REVOLUTION WITH ACTIVE CROSSOVER
If you listen to the bass section of the Revolution alone you will be surprised to find how little information there really is under 200Hz. However the quality and quantity of this information affects strongly to the subjective listening experience. Too much bass will decrease the accuracy and deteriorate the feeling of space, too little makes the sound thin and tiring.
The real low frequency properties of a sound recording will be reproduced most convincingly by a dipole bass system giving the radiation pattern of eight. You can easily hear the minute tone nuances and follow the bass lines. When compared to the conventional closed box or bass reflex systems you will get the same sound pressure level at only one third of acoustic energy. Thus the room coloring effects are much less annoying and your neighbor will hear less of your bass lines.
Otherwise excellent system the dipole bass has one drawback, how to get high volume and how to reproduce the lowest notes. Gradient has solved these problems in the Active version. Hi-Fi enthusiasts have now unprecedented possibilities to fine tune the bass response both in quality and quantity.
POWER AMPLIFIERS ACCORDING TO YOUR TASTE
You can freely make your own choice of amplifiers to power the "Active" Revolution loudspeaker system. Signal coming from a sound source or a preamplifier is fed to the active crossover, and it is divided there into two parts to run two power amplifiers.
For the bass section it is recommended to use solid state amplifiers because of their low output resistance at low frequencies giving good control over the woofers. For the upper part of the spectrum (over 200 Hz) valve amplifiers will do as well.
ACTIVE DIPOLE CORRECTION
Due to the open construction of a dipole bass (without an enclosure at all) the frequency response will roll off at 6 dB per octave. The roll off point is higher than that of a closed or bassreflex box and needs equalization. In the standard version of the Revolution this is made in the passive crossover circuit. However the laws of physics and the actual size and price of components do not allow to extend the reproduction to the very lowest notes. This is easily done in the active crossover. The lower limit of the Active version is set to reach to 20 Hz, -2 dB.
The number of passive crossover components is minimized in the Active version. Only the crossover between mid and treble drivers is carried out by passive components. The woofers are directly connected to the power amplifier giving the best possible control over the cone excursion. Thanks to the active bass level control the sensitivity of the mid driver and tweeter can be fully utilized without attenuating them as in the passive version.
NEED FOR ADDITIONAL BASS UNITS
Experiences in various rooms have proved to be true, that the need for additional bass units seldom occurs. When listening at high sound pressure levels in large and well damped rooms extra bass units will give more headroom and reduce the distortion. Doubling the number of woofers will give 6 dB more headroom. It is possible to add any number of bass sections to the system.
FROM PASSIVE TO ACTIVE ONE
Every passive Revolution can be modified to the Active one at the Gradient service. Please, contact us for more information.
The crossover designed by Gradient and manufactured in Denmark is carried out following the best High End principles. The layout of parts and printed circuits made of high quality components are situated in a solid metal housing so that both external and internal magnetic and electrical interferences are eliminated. For instance the power supply is positioned far away from the small signal sections. The components used have passed the golden ear designer's tests, to mention only Burr Brown's operational amplifiers.
The crossover is equipped with both balanced XLR and unbalanced RCA connections to suite every audio system. Desired type is selected by a switch.
BASS LEVEL CONTROL
The level of bass can be adjusted continuously by a knob at the rear panel. According to the personal taste and listening room acoustics the bass is easy to adjust. Once found the correct balance, there is little need for further adjustments.
When playing warped LPs the cartridge tone arm system may give rise to high level subsonic frequencies which cause excessive cone excursion and take a lot of unnecessary power from the amplifier. Mono operation of bass channel will eliminate this.
The crossover includes a three position toggle switch to adjust the Q value.