VC – Digital Signal Processor
The Z-DSP is an open-source, cartridge-based, digital sound processing and generating platform for your modular synthesizer. The Z-DSP has a stereo DSP processor with 24-bit sampling, 15Khz of bandwidth, smooth voltage controlled parameters, and has the ability to be programmed all in Eurorack format. While the Z-DSP cannot compete with the processing power found on personal computer, it does provide direct control of the DSP hardware and has a unique set of features aimed at the manipulation of digital effects. With the Z-DSP, digital audio can be bent, stretched, deformed, and distorted by interacting with your modules; something personal computers just can’t do.
The Z-DSP interface VC digital parameters, VC Mix/Dry, manual and sequential program switching, and a pair of VC feedback loop paths with exposed patch points that let you insert the rest of your modular into the DSP process. The Z-DSP lets you go far beyond ordinary processing, breaking the rules and allowing you to patch right into the heart of the DSP chip trough the clock input, allowing for some digital madness and creative sounds design.
Size: 28HP – Depth: 59mm – Power: +12V 130ma / -12V 36ma
Dragonfly MKII is a set of eight voltage controlled time-based delay effects for the Z-DSP MKII features advanced delay programs with added filters and additional taps spicing up the original Dragonfly set of programs further ahead.
With up to 1000ms of delay time and feedback control on each program, the Dragonfly MKII is perfect for deep stereophonic spacey washes of sound covering all delay effect duties within a modular and more.
The external feedback loop on the Z-DSP let you feedback through other modules like filters, VCAs or just about any other module to further process the Dragonfly repeats.
Hook up a Z3000 for a variable clock of the DSP processor chip to mesh up the algorithms processing speed from clear digital repeats to grungy lo-fi warbles, this is where binary DSP bits meet up with the organic analog circuity of the Z-DSP.
The Dragonfly Delay contains the following algorithms:
– Mono in Stereo out L/R Tap: Two taps on a mono delay time
– Mono in Stereo out Lowpass + Feedback: Two delay taps with LPF in feedback
– Mono in Stereo out Highpass + Feedback: Two delay taps with HPF in feedback
– Mono in Stereo out Right Ratio: Selector for ratio of Right delay time lo Left
– Mono in Stereo out Ping Pong: Two tap delay from Left to Right with Low Pass
– Stereo in Stereo out L/R Delay: Independent delay lines on Left and Right
– Stereo in Stereo out Highpass + Feedback: Two delay lines with HPF in feedback
– Stereo in Stereo out Lowpass + Feedback: Tow delay lines with LPF in feedback
Grain De Folie
Granular Synthesis uses small slices of sounds (grains) to compose new sounds from existing material. By combining multiple grains of differing lengths, amplitude, pitch and speed new sounds are created which are often very different from the original sound recorded in. Xenakis claims to have invented the technique and indeed his “Analogique A-B”, composed of tiny tape splices of pure tones, is credited as the first piece of granular music back in 1959.
In the context of the Z-DSP, a block of memory is set to hold digital samples for playback: the Z-DSP has one second of memory for the audio used in processing. From this audio buffer the grains will sample and modify smaller section for playback. The number of grains in the process determine how dense the overall output sounds. These programs have 3, 4 or 6 grains for playback. Each grain plays from a random point in the audio buffer and have an independent envelope controlling their duration. The envelope time is the “grain size” parameter in many of the programs.
The French phrase for the cartridge is “Grain de Folie” which could be translated ad “seeds of madness”, but in French “grain” also translates to “grain” and “madness” evokes the strange disassembling/reassembling granular process. Also, “avoir un grain de folie” is a typically expression to describe people behaving in a non conventional way, thus a fitting play on words quite nicely describing the unpredictable nature of this set of algorithms.
Pitch shifting in the Z-DSP uses a technique called “rotating tape head” delay lines named after pioneering tape based experiments in Germany in the 1960s. The tape heads mote at speeds independent of the tape playback path and two heads are crossfader to make a continuous output capable of beautiful pitched delay effects, harmonization and smooth reverbs.
These pitch shifting algorithms are much like the earliest digital pitch shifters released. Sounds similar to the eventide H910, AMS 15-80 (with Pitch beard) and Publison DHM 89 can be achieved. These programs are intended more for pure effects rather than the complex multiple harmony lines later devices and plugins became known for producing. Chords fomr single VCOs can easily be made using the “Interval” programs on the card though.
Using a Z3000 to clock the Z-DSP, complete chaos from the delay lines and pitch shifting emerges, creating great and unexpected new sounds. Modulating the stereo pair of analog VC-Feedbacks animated the times and distance of the pitch shift opening up these algorithms for additional control from CV and audio signal alike.
Chorus effects for the Z-DSP thicken incoming sound and create animation within the sound’s harmonic structure. In addition, they provide an excellent tool for mono to stereo processing of any incoming sound, or even a whole mix, producing a stereo widening effect.
the card contains eight digital algorithms inspired by a set of the most classic analog Chorus effect ever to be make like the Dimension D, Solina ensemble and some very rare devices as well. True to the modular spirit, the control parameters offer a wide range from subtle and smooth, to fast LFO modulation sea sick wobbles, with a lot of sweet spots in between.
Using the Z-DSP’s own stereo analog feedback path to apply feddback to the effects result in beautiful lush and organic animated drones. Using those feedback inputs as an edditional 2 input channels of direct injection into the DSP chip, the Z-DSP can take up to 4 external sources for generating impressive stereo drones with a classic Chorus touch. The end result is a great tool for the design of atmospheric sounds completely in the modular environment.
Clocked Delays are a collection of eight stereo delay programs that let you sync delay time to an external clock applied to CV input two of the Z-DSP.
With a quick setup, the clock input easily and exactly synchronizes the delay repeats to external rhythms generated by the Trigger Riot, Circadian Rhythms or other clock sources. a Divide parameter is included with each program to switch between different division of stereo ratios creating a spatial audio clock divider which automatically matches the repeats to a playing beat. Feeding the clock input with odd clock division like from the Trigger Riot has the interesting effect of moving the repeats in relation to the playing beat.
When it comes to their sound, some of the programs feature a pristine classic delay lines, while other programs insert a colored band pass, low pass or high pass filter in the feedback loop, imparting a beautiful harmonic transition to the repeats as they feedback through the filter and slowly decay away. Using the Z-DSP’s analog feedback path adds additional voltage controlled stereo feedback which can slightly drift the repeats out of their tight sync to the incoming clock, due to the DSP chip latency, and also extend the delay tail intesity up to self oscillation. Controlling the Z-DSP’s DSP chip speed externally via the Clock jack can devolve everything into glitchy out of sync binary chaos.
Spring Waves brings a set of Physical behavior modeling algorithms to the Z-DSP. It dives deep into experimental digital sound design techniques known as Waveguide Synthesis: a 1998 patent of Stanford University developed by Julius O. Smith III and step forward from Karplus-Strong techniques. In addition to that are two Spring models space synthesis making real Newtonian physics calculation at sample rate.
The principle behind these algorithms is basically a mathematical feedback formula excited by external signals which self oscillate as a damped tone. The type and harmonic content of the external signals these algorithms can react to is extremely wide and so are the tones that they can impart to a sound.
The card contains six Karplus-Strong and tow Spring models. When fed with an external pulse or bursts of noise they self oscillate creating synthetic sounds similar to glass, spring, bell and variety of string tones. When structured sounds like high pitched FM tones, drones, drum sounds and vocals pass through they get a harmonized type effect, many times in an unexpected way. This card is anything but standard as it takes the natural “springy” artifact of digital audio, and, instead of fighting to eliminate it, actually makes use of it as a new source of sound inside the modular.
Numberz is a USB device that communicates with a software front-end (for PC) and can be used to download DSP programs and display text to blank, non-volatile cartridges for use with the Z-DSP. Numberz can also feed directly into the Z-DSP’s cartridge socket for realtime programming.
With Numberz you can:
– Download free Z-DSP programs from the web and “burn” them into cartridge
– Modify programs for new and interesting effects
– Write and Debug Z-DSP programs in a real-time environment
– Share your programs online with other Numberz user
– Share your programs on Z-DSP Cartridges with other Z-DSP user
– Create your own text for the Z-DSP LCD display
The Z-DSP blank cartridges are rewritable memory cards for use with Numberz and the Z-DSP with up to 1 million erase/write cycles. These cards are made of printed circuit board with two (2) memory chips solder on their bottom side providing a low cost non volatile memory of Z-DSP programs and Z-DSP display data.