SEMSVF, handcrafted by G-Storm Electro, has successfully captured the essence and gritty texture of the iconic Oberheim SEM State Variable Filter and encapsulated it into a versatile Eurorack module. This filter, with its creamy and silky response, is nothing short of a Eurorack marvel, setting the bar high with its characteristically smooth resonance feedback circuit and remarkable 3080 OTA design.
By utilising obsolete NOS FETs at each stage, SEMSVF dishes out an unparalleled filter response that offers a delightful dance between lowpass, notch and highpass modes. This module, available in tribute and noir editions, reflects a musical charm that pays homage to the iconic Oberheim filter, in both sound and aesthetics.
The foundation of the SEMSVF module is its frequency and resonance controls. The initial cutoff frequency can be adjusted through the Frequency knob, and the depth of the peak frequency resonant feedback through the Resonance knob. Interestingly, this module doesn't self-oscillate without an input signal, adding a layer of excitement and unpredictability.
SEMSVF excels in adaptability with its two distinct audio signal inputs, each complete with their mix pot. You can mix together two different audio signals, creating unique soundscapes and playful sonic interplay. Furthermore, the modular design of the SEMSVF allows for seamless integration and interaction with other modules in your Eurorack system.
The true beauty of SEMSVF lies in its modulation capabilities. The bi-polar nature of the MOD knob allows for the modulation of the cutoff frequency with any polar and bi-polar signal. The KB knob, on the other hand, is designed to modulate the cutoff frequency with a V/oct signal or even other polar or bi-polar mods. When set to 100%, the self-oscillation resonance will track V/Oct, increasing the potential sonic possibilities.
The addition of the Notch knob allows for sweeping the response from lowpass, through notch, to highpass on the LP|HP Output. An external modulation can also be used to control this mix using the LP|HP CV knob. The audio output jacks of the LP|HP|Notch and BP filter tap also allow for creative experimentation with the filter taps.
In conclusion, SEMSVF is indeed a king amongst Eurorack filters, boasting an inspirationally creamy and silky filter response, efficient signal input mixing, adjustable frequency and resonance controls, and excellent CV modulation capabilities. Its iconic tribute to the SEM Filter along with its beautiful design make it a highly desirable and coveted asset to any Eurorack system.
In this example, we'll explore how to use the SEMSVF module to create a dynamic filter sweep effect.
To begin, let's connect our audio source to the IN#1 input and another audio signal to the IN#2 input. Adjust the mix pots to blend the two signals together to your desired balance.
Next, we'll manipulate the filter cutoff frequency using the FREQUENCY knob. Turn it clockwise to increase the cutoff frequency and counterclockwise to decrease it. This will shape the overall tonal character of the filtered sound.
Now, let's add some modulation to make things more interesting. Take a polar or bipolar signal and connect it to the MOD input. This can be an LFO, envelope, or any other modulation source. Rotate the MOD knob to set the depth of modulation. At 12 o'clock, the knob has no effect, and turning it counterclockwise can even invert the modulation signal.
If you have a keyboard or any other V/oct signal generator, you can use it to modulate the cutoff frequency by connecting it to the KB input. Set the KB knob to 100% to ensure that the self-oscillation resonance tracks the V/oct signal accurately.
To further shape your sound, use the RESONANCE knob to control the depth of peak frequency resonant feedback. Experiment with different settings to achieve the desired level of resonance. Bear in mind that without an input signal present, the resonance will not self-oscillate.
Now, let's explore the LP|HP|Notch mix sweep control. This control allows you to sweep the filter response from lowpass to notch and highpass on the LP|HP output. Use the LP|HP CV input to add external modulation to this mix. The LP|HP CV knob amount is summed with the NOTCH knob (initial mix setting) above it.
Finally, connect your audio output to either the LP|HP OUT jack for the filtered sound or the BP OUT jack for the bandpass-filtered sound.
Remember, the SEMSVF is a versatile module, so feel free to experiment and tweak different parameters to create unique and expressive filter effects in your Eurorack system.
Intermediate-Level Usage Example:
One interesting way to use the SEMSVF is in creating evolving and dynamic basslines. Start by sending a monophonic sequence from your sequencer into the IN#1 input of the SEMSVF. Then, connect a LFO (low-frequency oscillator) to the MOD input, modulating the Cutoff Frequency. This will add movement and variation to the bassline. Next, take the LP/HP output and run it through a delay effect module for added depth and texture. Finally, experiment with the RESONANCE knob to find the sweet spot where the filter adds just the right amount of character to the bassline. By adjusting the NOTCH knob, you can further shape the timbre by sweeping between lowpass, notch, and highpass responses. This technique will give your basslines a creamy and silky quality, elevating them to a professional level.
Expert Usage Example:
The SEMSVF module is a true gem when it comes to eurorack filters, and its creamy and silky sound makes it a standout choice for any modular setup. Let's dive into a creative usage example to showcase the versatility of this king of filters.
Imagine you have multiple oscillators generating rich and complex waveforms, and you want to create a dynamic and evolving sound. You patch one oscillator into IN#1 and another into IN#2 of the SEMSVF module, blending their signals using the mix pots. This allows you to create a unique blend of harmonic content from the two oscillators, opening up a world of sonic possibilities.
Next, you decide to modulate the cutoff frequency to introduce movement and rhythmic variations. You use a random LFO as the modulation signal and patch it into the MOD input. By turning the MOD pot counter-clockwise, you invert the incoming control signal, adding an extra dimension of randomness to the modulation. Now, the SEMSVF responds to the random fluctuations of the LFO, modulating the cutoff frequency and creating a constantly evolving texture.
To add some melodic variation to your patch, you also patch a sequencer into the KB input, controlling the cutoff frequency with a V/oct signal. With the KB knob set to 100%, the SEMSVF tracks the incoming V/oct sequence, allowing you to create melodic lines that interact with the harmonics of your sound source.
But what if you want to shape the frequency response in a more intricate way? This is where the notch feature comes in. By turning the NOTCH knob, you sweep the response from lowpass to notch and highpass, accessing a wide range of filtering options. Moreover, you can use external modulation by connecting a source to the LP|HP CV input, allowing you to dynamically control the mix of lowpass, highpass, and notch outputs.
The SEMSVF module truly shines when it comes to producing rich and expressive textures. Its combination of creamy filter response, extensive modulation options, and notch feature provides endless possibilities for sound sculpting and experimentation. Whether you're creating atmospheric pads, pulsating basslines, or intricate soundscapes, the SEMSVF is a powerful tool that will elevate your eurorack system to new heights.