Radial Q3 Induction Coil Equalizer

The Radial Q3 is a spectacular sounding induction coil EQ that has been formatted to fit the popular 500 series format and the Radial Workhorse. It is designed to accentuate the character of a voice or instrument without introducing the artifacts and phase anomalies commonly associated with typical gyrator (resistor-capacitor) equalizer circuits.

The Q3 features four easy to use controls: top-end boost, mid-range cut, low frequency bass boost and gain make-up to offset the signal loss that occurs when using passive equalization. Each of the three EQ bands employs a 12 position Grayhill switch with a different preset curve at each position. These are carefully crafted to introduce subtle accents, huge hype and warm sounding cuts that will flatter and enthral. Each EQ setting is augmented with a miniature toggle switch that enables you to attenuate the curve for more subtle effects to deliver over 10,000 combinations of tonal bliss. And because presets are employed, it's easy to recreate favourite patches by setting the dials with 'easy to remember' 3-number combinations.

Adapted for use with the Radial Workhorse and older API Lunchbox racks, the Radial Q3 is plug-and-play easy to use. Simply feed it with a balanced line level signal and you are set to go. When connected to a Workhorse, the Omniport is assigned as an effects loop to allow various processing devices to be inserted into the EQ signal chain.

The Q3 induction coil EQ... probably the most exciting equalizer ever… read more made.

Q3 Development

Several years ago, Radial started developing their first coil EQ called the Q6. Back then, they immediately found themselves drawn to the most revered of all designs -- the induction coil equalizer. Coil EQs are renowned for the warmth they introduce into the signal path and reduced phase distortion when pushed to extremes.

Vintage coil EQs such as the Pultec are coveted today due to the way they add warmth to the signal path along with a creamy top end. This is particularly useful with today's often sterile digital recording environment. One challenge with this older design is that has a limited frequency selection. Manley's Massive Passive expanded upon the design by adding additional frequencies, more control and increasing the number of EQ bands. Another challenge is of course cost: not everyone can afford to spend $10,000 to $20,000 on an equalizer.

We took a different approach. Instead of trying to follow the 'clinical approach' of a 'parametric graphic equalizer', they chose to create an EQ that would conjure up spirits! In other words, they wanted to move away from the 'traditional' whereby one selects a frequency, adjusts the width and changes the amplitude. This type of EQ'ing is standard equipment in most digital consoles and software programs.

The original Q6 design and the 500 series Q3 are different. They employ a preset curve architecture that is completely unique. As you get familiar with how the Q3 works, you will quickly find yourself gravitating to specific tones for certain instrument and mic combinations, essentially, creating a secret sauce that can make a snare stand out, a bass solidify or an acoustic guitar shimmer.

Facing the challenges

The challenges with coil EQs are numerous. An induction coil employs an air-filled bobbin that works like a transformer. When current is applied, a magnetic field is generated. This not only causes the coil to generate a magnetic field, but also makes it prone to being affected by outside electro-magnetic forces. This problem is amplified when you try to pack the coils tightly together inside a small box.

During the development stage, they spent months trying to eliminate noise. We discovered that a shielded coil sounds very different from non-shielded one, even though both may share the exact same specifications. The shield actually collapses the magnetic field which in turn changes the tone. We tested dozens of variations until they finally made their choice. But getting the coil you want requires significant resources. You cannot simply buy 'off-the-shelf' coils to do this type of thing. Each of the coils must be custom ordered. And because mechanical switches are required in the design, particular attention must be paid to both the quality of the contacts and the mechanical attributes of the switch.

Developing the feature set

The Q3 employs 9 coils that are combined with various circuits to generate 33 different preset curves. These are separated into three groups with 11 high-frequency boost curves, 11 mid cuts and 11 low frequency boosts along with a bypass position for each band. Three custom ordered USA-made Grayhill switches are employed for the task. Grayhill is considered to be the premier switch manufacturer of compact military grade rotary switches and like all quality devices, cost a bundle. But considering the Radial Q3 will likely play a never-ending role in your studio, longevity will be critical to the performance. With Grayhill switches, you can confidently twist and dial to your heart's content without worry of failure or downtime.

For the most part, the high and low presets are set up to boost frequencies while the mid presets will cut frequencies. This is purposely done following the way humans perceive sound. Back in 1933, scientists Fletcher & Munson demonstrated that the ears are most sensitive to the mid range thus the reason humans naturally gravitate towards 'smile-shaped loudness curves' when they listen to music. By accentuating the highs and lows, and cutting the mids, the Q3 enthrals and enhances the aural senses, captivating the listener with an abundance of character.

Controlling the beast

Approaching the Q3 is easy. Close your eyes and listen. Each curve has been carefully sculpted to create interesting effects. To add even more splice to the soup, three miniature toggle switches enable you to reduce the amplitude of the effect. Point being, what may flatter an acoustic guitar or add crack to a snare drum may be a over the top for a female voice or unusable on flute. Simply 'shift down' to suit.

As you become familiar with the various types of curves in each of the three bands, you will quickly begin to combine curves to create curves. There are just over 13,800 tone combinations (24 x 24 x 24). But don't let this number scare you. The most mind boggling thing about the Q3 is the repeatability of the circuit. Our brains easily remember patterns or short numbers like padlock combinations. Once you find your favorite Fender P-bass slap tone, you will quickly memorize the dials with 8-3-6 for each of the three 12 position switches. Add or subtract to the effect by switching the mini toggle. Or take it one step further by reducing the bass content with the high-pass filter.

Features:

- Coil EQ based on vintage EQs from the golden age
- A stunning combination of over 10,000 tonal variations
- Lets you color your sound with warmth and detail
- Works with Workhorse and all 500 series power racks read less