It has been a long standing dream of many loudspeaker manufactures to design a system large enough to produce the full bandwidth of a music program. Such a system, however, needed to maintain the accuracy, transparency, and imaging precision of a physically smaller transducers. Most attempts to date have been relatively unsuccessful due to the complex parameters involved in the loudspeaker/room interface, and the seemingly contradictory requirements of bandwidth against sheer perceived accuracy of the loudspeaker in its environment.
Mission's engineers were intrigued by this dilemma. Research and development work cantered on drive unit and cabinet technology in order to resolve the conflicting requirements of low distortion and coloration, optimum dispersion characteristics, and high power handling.
Mission and Cyrus loudspeakers possess an unusually wide frequency bandwidth capability for their physical sizes. To bring the realism of live music into the home environment, the bandwidth must extend down to 20 Hz. This requirement has become even more relevant with the advent of digital recordings
In addition to the fundamental requirement of being able to physically move more air, Mission's research showed certain phase characteristics should be maintained to reduce the amount of phase distortion and perceived group delay in the listening room environment.
The ensure correct low frequency reproduction, it was necessary to use dedicated transducers for frequencies below 80 Hz. As well as obvious limitations in using passive cross-over networks at very low frequencies, no phase or group delay alignment is within engineering parameters in an affordable consumer home system. To eliminate these problems, Mission's engineers have implemented an active Low Frequency Alignment Unit (LFAU).
Two 6,5 inch mid-range units utilized in conjunction with the Super Elliptical Impedance Transformed high frequency unit produce the full bandwidth of 80 Hz to 20 kHz. The simple, high quality crossover network allows bi-wiring or bi-amping configurations. The lower two octaves of the frequency range are covered by two 8,25 inch drive units powered by a Cyrus based stereo amplifier and an active filter designed to integrate the low frequency and the mid-range units. This active network was designed to drive the LF units down to their free-air resonance frequency of 18 Hz, while compensating for the inter-driver phase shifts and group time delays. This system realizes a totally phase coherent, minimal group delay low frequency energy propagated in "time" with the full spectrum of the music program.
Controls are provided for further adjustment of this system to the particular room environment. These adjustments fine-tune the amplitude and roll-off points of the low frequency signal without upsetting the phase characteristic of the system.
The 767 is constructed throughout in 25 mm MDF. It is visco-elastically damped on all surfaces and braced at strategically sensitive points to produce a cabinet free of any coloration or measurable resonances. Modal analysis technique was utilized to develop a cabinet design with a fast energy dissipation, non-resonant enclosure.
The transducers used in the 767 are Mission's state-of-the-art. Drive units utilized in the top of the line Mission and Cyrus loudspeakers. The drive units are placed symmetrically in a vertical array to produce a dispersion characteristic designed to minimize floor and ceiling reflections (these two reflection sources are partly responsible for corruption of stereo imaging), while giving a frequency coherent wide lateral dispersion. This configuration was used successfully in the Argonauts for many years, and more recently in the Cyrus 782 loudspeaker. These drive units were developed through many years of research in materials and electromagnetic technologies, as well as ongoing refinements in construction and close tolerance engineering.
Specifications
Frequency Range: 20 Hz to 20 kHz
Frequency Response: 30 Hz - 20 kHz ±1,25 dB
Phase Response: 20 Hz to 20 kHz ±28 degrees
Sensitivity: 91 dB SPL (1 m/2,83 V)
Minimum Impedance: 8 Ω
Recommended Amplifier Power: 25 Watts to 250 Watts per channel
Maximum Sound Pressure Level: 114 dB SPL
Dimensions (H x W x D): 1400 x 270 x 430 mm (55" x 10" x 17")
Finish: Black Ash, Rosewood, Mahogany, Black Piano finish
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