted guitar signal resulting in a brassy overdriven sound. Use the tone-stack's middle frequency control to cut the midrange for a great classic hard rock sound.
PREAMP - EMPHASIS FREQ: Adjust the center frequency of the mid-emphasis control.
PREAMP - STAGE GAIN: The amount of signal gain for each stage. Increasing the gain increase the amount of clipping (similar to tube saturation).
PREAMP - POST HIGH-CUT: Reduces the treble after the last preamp stage, similar to a tone control on an effects pedal.
Tone/EQ Block
The tone block consists of two (A and B) three-band semi-parametric equalizers with adjustable EQ gain and frequency settings with the filter Q being adjusted automatically to result in a smooth and natural frequency response shape between adjacent EQ bands. The tone stack equalizers operate primarily on the lower, middle, and upper midrange frequencies therefore the preamp's 'PRE LOW-CUT' and 'POST HIGH-CUT' controls are used to adjust the bass and treble levels.
EQ 1 - GAIN/FREQUENCY: Adjusts the gain and the frequency of the semi-parametric EQ for the lower frequencies (lower-midrange). The Q is adjusted automatically to blend smoothly with adjacent EQ bands.
EQ 2 - GAIN/FREQUENCY: Adjusts the gain and the frequency of the semi-parametric EQ for the mid-range frequencies (middle mid-range). The Q is adjusted automatically to blend smoothly with adjacent EQ bands.
EQ 3 - GAIN/FREQUENCY: Adjusts the gain and the frequency of the semi-parametric EQ for the upper frequencies (upper midrange). The Q is adjusted automatically to blend smoothly with adjacent EQ bands.
Delay Block
The delay block consists of two independent delay lines (A and B) each with their own own delay line lengths and modulation frequency oscillator (LFO). Using short delays with feedback results in flanging, medium delays with no feedback and some delay modulation results in chorus, and long delays with or without feedback results in slap-back with or without echoing. The delay can also be used to hold off reverb resulting in a 'large room' reverb sound.
DELAY - SOURCE: Pans this delay block input between the outputs of tone blocks A and B. A setting of 1 selects the output of tone block A, 50 blends the tone block A and B outputs together (50% each), and 99 selects the output of tone block B.
DELAY - TIME: Sets the base delay time for the delay line (0 to 300 milliseconds). Use the modulation parameters to modulate the delay to create flanging and chorus sounds.
DELAY - MOD RATE: Sets the delay time modulation frequency for delay line #1 (0 Hz to 3 Hz).
DELAY - MOD DEPTH: Sets the delay time modulation depth for delay line #1 (0% to 10%).
DELAY - FEEDBACK: Adjusts the amount of delayed signal that is fed back into the delay line. Moderate feedback with short delay times result in flanging. Low to no feedback with moderate to high delay times result in chorus.
DELAY - TIME: Wet/dry blend ratio. A setting of 1 is dry, 50 is 50% dry and 50% wet, and 99 is wet.
Reverb Block
The reverb block consists of two (A and B) reverb engines that implement the reverb algorithm as described by Jon Dattorro (AES Member. CCRMA, Stanford University, Stanford, CA, USA). This implementation provides a plate-style reverb with adjustments to effect the reverb tail decay and echo density.
REVERB - SOURCE: Pans this reverb block input between the outputs of delay blocks A and B. A setting of 1 selects the output of delay block A, 50 blends the delay block A and B outputs together (50% each), and 99 selects the output of delay block B.
REVERB - REFLECTION: Increases the amount of reflection resulting in slower reverb decay.
REVERB - DAMPING: Increases the smearing of each reflection and reduces the higher frequency response of the reflections. Use this to reduce the brightness of delay effects. More diffusion will give the impression of shorter delays due to the high frequency attenuation of reflection. Less diffusion will leave the frequency response less affected resulting in metallic and long lasting reverb, especially with the reflection turned up.
REVERB - TIME: Wet/dry blend ratio. A setting of 1 is dry, 50 is 50% dry and 50% wet, and 99 is wet.
Cabsim Block
The two cabsim blocks (A and B) use impulse responses for convolution based speaker and cabinet simulation - useful for when you need to add the tone and reverb characteristics of guitar speaker/cabinets when direct recording via USB, or when using the C99 with powered speakers or a PA system. A setting of zero results on no cabinet simulation taking place - use this setting to disable cabinet simulation (e.g. when routing the C99 to your guitar amplifier).
CABSIM - SOURCE: Pans this cabsim block input between the outputs of reverb blocks A and B. A setting of 1 selects the output of reverb block A, 50 blends the reverb block A and B outputs together (50% each), and 99 selects the output of reverb block B.
CABSIM - SPEAKER: Selects which authentic Celestion speaker/cabinet impulse response is used - ranges from 1 to 9 (nine impulse responses).
Bloopers Block
The two 'bloopers' (A and B) blocks can be used to create unique old-and-busted variations of the effects chain output. This block was inspired by the ChaseBliss Blooper.
BLOOPS - SOURCE: Pans this blooper block input between the outputs of cabsim blocks A and B. A setting of 1 selects the output of cabsim block A, 50 blends the cabsim block A and B outputs together (50% each), and 99 selects the output of cabsim block B.
BLOOPS - LOWFI: Attenuates both low and high end audio responses.
BLOOPS - RESONANCE: Increases Mid-range resonance (gain of resonant filter).
BLOOPS - NOISE: Adds tape noise/hiss.
BLOOPS - DROPS: Occurrence and duration of momentary audio drops.
BLOOPS - BLEND: Wet/dry blend ratio. A setting of 1 is dry, 50 is 50% dry and 50% wet, and 99 is wet
Output Block
The output block controls the effect chain's output volume and the cabinet impulse response selection. Since these parameters are included in the effects presets, the overall volume and cabinet selection chain can be adjusted per preset.
OUTPUT - VOLUME: Adjusts the output volume before being altered by the master volume (VOL) knob.
OUTPUT - BALANCE: Pans the effects channel (A or B) from 100% left to 100% right.
Impulse Responses
The guitar speaker and cabinet have a significant effect on the overall sound of the guitar and effects chain. Using impulse responses allow a speaker's frequency response, as well as its reverberation characteristics, to be applied to the audio signal to replicate its effect. This is useful for setups that do not include a conventional guitar amplifier and speaker/cabinet such as PA systems or that use of powered studio monitors. In fact, it's possible to sound much like a guitar amp setup without a guitar amp. This is especially useful when using the C99 as your computer's record and play-back audio device allowing the C99 to act as your instrument-to-computer recording interface, your sound-card for music playback, and your multi-effects unit ... all with one compact device!
The C99 contains the following nine authentic Celestion speaker impulse responses built-in:
- Celestion Alnico Blue 1x12 Open Back
- Celestion Alnico Cream 1x12 Open Back
- Celestion Alnico Cream 1x12 Closed Back
- Celestion Vintage 30 1x12 Open Back
- Celestion Vintage 30 1x12 Closed Back
- Celestion Vintage 30 2x12 Open Back
- Celestion Vintage 30 2x12 Closed Back
- Celestion Greenback 4x12 Closed Back
- Celestion G12T-75 4x12 Closed Back
Pedal Controls
The C99 has two modes of operation, normal mode and edit mode, and is controlled with two rotary encoders (with push-buttons) and one foot switch. In normal mode the display shows the volume level (ranging from 1 for minimum volume to 99 for maximum volume), the preset number (ranging from 1 to 9), and the tone setting (1 for maximum treble cut to 99 for minimum treble cut). The volume and tone levels apply to all presets. In edit mode the display shows the name of the selected effect parameter, the current preset selection (1 through 9) and current channel selection (A or B), and the parameter value.
The example above shows the normal mode display with a volume setting of 30, current preset number of 7, and tone setting of 50. The edit mode display example shows the name of the effects parameter block ('preamp'), the name of the effect blocks parameter ('gain'), the currently selected preset and channel (preset number 7, channel A), and the parameter value (50).
In normal mode the foot-switch as well as the right encoder push-button increments the preset number while the left encoder push-button places the C99 into preset edit mode. The left encoder is used to change volume setting and the right encoder is used to change the tone setting.
In edit mode the foot-switch still increments the preset number allowing you, for instance, to select a specific effect parameter and quickly change that parameter's value for different presets. The left encoder is used to select the effect parameter (e.g. scrolling up or down the parameter list for each effects block) while the right encoder adjusts the currently selected parameter's value for the currently selected preset. Pushing the right encoder push-button will toggle between channels A and B allowing you to set the effect parameter value for each channel. Pushing the left encoder push-button will cause the device to exit edit mode and enter into normal mode.
USB/MIDI Interface
USB MIDI allows the C99 to be controlled from a USB host. Google Chrome and the C99.html file can be used to edit the effects presets. Whether editing presets with the knobs/display or with Google Chrome both interfaces will remain updated and display the current preset settings. When preset settings are changed they are automatically saved internally in the C99 - no explicit save action is required. Note that OS X, Linux and Android systems have the USB audio class 2.0 driver built-in while Windows 7/10 require the Thesycon driver available for free from XMOS.
Specifications
Case Design: 3.3" x 2.3" x 1.0" (Very Compact!), CNC precision milled from solid aluminum.
Total Latency: 1.25 milliseconds from analog audio input to analog audio output.
Audio Input: Mono, 1 Vpeak (2V pk-pk), 1 Mohm resistance, low noise differential analog signal path, 24-bit 48 kHz sampling.
Digital Signal Processing: 32/64 bit fixed-point math, 32 bit audio signal, filter and impulse response data, 64-bit intermediate results/accumulation.
Audio Output: Stereo, 1 Vpeak (2V pk-pk), 24-bit 48 kHz sampling.
USB Audio: USB Audio class 2.0, 32-bit sample width, 48 kHz sample rate, stereo input for recording, stereo output (can be mixed with the effect output) for audio play-back, MIDI support for effects control and adjustment.
USB MIDI: Support for firmware upgrading, effects control and adjustment via MIDI SYSEX.
Power Supply: External 9-12V supply (2.1mm barrel, center negative) or USB bus power, the power source is selected automatically. The 9-12V supply is used if both are available.
User Controls: Two foot switches (preset A/B toggle and presets 1-8 selection), two knobs (master volume and effect/USB audio mixer).
Parameter Presets: Seven banks of effects stereo chain parameter presets, presets selectable by foot switches and edited using USB/MIDI base applications.
Cabinet Simulation: Impulse-response processing at 48 kHz supporting 20 milliseconds of convolution per channel. Nine Authentic Celestion speaker/cabinet impulse responses are included.