The MM‑4XPD directional miniature self‑powered loudspeaker with IntelligentDC™ technology was specifically designed for high‑quality distributed systems in reverberant spaces. The directional polar pattern of the MM‑4XPD, especially at low frequencies, significantly reduces room excitation and increases intelligibility. Its flexible and easy‑to‑configure mounting options, as well as its ability to effortlessly reproduce both speech and music, make the MM‑4XPD an excellent choice for large distributed systems, theatrical presentations, museums, and small portable systems for corporate audio‑visual, where intelligibility is critical.
The MM‑4XPD meets the same exceptional performance standards as the MM‑4XP with the added advantage of a hypercardioid coverage pattern. Patent‑pending technology yields a high degree of attenuation between the front and rear of the loudspeaker, achieving a directional polar response using passive acoustical techniques. Even at low frequencies, the breakthrough technology yields 10 dB of attenuation at the rear of the loudspeaker while retaining directional dispersion at high frequencies.
The MM‑4XPD employs a single‑driver design, avoiding the complexity and cost incurred by directional techniques implemented with two drivers that would require additional amplification and signal processing. Housed in a compact aluminum enclosure, the single 4‑inch cone transducer, designed and manufactured at Meyer Sound’s Berkeley, California factory, delivers an impressive linear peak SPL of 111.5 dB with crest factor >16.5 dB3, and a wide operating frequency range of 120 Hz to 18 kHz with very low distortion. The MM‑4XPD exhibits the same high intelligibility and flat frequency and phase responses for which Meyer Sound loudspeakers are known. Peak and rms limiters regulate loudspeaker temperature and excursion.
The MM‑4XPD receives power and balanced audio from a SwitchCraft® EN3 5‑pin male input connector on its rear panel. The MM‑4XPD’s amplifier and signal‑processing circuits were designed to store DC power and tolerate voltage drops, thereby accommodating light‑gauge cables and long cable runs.
MM‑4XPD loudspeakers require a Meyer Sound external power supply. The MPS‑488HP IntelligentDC power supply is ideal for larger installations with multiple loudspeakers; the single‑space rack‑mount unit distributes DC power and balanced audio to up to eight MM‑4XP loudspeakers or other compatible Meyer Sound low‑voltage loudspeakers. Another option is the 1RU, 1/2 width rack‑mount MPS‑482HP IntelligentDC power supply that offers two channels of audio and DC power.
Meyer Sound’s RMS™ remote monitoring system, which enables comprehensive monitoring of system parameters from a Mac® or Windows®‑based computer, is available as an option for the MPS‑488HP.
Both Meyer Sound power supplies can deliver DC power to MM‑4XPD loudspeakers at cable lengths up to 300 feet with just 1 dB of loss in peak SPL when using 18 AWG wire. The use of composite multiconductor cables (such as Belden® 1502 or equivalent) allows a single cable to carry both DC power and audio to the MM‑4XPD. Longer cable lengths are possible for moderate applications that do not drive the loudspeakers to maximum output, or for installations with heavier gauge wires. Powering the MM‑4XPD from a unipolar external power source reduces induced noise significantly and eliminates the need for wiring conduits. For information about, and specifications for, the Meyer Sound power supplies, see meyersound.com/product/mps.
The MM‑4XPD’s extruded aluminum enclosure acts as a heat sink to dissipate heat from the driver’s voice coil. The enclosure is available in a standard black anodized finish with a perforated steel grille. The enclosure can also be custom painted to match specific color schemes. The optional MUB‑MM4XPD U‑bracket facilitates mounting of the loudspeaker on walls and ceilings at adjustable angles.
