The design of the EX66's midwoofers are a collaboration with UCLA's Dept of Materials Science

M-Audio recently sent over their EX66 nearfield monitors for us to TestDrive. Although the monitors have been around for about a year, the EX66's push M-Audio beyond their budget monitoring options and into a new price point for the concern. It's obvious that M-Audio wanted to make a statement with the EX66's. Not only do they incorporate provocative new technology and features, but they also utilize a dual woofer design that has lost favor with other manufacturers.

The one-inch, titanium-dome tweeter is located between the identical six inch, bass / mid-range drivers and is housed behind a shaped waveguide to maintain the vertical and horizontal dispersion angles at the crossover frequency point. This layout is sometimes referred to as a midwoofer-tweeter-midwoofer configuration, or MTM. The monitors are meant to be positioned vertically, not horizontally, with plenty of room needed behind the speakers due to the rear bass exhaust port. This poses some problems in studios that have decks with monitor seats built-in, or non adjustable stands, since the monitors are tall at 19 inches. M-Audio advises such positioning to narrow the sweet spot and to prevent the room's acoustics from significantly impeding the monitor's capabilities.

Features:

• MTM configuration
• Two 6" custom linear-piston woofers
• 1" titanium dome tweeter
• Bi-amplified with 200 watts PWM power per channel
• DSP-tuned cabinets and crossovers
• High-impedance analog inputs (XLR and TRS balanced)
• S/PDIF and AES/EBU digital input up to 24-bit/192kHz
• OptImage II high-frequency wave guide
• Acoustic Space control
• Soft limiter circuit to prevent clipping
• Calibrated volume control/input sensitivity control
• High-frequency roll-off/boost switch
• Mid-range presence switch (low-Q dip or peak)
• Low-cutoff switch (37Hz, 80Hz, 100Hz)
• MDF cabinet
• Internal adiabatic foam
• Dual flange rear-port design
• Magnetic shielding

Close-up of the M-Audio EX66's titanium tweeter

M-Audio enlisted the help of UCLA's Department of Materials Science for the design of the dual, linear-piston midwoofers. M-Audio's engineers wanted a ultra-light cone that was resistant to frequencey breakup issues. Inverting the driver's dust cap, and incorporating a Linkwitz-Riley crossover, give the EX66 a 2.56kHz crossover point with the intial breakup mode hitting at a claimed 6.5kHz. When the crossover point does occurs, M-Audio designed the Linkwitz-Riley to reduce the signal level by 30dB, diminishing the potential for distortion to reduce the overall sound quality.

With the EX66, M-Audio has introduced their own proprietary driver technology that utilzes an onboard digital signal processor instead of analog circuitry found in most monitors. This allows the concern to dial in the Infinite Impulse Response filters to combat problematic cabinent resonances that they feel are detrimental. However, the signal is forced through an Analog to Digital To Analog conversion, which proved problematic for many of the evaluators — more on this later.

Speaking of the cabinent, M-Audio went to great length to give the monitors a futuristic, yet functional appearance. The front-edges of the smooth, black enclosures are curved for reduced diffraction, and two glowing blue LEDs let you know the monitors are ready for action.

The EX66's are bi-amped with two individual 100-watt Pulse Width Modulation (PWM) power amps to power the 4-ohm midwoofers and 4-ohm tweeter, which is certainy more than the tweeter requires, but who's complaining.

The EX66 has a full compliment of connectivity, volume and tone shaping controls

The back of the monitors contain plenty of I/O options including balanced XLR and TRS analog inputs, a digital input (S/PDIF or AES-EBU), a volume knob, on/off switch and an Acoustic Space switch. The Acoustic Space can be set at either full (open space), half (close to a wall) and quarter (close to a corner) Frequency control is available with +2dB, flat or -2dB High-frequency options, mid-range (flat or +2 dB) boost, and three low-cut filter hits, 37, 80 or 100 Hz. These give you enough latitude to tackle any minor problems, and is a nice way to test consumer playback devices that may be "bass-challenged."

Although, we're wary of the monitors' converters due to the EX66's price point, the S/PDIF receiver can lock to an incoming clock of up to 216kHz, and the digital input can support a sample rate up 24-bit/192kHz, but is hard set at 24-bit/96kHz when the analog inputs are being utilized. Intelligent connectivity selectors specify left channel, right channel or stereo for the digital input.

The Sound

The EX66's high-end "had a bit of a bite" according to most of the evaluators, which some classified as "brassy" or "shrill." However, one tester found that the EX66's high-end prominence "helped the mixing process by forcing me not to over-hype the high-end." The "hit" is most likely due to the inherent nature of the titanium in the tweeter, which put them "right up front."

The dual mid-range woofers provided plenty of bass, which most of the testers had to spend "some time dialing in," but with the "plethora of bass management options" most testers were "pleased with the results." Once the bass was tuned, a couple of the testers noted the "excellent definition and detail of individual tracks" even with a "mid-range scoop."

Stereo imaging was somewhat of a issue for a couple of testers and a major problem for another. The narrow width, coupled with the height of the monitors are a question, since they are somewhat unwieldy for some studio environments. As stated before, for users who have limited adjustable stands or mixing on a desk, the monitor's height will be a hornets' nest. In addition, the speakers configuration narrows the stereo sweet spot, and moving your position will cause changes in the overal tonal quality. One tester attempted to rectify the problem by setting the monitors on their side, in the horizontal position, but "immediately ran into phasing problems" in his nearfield location.

Our testers mixed a wide variety of electronic music genres using the EX66's with varied results. On the plus side, even though the bass was somewhat "magnified" it did support an "extended spectrum" that ended up translating into a "defined low end." The same can be said about the upper frequencies. Even though many of the evaluators found high-end to be "promenently pushed," it translated into the final mix "not having the harshness that sometimes silk-domed tweeters trick you into delivering" for one tester.

On the minus side, none of the evaulators found the EX66's pleasurable for extended periods of mixing. "Although the separation of sounds is excellent for monitoring, the metallic quality of the upper mids would begin to grate on me after a while." The majority of testers found that it took a substantial amount of time to "settle into the EX66's" to achieve favorable results. The noise floor will obviously be a "nuisance for users who mix in very quiet environments." While one evaluator liked how the EX66's "kept my mixes honest" and might consider them as a "second pair," nobody would choose them as their primarily monitoring solution, even at their attractive price point.

Conclusion

The Future: First and foremost, if M-Audio decides to continue with this series, they needs to address the DSP noise issue. A monitor, even in this price range, cannot have a built-in white noise generator. The onboard DSP is a provocative concept, but without serious converters, it ends up being one step forward, two steps back. More mid-to-high range tuning may also help some users to eliminate some of the inbalance caused by the titanium tweeter's inherent snap.

The M-Audio EX66 Monitors retail for $699 each. Current Street Price.

More information on the M-Audio EX66 Monitors.