Make and model Gradient Revolution MK IV
Frequency response 50-20000Hz +/-2dB, -6dB@30Hz, high frequency limit above 50kHz
Impedance 6 Ohm, minimum 5 Ohm
Radiation patterns Bass: dipole, midrange & treble: cardioid
Drivers 2×300mm long throw woofer, 176mm fibreglass midrange, coaxial aluminum dome 25mm
Sensitivity 87dB/2,83V/1m
Recommended amplifier power 50-250W
Crossover frequency 200Hz and 2800Hz
Features Bass level adjustment
Connections Two pairs of binding posts
Dimensions (WHD) 41 × 102 × 36cm
Weight 30kg
Room size Medium - Large
Suitable for home cinema Yes
Made in Finland

MER INFORMATION HÄR

The ideal loudspeaker

If we could have a magician conjure up the ideal loudspeaker from all the properties of current designs, the result could be as follows: A large dipole panel speaker which generates standing waves only in one direction. Because of the narrow dispersion it generates less unwanted room reflections. The resulting sound is clean, airy and non-boxy. Or a small two-way mini-monitor will give a very accurate soundstage and a wide listening area.

If we combine these good properties, and ignore the bad ones (narrow listening window of a panel speaker and the fact it cannot be positioned against the back wall, the weak bass response in mini-monitors, etc.) the result would be an ideal loudspeaker.
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Dipole bass

The bass part of Gradient Revolution loudspeaker consists of two 300mm custom made long throw woofers. They are assembled on an open baffle giving the low frequencies a "figure eight" or dipole radiation pattern similar to most panel loudspeakers. These two woofers operate from below 30Hz up to 200Hz.

An ordinary box speaker radiates in all directions at low frequencies. This has the unfortunate effect of generating standing waves in all dimensions (HxWxD). In the typical listening room, standing waves distort the sound at frequencies below 200Hz. Gradient Revolution does not excite standing waves between the floor and the ceiling, it can only generate them in the direction of the radiation pattern.

The woofer section of the Revolution can be rotated and directed in three different ways, to minimize undesirable standing waves in the listening area. This ability to "tune" out standing waves in the bass is unique. The result is a smooth articulate bass response which has correct musical pitch and dynamics.
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One point source
Frequencies over 200Hz are reproduced by a coincident driver assembly. A 170mm fiberglass cone handles frequencies up to 2800Hz. High frequencies from 2800Hz to over 20kHz are reproduced by a 25mm aluminum dome tweeter placed at the apex of the midrange cone. A point source is generally accepted as an ideal sound source for its excellent phase and amplitude response. This results in an extremely accurate, stable and three dimensional soundstage.

Coaxial cardioid

The midrange driver is mounted in an acoustic resistance enclosure giving the system a cardioid (heart shape) radiation pattern. The dome tweeter uses the cone of the midrange driver as a wave guide thereby providing the same cardioid pattern.

From 200Hz up, the speaker radiates sound mainly in the forward direction. The rear radiation is effectively damped by having a power ratio of 100 to 1. This minimizes any early reflections when the speaker is placed against the back wall.

Special attention has also been taken that the radiation patterns are consistent at all frequencies. The design of the speaker also minimizes sound reflections from the cabinet itself and nearby boundaries, thus negating the effects of diffraction.

The room influence to the sound remains very small, especially at mid and high frequencies giving the Revolution a very similar sound characteristic in many different rooms.

Flat energy response
The frequency response of the Revolution at the listening position is extremely flat; but this alone is not sufficient for Gradient. Every speaker radiates at least some sound in all directions. If the energy response of a loudspeaker has peaks and dips, the reverberant sound field will be uneven, coloring the music. Frequency response measured in all directions must be linear - as with the Revolution - in order to ensure linear energy response.

Crossover - the heart of the loudspeaker
Many of the superior sonic qualities of this speaker has been achieved by a properly designed crossover filter.

The electrical response of the filter alone has very little meaning - except in terms of power handling. More important are the acoustical responses of the drive unit/filter combinations and how they are tailored to work together in a multiway speaker system.

The acoustical slopes are 18 and 24dB/octave. The two-part crossover consists of selected components: air core inductors, wire wound resistors, and polyester film capacitors.

Many possibilities for room positioning

Gradient Revolution can be positioned in the room like a dipole speaker. In this case one or two meters from the rear wall is beneficial. Unlike panel speakers, the bass section of the Revolution can be directed in three different ways allowing for unique control over unwanted standing waves.

If a panel speaker is positioned near the rear wall the bass output will be attenuated strongly and the midrange will be colored by early reflections.

Gradient Revolution overcomes both of these problems. When positioned against the wall the bass section will be faced toward the adjacent wall. The bass can be attenuated by increasing the distance from the rear wall and fine tuned by rotating the speaker a few degrees.

Due to the radiation pattern at middle and high frequencies, unwanted early reflections are not created. The music will remain smooth and open with correct timbre as with conventional panel speaker positioning.

Also for home theatre

The Gradient Revolution loudspeakers are designed for the most demanding audio enthusiasts. However there are good reasons to use them as main loudspeakers in a home cinema system.

Colours and finishes to suit every taste
Gradient Revolution is designed and hand built in Finland with professional craftsmanship and very high quality materials. In addition to the variety of standard finishes, Gradient Revolution may be customized with a huge variety of options. In total over 20 different high quality fabrics and multiple real wood veneers allow personalized speakers for every taste.