Next in the M-Series is the M340, with four 41/2-inch (11.4 cm) woofers and a 41/2-inch mid-range driver. As with all the M-Series models, the M 340 incorporates a 1-inch EWB soft dome tweeter for Extended Wide Bandwidth performance. This sublime combination of four powerful bass drivers, one specialist midrange driver, and a uniquely ‘open’ tweeter is quite simply an audiophile’s heaven.
Unique EWB soft dome tweeter for Extended Wide Bandwidth
All floorstanding and bookshelf speakers incorporate the highly-acclaimed EWB soft dome dome tweeter. This completely opens up the mid-high to high frequency ranges to create an almost infinitely wide, sky-high sound stage. It’s an Extended Wide Bandwidth effect that is totally unique to Boston Acoustics.
The midrange used in the M 350 and M 340 has a unique visual identifier; four small rectangular “tabs” on the inside edge of the surround. These tabs add mass to the midrange to achieve a smoother frequency response at the top of the drivers’ operating range. This technique of using mass to smooth the response of the midrange has a specific design benefit. It eliminates the need to try and achieve the same sonic result by adding components to the crossover network. By smoothing out the midrange at the start with a mechanical solution, better consistency from unit-to-unit and superb sound quality and imaging in the critical upper midrange are maintained.
All m-series models are framed by a doublelayer side panel. Each of the two layers is 10 mm thick, and sandwiched between them is the Boston acoustics specially-developed SDG damping elastomer. This absorbs the internally generated vibration and ensures that the speaker cones remain autonomous. So absolutely nothing is added to the music, and absolutely nothing is taken away.
If the drivers are the heart, and the cabinet the body, the crossover is the soul of the speaker. The crossover is an electronic circuit that directs the appropriate sound range to each transducer and maintains the phase/timing accuracy between all of the transducers. All the parts in the crossover - resistors, capacitors, inductors – have an effect on the sound, and choosing the right parts will deliver the sound that the system is truly capable of. Special elements such as low loss film capacitors and low distortion laminated silicon steel core inductors have been used at all critical areas. On the M-Series location of the components relative to each other is optimize, to minimize electromagnetic interaction that could degrade the sound. On the M 350 and M 340 the entire woofer crossover network is located on a separate board to eliminate the potential of stray fields from the large inductors on the woofer network from cross-talking with components in mid/high frequency crossover network.
In addition to utilizing Lo-Q construction the M 350 and M 340 also utilize a separate internal chamber for the Mass-Loaded midrange. This acoustically isolates the midrange from the woofers inside the cabinet so they do not interfere with each other. Another benefit of the separate midrange chamber is that it doubles as a reinforcing brace near the top of the cabinet to add rigidity and reduce cabinet vibrations even further.
A common problem with conventional floor-standing speakers is the build-up of standing waves and their consequent interference. No such risk with the M-Series. By using four smaller bass drivers in the M 350 and M 340 (rather than two larger ones) dual oscillation and standing wave creation is simply not possible.
Laser-based vibration measuring has helped define the exact, optimised position for each cabinet’s internal bracing and mounting locks. This ensures that negative resonances are not just shifted to other frequencies but are totally minimised.
Frequency Range (±3dB):
45Hz – 30kHz
2,5 cm EWB Dome
4 x 11,4 cm
Nominal (Min) Impedance:
4 (3,2) ohms
Recommended Amplifier Power:
Dimensions (H x W x D):
102,6 x 22,4 x 29cm
High Gloss Black