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Wisdom Audio Low Frequency Regenerators

The Adrenaline Low Frequency Regenerator was designed for today’s requirements of deeper, louder bass, lower distortion, and smaller enclosures. This demands a driver technology that is optimized for hard-hitting audio reproduction. A superior alternative to the common “overhung” voice coil speaker is a driver designed with an “underhung” voice coil. Instead of using a long voice coil in a short magnetic gap, the underhung voice coil motor driver utilizes a short voice coil in a long magnetic gap. There are many advantages.

The underhung driver allows the amplifier to see a constant impedance load instead of a constantly changing impedance load associated with overhung drivers. Distortion is lowered tremendously and a tight, visceral response occurs simultaneously along with less effort for the lower frequency demands placed upon the driver. Piston extension and travel capabilities are increased dramatically while increasing control. The cone weight can be increased allowing the use of stiffer composites. Wisdom also uses a copper sleeve insert to evenly spread the magnetic flux density over the entire 3” travel area. This gives the driver composure at any cone travel distance within the 3” excursion area. The only downsides are that the motor magnet must be enormous (over 40lbs.) and the cost to build skyrockets.

Since the magnetic force on the coil is constant and completely symmetrical for a 3” peak to peak motion of the piston assembly, there is a constant relationship between applied coil current and generated force. The Thiele/Small parameters of the driver are more constant and less dependent on coil position. Because the voice coil is always surrounded by the same amount of metal and magnetic flux density, the electrical impedance is also independent of position and cannot produce distortions by this mechanism. Very good thermal coupling of the voice coil to the top plate, which always surrounds it, contributes to high power handling and low compression. Each driver can handle in excess of 1000 watts RMS! More importantly, a 12” driver with 3” of travel when used in the underhung manner can move more air and outperform two 18” woofers with 3/4” peak to peak travel as well as do it with much more visceral detail, effortlessness, and far less distortion. There is no comparison.

As a result of the research into the large signal behavior of high excursion transducers, distortion lowers and reliability improves. Since a transducer is a spring/mass system, a resonance frequency (Fs), a spring constant (Vas), and total damping (Qts) can describe a driver. When the suspension stiffness of a driver is increased (lower Vas), the Fs goes up, and Qts goes down; however, the system response of the driver in a small enclosure is virtually unchanged due to the dominance of the “stiffness” of the air in the enclosure, but again driver reliability and voice coil centering has been increased. All Fs, Qts, and Vas are controlled in the low frequency section of the Adrenaline active Brain 24dB active crossover.

This means that the free air resonance frequencies are not low, yet with the Qts correlation the finished speaker system is designed to go down below 15Hz with reliability and authority! The enclosures are massive 11/2 inch MDF panels with anti-symmetrical cross bracing. Thoroughly damped and sealed, these are indestructible fortresses. High-end connectors and oxygen free wire is used throughout. This is the most structurally devastating performing subwoofer you have ever felt, but has the visceral tightness associated with the finest mid-bass drivers known. Every Wisdom Audio Adrenaline Planar Line Source mates easily with these Low Frequency Regenerators because of their capability to perform below 15Hz and above 200Hz as well as their unrivaled quickness.