Tower Speaker Reviews

Since launching the BP10 as its inaugural product in 1991, Definitive Technology has evolved its bipolar tower design through four generations. The 9000 series reflects the company’s latest thinking in engineering, components, and industrial design. According to Matt Lyons, senior VP of new product development, these speakers are new from the ground up, with only some design concepts (no parts) directly carried over from the 8000 series.

There are four towers in the new line, including the flagship BP9080x with top-mounted Dolby Atmos–enabled height drivers (also suitable for DTS:X), and the successively smaller BP9060, BP9040, and BP9020—the latter three are ready to accept the new plug-in A90 Atmos and DTS:X height module. Three new voice-matched center-channel speakers (CS9080, CS9060, CS9040) and two new bipolar surround speakers (SR9080, SR9040) complete the family. As with earlier BP models, all the towers and the two larger center-channel speakers feature powered woofer sections to enhance the system’s dynamic capabilities.

Though bipolar surround speakers are still readily found, Definitive appears to be alone now in producing bipolar mains. Well-executed bipole towers, which radiate direct sound from the front baffle and reflected sound off the back wall from rear-facing, in-phase drivers, project a wide, deep, and naturally reverberant soundfield compared with traditional direct radiators. The inherent compromise is some sacrifice (again, compared with direct-radiating loudspeakers) in the specificity of location and/or focus of individual instruments or voices within that soundfield. But advances made by Definitive Technology through the years are claimed to have minimized those effects while optimizing that huge, open soundstage that is a bipole’s calling card. Here are a few of the pertinent tech details that highlight the new BP9000 series.

Dolby Atmos/DTS-X integration. Definitive Technology is rightfully touting what Lyons calls “best-in-class integration” for Atmos and DTS:X object-based surround sound. Upfiring, Atmos-enabled height modules for placement above tower or bookshelf speakers are becoming commonplace now, but the BP9060, BP9040, and BP9020 are unusual in featuring a hidden compartment below a brushed aluminum top plate into which the new A90 height module directly plugs to achieve both a solid mechanical connection and an electrical link to a dedicated pair of binding posts on the speaker’s back panel. This avoids the ugly speaker-wire pigtail off the back of the module, and with just a fine line of aluminum trim separating the two pieces, creates a factory-look aesthetic match.

Enhanced Forward-Focused bipolar array. Beginning with the BP8000 series, Definitive Technology introduced a “Forward-Focused” topology that reduced the output of the rear-facing drivers by 6 dB compared with the front drivers, which is said to improve overall image focus and precision while maintaining the wide and deep soundstage for which bipoles are known. Redesigned crossovers in the 9000 series are said to have further improved on those results, as has the addition of Intelligent Bass Control (see below).

New Class D amps with Intelligent Bass Control. The amps driving the woofer section in all the towers and powered center speakers are now DSP controlled and employ “Intelligent Bass Control” to adjust woofer output. In essence, the system is designed to allow boosting of the bottom two octaves without altering the bass-to-midbass blending and crossover point. Lyons says this greatly helps to maintain midrange clarity and avoid low-end chestiness as the bass cranks up, which contributes to the aforementioned improvement in image focus. (RMS amplifier output ratings are as follows: BP9080x, 455 watts; BP9060 and BP9040, 300 watts; BP9020, 150 watts; CS9080, 300 watts; CS9060, 150 watts.)

Late-generation drivers. Incremental improvements have been made to Definitive Technology’s previously introduced BDSS (balanced double surround system) midrange driver design, which employs a dual suspension system with a flexible surround at both the outer perimeter of the polypropylene cone and, unusually, on the inside where it meets the voice coil to allow for longer and more linear cone excursion. The aluminum dome tweeters have been evolved to further smooth out frequency response. Driver size complements from model to model were mostly maintained compared with the 8000 series, with the notable exception of a bumping of the midrange drivers in the BP9040 to 4.5-inch from 3.5-inch in the BP8040ST, made possible by a wider cabinet. The improvement in dynamics is claimed to make that particular $899 (each) model an exceptionally strong value in the line. The CS9040 and CS9080 center speakers also saw driver or passive radiator upgrades from their predecessors.

Redesigned cabinet. The new cabinet design is meant to further reduce diffraction effects off the front baffle, and a new, stiffer grille sock material vibrates less while still providing the required acoustic transparency.

Industrial design. Much attention has been paid to aesthetics in the new line. An attractive aluminum base adds vibrational rigidity and improves stability compared with the outriggers on the 8000 series, and can be outfitted with gliders or spikes. The aluminum top plate for the height module compartment lends a high-tech accent and hides an attractive interior that’s seen only during module installation. A glowing D logo at the bottom of each tower acts as a pilot lamp, coming on bright when the speaker is first powered up but then fading down to the user’s preselected brightness (or to full off).—Rob Sabin