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Bose Acoustimass 5 series II Speaker System Review
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
Bose Acoustimass 5 series II Speaker System Review
Bose has now announced an improved version of this system, called the Acoustimass 5 Series II. The satellites have been restyled and actually reduced in size. Each measures only 6-3/8 inches high and consists of two roughly cubical enclosures about 3-1/8 inches square and 4-3/4 inches deep. The cubes can be independently rotated through almost 360 degrees, permitting the spatial properties of the speaker’s sound to be modified by reflecting some of its output off nearby walls. (Controlling the ratio of direct to reflected sound in the listening area has long been a Bose feature.)
Each sealed, molded-plastic cube contains a 2-1/2-inch driver that operates above approximately 200 Hz. The enclosures are filled with sound-absorbing material. Unlike the satellites in the original AM-5, the Series II satellites cannot be taken apart; the two cubes are permanently attached. Several types of brackets and stands are available for mounting the satellites in a variety of positions. The drivers are magnetically shielded so they can be placed close to a TV monitor without distorting the color.
Much of the special quality of the Acoustimass system derives from its unique bass module. In the original system, the module contained two 6-1/2-inch drivers whose front and rear outputs were loaded by separate cavities of different volumes. These cavities, resonant at frequencies about an octave apart, were ported to the room through a pair of 2-1/2-inch holes. The bass enclosure was equivalent to a bandpass filter, about one and a half octaves wide, whose steep high-frequency cutoff slope effectively prevented harmonics of the bass frequencies from being propagated into the room.
In the original AM-5, however, there was a slight gap between the low-frequency limit of the satellites and the high-frequency limit of the bass module, producing a measurable “hole” in the system’s frequency response in the vicinity of 200 Hz. With many types of program material the hole was not noticeable, but at times it could be heard as a somewhat disembodied low-bass presence.
This problem has been eliminated in the Series II. The upper limit of the bass module’s frequency response was extended while retaining (and even increasing) its very steep cutoff slope. The result is said to be a smooth, undetectable transition from the bass module to the satellite drivers together with an actual extension of the low-bass response.
The new bass module contains two 5-1/4-inch drivers (slightly smaller in diameter than the 6-1/2-inch drivers of the original AM-5) in a dual-cavity acoustic structure similar to the original design. But rather than each cavity’s having its own port to the room, both cavities are coupled to a third one, which in turn connects to the listening area through a molded plastic duct whose diameter flares smoothly from about 2-1/2 inches to about 4 inches at its exit from the box. The bass module’s frequency range is roughly 50 to 250 Hz.
The new Acoustimass bass module is approximately the same size as that of the original AM-5: 19-1/4 inches long, 14 inches high, and 7-1/2 inches wide. It can be placed almost anywhere, on any of its surfaces, as long as the vent is unobstructed (the opening should be at least 2 inches from other surfaces).
The Acoustimass 5 Series II is rated for operation with amplifiers able to drive loads of 4 to 8 ohms (the system is nominally 6 ohms) and with power ratings between 10 and 200 watts per channel. The Acoustimass bass module is available in a scratch-resistant black or white' satin finish, and the satellites are finished in a black or white polymer. Cables (about 18 feet long) are supplied for connecting the bass module to the satellites. The complete system, in its shipping carton, weighs 30 pounds. Price: $799.

























