In the ever-evolving world of audio equipment, a resurgence of interest in analog sound manipulation devices has emerged, marked by two notable products that highlight both innovation and nostalgia in audio engineering. The first is a 3-band graphic equalizer designed by Gabriel Dantas, while the second is the HEX row, a desktop stereo analog filter FX unit from HEX Haus. Both products cater to audiophiles and music creators, showcasing advancements in technology while also appealing to traditional sound design.
Many years ago, audio equipment came equipped with a simple tone control, a basic RC filter that allowed users to adjust the bass to their liking. Over time, this functionality evolved. Initially, the tone control was divided into two separate controls for bass and treble, and eventually into three: bass, mid, and treble. As audiophile trends shifted towards graphic equalizers, these tone controls were rebranded as “3-band graphic equalizers,” a term that some consider misleading. However, Gabriel Dantas has taken the concept of the graphic equalizer a step further with his new design.
According to an article published by Hackaday on April 8, 2025, Dantas’s circuit employs active filters rather than the simple passive networks found in older, budget audio systems. His design includes a low-pass, a bandpass, and a high-pass filter, all built around TL072 FET-input op-amps. Additionally, an LM386 output stage is included to drive headphones, ensuring that the final product delivers quality sound. The project is housed on a home-made PCB, complete with a mains power supply, making it accessible for enthusiasts looking to enhance their audio experience.
While audiophiles often seek out more exotic components for their gear, the article suggests that even with standard parts, Dantas’s equalizer is likely to produce impressive sound quality. This revitalization of tone control reflects a broader trend in audio engineering: the desire for greater control over sound and a more hands-on approach to music production.
On the other side of the audio innovation spectrum is the HEX row, a new desktop stereo analog filter FX unit that offers a unique approach to sound manipulation. This device is available in both assembled and DIY versions, catering to a range of users from hobbyists to professionals. Launched as the third unit in HEX Haus’s series of small synthesizer projects, HEX row builds on previous offerings such as Cor, a touch digital polysynth, and Lag, a multi-FX processor that includes modeled analog bucket brigade delay effects, pitch-shifting, and downsampling.
HEX row features two channels, each with the same signal path topology. The inputs are directed into a gain stage before passing through the filters. Each channel can be controlled using three potentiometers: gain, frequency, and resonance. The gain control allows users to either attenuate or amplify a signal by up to 20 times, which significantly affects the filter’s behavior. This means that at high gain settings, users can achieve self-oscillation sounds and other unique sonic artifacts.
Furthermore, the HEX row includes a side-mounted switch for selecting between lowpass and bandpass modes, adding to its versatility. The center knob filters the left channel’s post-gain signal, which is then fed into an envelope follower, allowing for dynamic sound shaping. This feature enables users to create ducking and gating effects, enhancing the device's utility in live performances or studio settings.
One of the standout features of the HEX row is its three distinct signal path topologies: feedback, serial for twin peak and auto-filtering effects, and parallel for stereo filtering effects. This flexibility allows musicians and sound designers to explore a wide range of audio textures and effects. The unit is also equipped with a golden touch pad, providing manual control over audio routing and voltage control, further expanding its capabilities.
The HEX row operates using a USB-C power supply or a power bank, making it a portable option for musicians on the go. Priced at €159 for the assembled version and €109 for the DIY model, it offers an affordable entry point for those looking to delve into the world of analog audio processing.
In a review of the HEX row, the author expressed a long-standing desire for more stereo analog FX boxes on the market, noting that this product delivers a distinctive and raw sound that sets it apart from competitors. The integration of advanced features alongside its affordability makes it an attractive option for both seasoned producers and newcomers to sound design.
As the audio landscape continues to evolve, products like Dantas’s graphic equalizer and the HEX row filter FX unit demonstrate a commitment to innovation while honoring the roots of audio manipulation. These devices not only enhance the quality of sound but also empower users with greater control over their audio creations.
In conclusion, the resurgence of interest in analog equipment and the development of sophisticated sound manipulation tools signal a vibrant future for audio enthusiasts. Whether through the precision of a graphic equalizer or the versatility of a filter FX unit, these innovations offer exciting possibilities for music production and sound design.
