callback(audio)
products
Get four FX processing apps released by Callback Audio! VST3 and AU support on macOS and Windows, plus Standalone and AUv3 on iOS. An effective set for sculpting, mangling, and expanding your sound palette.
Bundle includes:
- Bit Crusher — Quantizer & Decimator
- Delay Line — Digital Delay Effect
- Multimode Ladder Filter — LP/HP/BP/Notch/Res Filters
- Wavefolder — Harmonic folding distortion
A 4-pole (24 dB/oct) ladder filter modeled after the topology designed by Robert Moog in 1965. Four cascaded one-pole stages with tanh saturation at input and feedback produce warm analog-style distortion that scales with drive and resonance.
Five filter modes (lowpass, highpass, bandpass, notch, and resonant) cover everything from classic subtractive sweeps to sharp self-oscillating leads. Resonance drives the filter to self-oscillation at high values, generating a sine tone at the cutoff frequency. A dry/wet control enables parallel filtering.
A classic algorithmic reverb based on the Freeverb algorithm by Jezar at Dreampoint, using the classic Schroeder/Moorer topology of 8 parallel comb filters and 4 series allpass filters. The network creates lush, spacious ambience with a smooth, musical reverb tail.
Freeverb is widely used in electronic music production, ambient music, and sound design to add depth, space, and atmosphere — working equally well on vocals and synthesizers. This implementation uses simplified controls and runs in mono with no stereo spread, otherwise behaving like a classic Freeverb.
A digital degradation effect that combines two classic forms of lo-fi distortion: bit depth reduction (quantization) and sample rate reduction (decimation). Together they emulate the character of early digital samplers, 8-bit consoles, and vintage hardware with limited converter resolution.
The signal is first quantized to a reduced number of bits, introducing the harsh harmonic distortion known as quantization noise. It is then resampled at a lower effective rate using a sample-and-hold stage, producing aliasing artifacts above the new Nyquist frequency.
A nonlinear distortion effect that reflects signal peaks back into the audio range, creating rich harmonic content. Wavefolding is widely used in modular synthesis and experimental music production to add character, aggression, or shimmer to sound sources.
Unlike simple hard clipping, which crushes transients, wavefolding preserves amplitude information by folding back on itself. Control the fold amount and bias to shape the harmonic spectrum from subtle saturation to extreme metallic textures. A dry/wet control enables parallel processing.
A high-quality digital delay effect with smooth parameter interpolation and feedback control. This delay provides clean, musical echoes perfect for adding depth and space to your audio.
The delay uses linear interpolation for smooth delay time changes and includes comprehensive parameter smoothing to eliminate zipper noise during real-time parameter adjustments.
A PCM synthesizer that turns arithmetic expressions into audio in real time. Type an expression using the sample counter t and standard operators. The engine evaluates the expression at sample rate and plays the lowest bits as raw PCM.
Bitwise AND, OR, XOR, and shifts combine multiple time scales into melodies, rhythms, and timbres from a single line of math. Arithmetic overflow and natural wrapping at 8, 16, or 32 bits produce the characteristic sound. A custom operator keyboard, waveform scope, and built-in reference make it a self-contained environment for exploring this form of synthesis.
A Max for Live device rendition of Pauline Oliveros' Tape Delay Feedback System designed in the 1960s, as documented in Figure 9 her article in "Tape Delay Techniques for Electronic Music Composition". Control over 4 tracks of amplitude and delay time. Changing delay time clears the signal path and "restarts" the system.
The device takes in mono or stereo (mixed to mono) and each dial allows the user to control input gain, feedback intensity and output gain of each channel. This is the model of the system that she used in David Tudor's Light Piece.