The Gieskes LFSR2R Eurorack module is a distinctive embodiment of function and novelty. Operating as a Sequencer, LFSR Noise generator, and Semi random CV generator, the module dives deep into the world of rhythm and patterns. The name "LFSR2R" stands for 'Linear Feedback Shift Register' (LFSR) plus 'Resistor Network' (R/2R), combining two powerful technologies within a single casing. A Resistor Network R/2R is an integral component used to convert digital binary outputs into analog voltages—a process commonly employed in Digital Analog Converters (DACs). This crucial transformation births an array of rhythmic patterns and melodies suitable for drum sequences.
The journey to create this module was inspired by a need for a sequencer that perfectly complements drum modules, especially those like vu-perc. These modules respond to gate signals; their velocity varies depending on the voltage level of the gate signal—higher voltage engenders a stronger hit and vice versa. The LFSR2R module comes with a CV input that modulates the voltage emanating from all gate outputs, thereby providing control over the volume of the vu-perc modules.
Gieskes offers two versions of the LFSR2R module: one version with LEDs piercing through the top of the panel (THT) and another with LEDs that illuminate the PCB from the back (SMD). Both versions have their unique aesthetic appeals and practical uses. During the module's design phase, insights were drawn from renowned designs such as those from Ciat Lonbarde's Plumbutter and Tom Whitwell's Turing-Machine.
The decision to develop a 4015 sequencer instead of a simplistic 4017 allowed for subtle articulations and intricate movements within the sequence. Equally important was the conscious choice to refrain from digital features, thereby preserving analog simplicity and encouraging a natural muscle memory interaction with the module.
Digging into the specifications, the LFSR2R SMT module is 4cm (8hp) wide, consuming +90mA -10mA power, while the LFSR2R THT module is of the same width but consumes slightly lesser power at +50mA -10mA. Both modules, along with their respective expanders, have a depth of approximately 2.5cm with the power cable connected. The adjustable voltage outputs range from 0 to +10v in both the R2R output and at the active steps of the sequencer.
Notably, the clock inputs integrated with Schmitt Triggers for security switch from around 0.8v to 2v—a design framework that can handle even audio signals. However, using clock signals is preferable. Schmitt Triggers are instrumental in preventing data loss in the middle of the sequence. The unique toggles and buttons present, such as the DATA Red Button for manual data input like the TR-808 tap function and switches to manage DATA erasure are key features for streamlined sequence management.
Lastly, the DATA and XOR inputs offer versatility in creative sequencing. Employed singly, they function as DATA inputs, but when used together, they form a XOR input. A toggle switch near the XOR input enables or disables it—an important feature when maintaining or modifying sequences. Ensuing from these well-integrated design decisions, the Gieskes LFSR2R vividly unlocks the potential for sophisticated rhythmic complexity within your Eurorack setup and across the sonic landscape. Its commitment to simplicity, creative modulation, and rhythmic flexibility make it an invaluable tool for those seeking to dive deeper into the endless ocean of sound experimentation and musical creativity.
Example Usage
To tap into the potential of the Gieskes LFSR2R for enhancing rhythmic complexity as a novice, let's start by using it as a basic sequencer with semi-random characteristics. The Gieskes LFSR2R is an intriguing choice for creating dynamic percussion patterns, thanks to its blend of linear feedback shift register functionalities and resistor network DAC output.
First, connect the clock signal from a reliable source, such as a steady LFO or a clock divider, to the clock input of the LFSR2R. This will drive the internal sequence, activating step progression. Make sure the clock signal is clean; utilizing the Schmitt Trigger within the module helps ensure stability by cleaning up jittery clock edges.
Next, use the R/2R output to modulate the pitch of a basic VCO. This setup will allow you to hear the melodic output of the sequencer as it steps through its cycle. Since our focus is on rhythm, patch this output to control the amplitude or timbre of a percussive module like the vu-perc, as mentioned in the module's manual. The varying gate levels from the sequencer will cause subtle differences in each percussion hit, bringing life to your rhythm patterns.
Activate the DATA input using an external gate or manual push with the red button provided. Play around with this to inject random bits into your sequence, altering its progression. This hands-on interaction is a fantastic way to appreciate the improvisational capability of the LFSR2R. To maintain your favorite unexpectedly successful pattern, use the XOR toggle switch to loop the current sequence, effectively freezing the randomization to work as a traditional looped sequence.
Explore using the XOR input creatively by splitting your clock signal and feeding it into multiple inputs, toggling the switch to engage or disengage parts of the sequence involving XOR logic. This can lead to new rhythmic nuances without adding complexity to your input signal.
Finally, if your module has the THT version, enjoy the visual feedback from the protruding LEDs, which give you a quick glance at sequence activity. If you have the SMD version, pay attention to their glow for insights in a darker environment as ambient lighting may wash out their visibility.
In this way, you'll begin to appreciate how the Gieskes LFSR2R can transform simple rhythmic concepts into complex, evolving patterns, unlocking new dimensions in your sound design journey. Whether you're performing live or composing in the studio, these techniques can dramatically increase the depth and texture of your percussive sequences.
To fully leverage the Gieskes LFSR2R Eurorack module and unlock its potential for creating intricate and expressive rhythmic patterns, it's essential to understand its functions and interactions. This intermediate-level example assumes familiarity with basic patching techniques and modular synthesis concepts.
Let's dive into the multifaceted nature of the LFSR2R, especially focusing on its ability to generate semi-random CV and trigger signals that can be creatively harnessed to produce evolving rhythmic sequences.
Begin by setting up your primary clock source. Connect it to the Clock input of the LFSR2R. This clock signal will act as the heartbeat of your pattern, advancing the LFSR's internal sequence and output stages with each pulse.
Engage the XOR and DATA inputs to infuse randomness into your sequence. Connect a low-frequency oscillator (LFO) to the XOR input to introduce a fluctuating voltage that modulates the sequence. Experiment with different LFO waveforms and rates to observe how they alter the sequence's progression. By adjusting the toggle switch associated with the XOR input, you can maintain a repetitive loop by disabling this randomness or let it continually evolve.
The red DATA button is another powerful tool at your disposal for real-time intervention. Tap the button rhythmically to manually insert data points into the sequence, akin to a TR-808 tap tempo, allowing spontaneous creation of new beats.
Clock outputs from the LFSR2R can directly trigger percussive modules or drive other sequencers. Connect the Clock outputs to a drum module or another sequencer. Use the module's potmeter to adjust the output voltage, influencing the dynamics and accents of connected modules, like the vu-perc modules that respond to varying voltage levels with different intensities.
Finally, take advantage of the R2R output to generate a continuous or quantized CV sequence. Use this to modulate parameters on filters, oscillators, or effects, creating complex, intertwined rhythmic evolutions within your patch.
By combining these techniques, the Gieskes LFSR2R becomes a versatile tool in creating intricate, living rhythmic patterns that can transform your modular system into a dynamic rhythm machine, offering endless possibilities for rhythmic exploration.
Further Thoughts
To harness the rhythmic complexity of the Gieskes LFSR2R, one should first comprehend its dual nature as both an LFSR noise generator and a sequencer, enabling intricate, semi-random patterns suitable for experimental percussive tracks. The module's LFSR, or Linear Feedback Shift Register, creates sequences through binary patterns that seem random yet are predictable, offering a new edge to your modular setup.
Begin by exploring its sequencer capabilities. Connect your clock source to the Clock Input to initiate the sequencer. The Schmitt Trigger within the input ensures stability by filtering any extraneous noise that could disrupt the shift register's timing, providing reliable performance even with noisy signals or audio rates. Utilize the top potmeter to set the voltage range for active steps, enhancing dynamics in your rhythmic pattern.
Use the DATA and XOR inputs to introduce variance into your sequence. By feeding voltage above 0.6V, your input transforms into a binary "1," altering the sequence significantly. For additional creative control, engage the toggle switch beside the XOR input: when engaged, it permits XOR functionality, providing the ability to generate more complex sequences or to freeze an existing sequence by looping it.
For hands-on modulation, employ the DATA Red button to tap in rhythm ideas manually, reminiscent of classic drum machines like the TR-808. Moreover, manipulating the toggle switch labeled "Erase DATA" offers control over data flow into the shift register. Erase unwanted patterns by setting it momentarily or permanently; remember, permanent erase will require up to eight clock cycles to fully clear existing data.
Unleash the power of the R/2R network by converting these binary outputs into varied voltage signals suitable for driving drum modules such as the vu-perc. Adjust the CV input to modulate the voltage of all gate outputs, thereby controlling the intensity of your percussive hits. This feature is particularly advantageous for creating dynamic grooves where each hit's force differs, providing life and movement to your composition.
For aesthetic and practical considerations, decide between the THT version with protruding LEDs for enhanced visibility or the SMD version for a sleek, PCB-mounted look. Your choice will depend on your studio environment and need for visual feedback during performances.
By understanding and mastering these features, the Gieskes LFSR2R becomes not just a module, but a powerful tool for sonic exploration, giving you intricate rhythmic patterns that push beyond the boundaries of typical drum sequencing.