The “SRM” Stands for Sound Reinforcement Monitor
Over a decade ago, Greg Mackie and a dedicated team of engineers set out to create a portable loudspeaker that could deliver studio monitor sound quality. Unlike a relatively small, acoustically controlled studio where the “sweet spot” is well defined, live venues vary greatly, and most are far from acoustically balanced. Despite the challenges, after two years of extensive research and development, the first Sound Reinforcement Monitor was born—a loudspeaker that truly lived up to its name. The SRM450v2 continues the SRM450’s tradition of studio monitor sound quality—and trumps it—to deliver sound that makes any venue seem like a well-tuned studio.

We switched from the original SRM’s Class A/B amps to Class-D amps because Class D offers significant benefits over traditional topologies such as:

• High Efficiency, Less Heat: Traditional amps produce 50 percent amplification and 50 percent heat. Class D amplification is greater than 90 percent efficient, with 10 percent (or less) heat. That’s cool!

• Compact Architecture: Because they’re so efficient, Class D amps don’t need big old heat sinks, so they can fit in tighter spaces. Smaller amps = smaller loudspeaker.

• Lighten your Load: Without massive heat sinks, and combined with their switching power supply, these digital amps weigh in at about half as much as a traditional linear transformer and traditional amp design. 

Well if Class D amps are so great, why didn’t we just stop there? Because they have one pitfall—poor distortion characteristics, especially on transients. But our Fast Recovery circuitry takes care of that. It minimizes amp latching, thereby eliminating that pesky distortion problem.

So what the heck is latching? Essentially, it’s when the amp gets “stuck” in clipping mode. Amplifiers have the unreasonable task of taking line level signals of about one volt and amplifying them by nearly 300 times their starting point. Any type of quick transient, such as a kick drum or snare hit, puts extra pressure on an amp to deliver quickly. The latching effect is most prominent when the amp is near its clipping point, and we know this is where lots of folks like to keep their levels—pushed to the limit. Mackie’s Fast Recovery circuitry helps the amp to avoid latching and recover quickly, leaving your sound distortion free and clean as a whistle.

Legendary Active Electronics 
In a passive loudspeaker setup, an external amplifier is connected to a passive crossover inside the speaker, which distributes frequencies to the transducers. Because power amps and transducers vary widely in sound and quality, trying to match the right power amp with the right speaker can be challenging, especially if you’re not a professional acoustic technician—or rolling in cash so you can hire one. Our proven Active design does all the work for you. With our SRM450v2, you get a complete loudspeaker system, with complex electronics and carefully chosen components, all precisely tuned and tweaked to work together. The result is a loudspeaker with phenomenal sound quality and power, that’s completely plug-and-play—no EQ needed.

Phase-Accurate Electronic Crossovers – Featuring separate Linkwitz-Reilly 24dB-per-octave crossover circuits for the LF woofer and HF compression driver, our electronic crossover circuitry effectively splits input signal frequencies into highs and lows for the transducers, and eliminates unwanted phasing issues. As a result, you get optimum imaging, depth of field and definition. A closed system like an SRM350v2, where the design engineers know what amplifier and transducer will be used, makes this possible. In powered or passive setups, keeping signal in phase is difficult to achieve—nearly impossible if you don’t have oodles of cash to spend. And when the signal is not in phase, you get inconsistent sound with lots of muddy artifacts that change the listening experience as you walk around the room.

Transducer Time Correction – Our Time Correction technology effectively times the arrival of electrical impulses to each transducer, to ensure both highs and lows arrive at the listeners’ ears simultaneously. In a typical 2-way loudspeaker, the compression driver that reproduces mid- and high frequencies is located deep inside the speaker enclosure. Once sound is produced, it must travel from the compression driver through the horn to the listener. The LF driver (i.e. the "woofer") is much closer to the front of the speaker.    Left unchecked, bass arrives at listeners’ ears sooner than treble. Our sophisticated electronics inside the SRM350v2 give the compression driver a “head start” over the LF transducer, so the differences in sound generation speed are accounted for. They allow precise alignment among the system components, without any audio signal degradation whatsoever.

Final Tuning Equalization – The last tool in the Mackie Active electronics belt are final tuning EQ filters.  Once time alignment and phase correction are controlled and optimized, our engineering gurus at EAW use very precise, yet mild, built-in EQ filters to do the final tuning of all Mackie Active loudspeakers. They have years of experience tuning not only individual multi-way loudspeakers, but also complex loudspeaker systems such as line arrays, so you know the right ears are on the job. And a little goes a long way—thanks to their magic touch, you get unparalleled clarity thru the mids, brilliance in the highs, ample punch in the low end, and the flattest, most accurate frequency response available.

Built-in Protection Circuitry for Long Life
We know our Active loudspeakers are pushed hard—often to, or beyond, the limit. That’s why we have reliable protection circuitry built in to every one. The SRM450v2 employs a built-in limiter for less distortion at peak levels, and an automatic sliding high pass filter to give you that little bit extra volume when the crowd demands more. And thanks to the advanced technology of its power supply and Class-D amp topology, the SRM450v2 is greater than 90 percent efficient—more of the power from your outlet goes straight to the transducer, without the power supply and amp giving off loads of heat. Less heat means better performance, and longer life.

Versatile, Portable, Tough—And They Look Good, Too
When designing the SRM450v2, we considered every angle. From every angle is just how you can position it, too—pole-mount it from the bottom, fly it vertically or horizontally via its integrated M10 mounting points, or use it as a wedge monitor. With all this flexibility, it’s the most versatile portable Active loudspeaker around. And now moving it into place is easier than ever. Weighing in at about 40 pounds—11 pounds lighter than the original SRM450—you’ll have plenty of strength left over to play after loading in. Plus, the SRM450v2 retains its rugged, Mackie “built-like-a-tank” durability, thanks to the polypropylene cabinet—now in a tasty hue of Midnight Blue. So not only do you get a portable loudspeaker that sounds phenomenal, you get one that’s tough and portable for the road, and handsome enough for the show.