PMC has announced the launch of the QB1 Active (QB1-A), large-scale, high-resolution main studio monitors with analog and digital (up to 192 kHz) inputs. It will be on display later this week at the 137th AES Convention in Los Angeles (booth 1628).
Designed for either soffit-mounted or free-standing use, each QB1-A incorporates the latest generation of PMC’s driver designs, Class-D amplification, Advanced Transmission Line (ATL) bass-loading technology, DSP control, and a quartet of 10-inch carbon fiber/Nomex piston bass drivers.
With a stated maximum SPL of 132 dB at one meter, the QB1-A can produce level, but not at the expense of accuracy or increased distortion. Each channel has a 4,825-watt Class-D amplifier (275 watts on the HF driver, 550 watts on the mid-range, and 4,000 watts on the four bass drivers), and the latest iteration of PMC’s ATL technology to deliver faithful low-frequency response down to 20 Hz.
The onboard DSP provides driver unit optimization, EQ and crossover networks, while the wired RJ45 desktop control provides user-friendly access to user EQ settings via its backlit display and jog wheel, with the ability to store up to four user setup presets.
The physical dimensions have been carefully considered—at 32.3 (h) x 43 (w) x 20.5 (d) inches (820 x 1092 x 520 millimeters), the QB1-A will retrofit into almost all existing studio soffits. Alternatively, its ATL design means that free-standing use has no impact on its smooth bass response.
The QB1-A has its roots in the observation by PMC’s design team that there were no large-scale active studio monitors on the market taking advantage of the latest developments in loudspeaker driver analysis and design and DSP-aided control. This starting point, coupled with PMC’s own extensive research into driver performance, using opto-acoustic laser inferometry at the UK’s National Physical Laboratory (NPL), aided and honed the design of the QB1-A.
“We saw that there was a gap at the high end of the market,” explains Oliver Thomas, R&D project manager at PMC. “In the main, the current products on the market don’t offer the flexibility of analog and digital inputs, and suffer from giving listeners an insufficient sense of resolution, compared to what can now be attained with good Class-D amp design and DSP-aided crossover management.”
The QB1-A makes up this ground, additionally employing recent advances in PMC’s transmission line design concept, as used in the company’s IB2 midfields and twotwo nearfields, and the aforementioned NPL analyses, to achieve more efficient, high-performance designs.
Extra bracing and damping inside the loudspeaker cabinet prevents noise and reduces resonance to insignificant levels beyond the limits of human audibility, while the newly introduced vertical strakes in the transmission line add further bracing and simultaneously reduce turbulence in the throughput airflow, making it laminar and contributing to the QB1-A’s faster, more dynamic sound.
Each loudspeaker employs three carefully integrated proprietary driver types. PMC’s soft-dome 34 mm and 75 mm drivers deal with the high frequencies and mid-range respectively, producing a natural, transparent sound with low distortion. Depending on client requirements regarding the height placement of the QB1-A, the HF driver may be placed above or below the MF driver as needed.
Four handmade, individually matched low-frequency drivers handle the bass, employing PMC’s proprietary “honeycomb” carbon-fiber/Nomex design in an extensively vented, cast-aluminum chassis. The flat-faced 10-inch piston driver in each bass unit helps ensure a near-instantaneous yet highly accurate transient response, while providing power required to drive the QB1-A’s heavily damped, high-compression transmission line.
The QB1-A’s final form, how it works, and its feature-set, are the result of over a year of practical testing by and feedback from leading producers and engineers on both sides of the Atlantic.
“Many engineers record with one set of monitors to create a sense of excitement while tracking, but then use another set for the low-level, intensely detailed business of mixing and mastering,” continues Thomas. “The QB1-A is designed for both kinds of work, offering faithful, non-fatiguing reproduction for a beautiful general listening experience or for recording, but with microscopic detail when you need it.”