Boston A200 loudspeakers

The A200 is a high performance three-way loudspeaker system designed for optimum reproduction of music under actual home listening condition. Its design takes particular advantage of recent research about the colorations which can be caused by off-axis sound radiation when it reflects off parts of the speaker, is diffracted at cabinet edges, and is strongly reflected off floor and wall surfaces near the speaker.

These reflections have been controlled in the A200 by the shape of the cabinet and careful attention to the placement of the drivers, yielding a speaker system which exhibits a remarkably uniform and accurate tonal balance, exceptionally good stereo imaging, and relatively high efficiency.

The 10" woofer is mounted near the floor and the shallow cabinet permits convenient placement near a wall behind it. Consequently the woofer behaves acoustically as if it were flush-mounted at the floor-wall intersection, radiating uniformly into the 90-degree solid angle formed by that intersection with all reflections remaining in-phase with the woofer's direct output, preserving its smooth response and raising its efficiency.

The 4-1/2" midrange and 1" soft dome tweeter are positioned near  ear level for realistic musical imaging. They are flush-mounted in an unusually large and smooth front-panel area, so that the nearest cabinet edge or reflecting object is more than a half-wavelength away at any frequency in their operating range.  Consequently the drivers radiate essentially a hemispheric wave front, and the control of early reflections permits their smooth response to be heard to full advantage.

The infinite plane enclosure

The A200's enclosure design isn't a cosmetic "sales feature". It is calculated specifically to restrict the amount of sound than can reach the rear wall and floor, especially at the crucial midrange frequencies that determine a speaker's tonal character and imaging capability.

The A200's unusually large and smooth front panel makes the midrange and high frequency drivers behave as if they are mounted into an infinitely large plane extending beyond the baffle. As a result, they acoustically "see" only the hemispheric space in front of the cabinet, eliminating the early reflections that can color their sound and blur the stereo imaging.

Dealing with bass frequencies and their very long wavelengths required a different solution. By mounting the woofer close to the floor, floor reflections remain in phase, reinforcing the woofer's output and preserving its smooth response.

Another benefit of the A200's tall, slim cabinet is the opportunity to mount the midrange and tweeter near ear level to enhance the sonic perspective. Mid and high frequency information emanates at the proper height in space, eliminating the "highs-at-knee-level" phenomenon of typical cabinet shapes.

Specifications:

Drivers:

Low-frequencies  :  10" (250 mm) acoustic suspension woofer

Mid-frequencies :  4-1/2" (120 mm) midrange with ferrofluid

High-frequencies ;  1" (25 mm) soft dome tweeter with ferrofluid

Crossover Frequencies:  450 Hz and 3000 Hz

Sensitivity:  1 watt produces 90 dB at 1 meter

Impedance:  8 Ω nominal

Low Frequency Response "  -3 dB at 36 Hz

Driver Fuses:

Tweeter :  1,5 A

Midrange :  2 A

Dimensions (H x W x D):  1040 x 530 x 160 mm (41" x 21" x 6-3/8")

Weight:  27 kg (58 lbs)

Boston A150 loudspeakers

The new model A150 offers performance similar to our larger, more expensive A200 in a more compact, less expensive enclosure.

The three-way A150 employs a 10-inch acoustic suspension woofer, a 4-1/2" midrange with ferrofluid, and a 1-inch soft dome tweeter with ferrofluid in a 30-1/2" (high) x 16-1/2" (wide) x 8" (deep) cabinet finished in furniture-grade oak veneer.

A 1-1/2-inch black pedestal base is supplied for floor placement.

The tall, slim cabinet together with careful driver placement minimize out of phase reflections from nearby room surfaces (the flor and the wall behind the speaker) for exceptionally smooth response and precise stereo imaging.

Specifications:

Frequency Response:  36 Hz - 25,000 Hz ±3 dB

Crossover Frequencies:  550 Hz and 3000 Hz

Impedance:  8 Ω nominal

Sensitivity:  90 dB at 1 meter with 1 watt input

Dimensions (W x W x D):  32" x 16-1/2" x 8"

Boston Acoustic A70

In a stereo system, the loudspeakers are the key components. Because they are devices that you hear, the system can never be better than they are, if your speakers are less than excellent, accuracy will suffer, and so can your enjoyment.

The Boston Acoustic A70 is a highly accurate reproducer of music. In addition to faithfully recreating the full audible range of music, the A70 can image more accurately than most speakers offered at any price.

An accurate stereo image increases realism.

When you listen to a stereo system, close your eyes, and find out whether your mind's eye can "see" where each instrument is located.

Boston Acoustic speakers are well-known for their ability to recreate an accurate stereo image that increases realism and enjoyment. The slim profile of the A70 not only makes it easier for you to place the speaker unobtrusively in a room; more important from a music lover's point of view, the dimensions of the cabinet minimize unwanted sounds that would ordinarily muddy the stereo picture. The result is a crisp focused image.

Another characteristic that contributes to good imaging is a tweeter that's matched to the woofer in terms of its radiation pattern. A limitation of ordinary tweetere is that they radiate sound forward in a tight pattern, like a flash-light radiates light. In contrast, all woofers radiate over a broad area,like a table lamp. The tweeter incorporated in the A70 radiates in a very broad pattern, making the woofer and tweeter a well-matched team. Hence, the stereo image is clear and distinct.

The best combination of range and accuracy inn its price class.

The A70 maintaining the correct proportion while reaching farther into the bass than any other speaker in its price class. The quality of the drivers is largely responsible. The tweeter is the same one we use in most expensive nodel. The woofer is a helfty 8-inch driver designed to providethe best combinationof deep bass and efficiency. It reproduces the lowest notes in music - notes that most listeners never heat, except in live performances.

A room-size sound from as little as 15 watts

With very little  power, the sound of two A70 speakers will fill an average size room to overfloving. The A70 performs well with a receiver or amplifier as low as 15 watts per channel. Its efficiency means you can spend less money on your receiver or amplifier, and get excellent performance.

Specifications:

Frequency Response:  40 - 25,000 Hz ±3 dB

Impedance:  6 ohms nominal

Sensitivity:  1 watt produces 90 dB at 1 meter

Drivers:

Low-Frequency :  200 mm (8") long throw woofer with focused gap magnet assembly for low distortion

High-Frequency :  25 mm (1") soft dome tweeter with ferrofluid cooling

Crossover Frequency:   2000 Hz

Recommended Amplifier Power:  15 to 75 watts per channel

Power Rating:  75 watts nominal;  150 watts peak

Internal Volume:  28 liters

Cabinet Finish:  wood grain vinyl finish over non-resonant particle board

Dimensiond (W x H x D):  356 x  610 x 203 mm (14" x 24" x 8")

Weight:  11,8 kg (26 lbs)

Boston Acoustic A60

A small speaker system that produces a clean, undistorted sound image comparable to much larger, more expensive speakers. In addition, the A60 offers the same imaging capability, efficiency, and ease of placement as our more expensive loudspeaker system.

High speaker efficiency means low amplifier cost.

The Boston Acoustic A60 is a highly achieve full volume. An amplifier or receiver rated as low as 10 watts is sufficient (though the speaker can handle as much as 60 watts). This efficiency means you can spend less money on your receiver or amplifier and get excellent performance.

More placement options than other speakers, large or small.

Because the A60 is small and lightweight, it fits easily and unobtrusively into any room. And because it radiates sound in a broader pattern than most loudspeaker systems - like a table lamp instead of a spotlight - it performs well in a veriety of positions, giving you many placement options.

An accurate stereo image increases realism.

Boston Acoustic speakers are well-known for their ability to recreate an accurate stereo image that increases realism and enjoyment. The dimension of the cabinet minimize unwanted sounds that would ordinarily muddy the stereo picture. The result is a crisp, focused image.

Another characteristic that contributes to good imaging is a tweeter that's matched to the woofer in terms of its radiation pattern. A limitation of ordinary tweeters is that they radiate sound forward in a tight pattern, like a flashlight radiates light. In contrast, all woofers radiate over  a broad area, like a table lamp. The tweeter incorporated in the A60 radiates in a very broad pattern, making the woofer and tweeter a well-matched team.

The best combination of range and accuracy in its price class.

It;s not just how high and how low a speaker can go, but how far it can reach into the bass and treble regions while maintaining the correct proportion of high and lows.. The A60 maintains this correct proportion while reaching as high into the treble and as deep into the bass as any speaker in its class.

The A60's woofer uses a specially formulated cone material to eliminate frequency response irregularities at the top end of its operating range. The 1-1/2" tweeter has unusually wide dispersion for a diaphragm its size, due in large part to its elastometric edge termination. Its voice coil is bathed in ferrofluid to improve power handling.

Among the refinements in the A60 are a single-pole (6 dB/oct) network for uniform blending of the drivers in the crossover region and a smooth, easy-to-drive impedance. The grille panel has a 30-degree bevel around its inner perimeter that virtually eliminates early reflections (diffraction) that can blur the stereo image.

Specifications:

Drivers:

High-frequency :  1-1/2" tweeter with ferrofluid cooling

Low-frequency :  8" long throw woofer

Frequency Response:  55 Hz - 22,000 Hz  ±3 dB

Crossover Frequency:  6 dB/octave at 3000 Hz

Impedance: 8 Ω nominal, 6 Ω minimum

Sensitivity (at 1 watt/m input):  90 dB

Recommended Amplifier Power:  10 to 60 watts per channel

Dimensions (H x W x D):  457 x 292 x 197 mm (18" x 11-1/2" x 7-3/4")

Weight:  7,3 kg (16 lbs)

Cabinet Finish:  wood grain vinyl finish over non-resonant particle board

Boston Acoustics A40 (1985)

In our continuing effort to lower cost of high performance stereo systems, we are pleased to announce the introduction of the Bosto Acoustics A40. Housed in a 343x210x197 mm deep wood-grained vinyl enclosure, the A40 uses a newly-designed 170 mm woofer manufactured by Boston Acoustics and a ferrofluid-damped 19 mm tweeter.

Tha A40 is ideal for moderate-sized rooms, dorms, dens, bedrooms, you name it - either as a primary or extension speaker. its imaging capability is unique in its price range, and its dispersion is exceptional. This remarkable performance makes the A40 a stiff competitor to anything at or near its price, and its compact size permits a wide range of placement options.

Specification

Drivers:

6½" (170 mm) long throw woofer,

¾" (19 mm) ferrofluid cooling tweeter

Frequency response: 68 - 20,000 Hz, ±3 dB

Sensitivity: 88,5 dB at 1 watt/1 m

Impedance: 8Ω (nominal)

Crossover frequency: 3500 Hz

Recommended power : 5 to40 watts

Dimension: 343 x 210 x 197 mm (13½" x 8¼" x 7¾")

Weight: 4,1 kg (9 lbs)

Cabinet finish: wood grain vinyl over non resonant particle board