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Equator Audio Research D8

Flagship Technology at a Reduced Price

One glance at Equator’s new D8 monitor is bound to make you linger. The vertically oriented monitor stations its coaxial drivers at the top of its cabinet, its large bass port positioned below. When testing these unusual speakers, I would soon discover it pays to think outside the box.

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The Equator D8 ($749/pair [factory-direct]) replaces the company’s Q8 monitor, leveraging the flagship model’s coaxial and DSP-based technology and substituting a tweeter for the Q8’s horn. During the transition between products, Equator moved to a factory-direct sales model, allowing the company to drop the D8’s price to one-quarter that of the Q8.

In coaxial designs, the high-frequency driver is nested inside the woofer, providing point-source propagation. But why use a tweeter instead of a horn for the highs? Horns are widely flared and typically larger than tweeters, so they tend to partially block the front of the woofer in a coax design. The typical sonic consequences are comb filtering, smeared imaging, a hole in the upper frequency response of the woofer (due to acoustic shadowing) and, for the tweeter, intermodulation distortion.

The D8 purportedly avoids all that. Its 1-inch silk-dome tweeter is ensconced inside a subtly flared circular ring that serves as a waveguide, offering little physical impediment to the surrounding 8-inch polypropylene woofer. Equator’s Zero-Point Reference technology uses internal DSP to time-align the two drivers, provide a steep 4th-order filter for their crossover, and match their output levels and voicing. (The D8 is sold in pairs after being calibrated at the factory for matched performance.) The time-alignment consists of a group-delay adjustment that is said to deliver phase-accurate midrange response in the 900Hz to 3kHz range.

The D8 is bi-amplified, a 60-watt amp powering the woofer and a 40W amp providing juice for the tweeter. An LED on the D8’s front face lights when power is applied. Drivers and amps reside in an all-wood (MDF) cabinet beveled on every edge: front, back and sides, both top and bottom. The bass-reflex port measures 2.5 inches; its exit out the cabinet’s front face makes it possible to place the D8 close to a wall without choking the monitor’s bass response. The cabinet measures 14x10x12 inches (HxWxD) and weighs 22 pounds.

There are no external heat sinks for the D8’s amps, but they do have protective circuitry that precludes overheating and short circuits. And the drivers are protected from clipping by a built-in limiter.

On the rear of the D8, you’ll find a three-position rotary switch marked “Boundary.” This control provides three alternate frequency-response curves, using built-in filters meant to compensate for various placements in a room. Position 3 is intended for freestanding placement; it creates a bell-shaped dip in response (roughly 2.5 dB and less than an octave wide) at 150 Hz and a boost of a few dB between 6.5 and 20 kHz. Position 2 applies filters to null Position 3’s bell-curve dip and high-frequency rise. Position 1 is meant for placement in front of a wall; its response is the same as Position 2’s except for additional filtering that rolls off the response 2.5 dB between 44 Hz and 1 kHz. Equator corralled award-winning engineers to devise these filter settings while referencing their hit mixes.

Also on the D8’s rear panel, you’ll find a stepped, rotary sensitivity control useful for precisely adjusting each monitor’s level; Equator calibrates this control at their factory using a port on the rear face that’s currently only sanctioned for the company’s use. The calibration port’s facility will eventually be expanded to allow users to recall additional frequency-response curves such as those for NS10M and Auratone monitors; user access to the port will be via a Wi-Fi dongle and a phone or tablet (Mac or PC).

Balanced XLR and TRS input connectors (the latter also accepts unbalanced lines), an IEC power receptacle and a power switch finish off the D8’s rear visage. The included 3-pin power cord is detachable and measures roughly six feet in length.

The D8’s frequency response is cited at 44 Hz to 20 kHz, ±3 dB. The monitor delivers up to 106dB SPL (measured at 1 meter and 1 kHz).

Listening Tests

For my listening tests, I set up a pair of D8s in vertical orientation (as recommended by Equator), placing them on Primacoustic Recoil Stabilizers. The front of my control room features an Acoustic Sciences Corporation Attack Wall, a modular arrangement of tube traps that tightens up imaging and impulse response at my mix position.

Listening to my mastered mixes, the boundary switch’s Position 2—which yields the flattest response of the three settings—sounded the best to my ears. I immediately noticed the D8’s excellent transient response and copious rendering of high-frequency detail. A strong, resonant peak between roughly 7 and 8 kHz, however, made male lead vocals sound strident and ringy on certain notes. Understated upper-bass and midrange response created a very open sound but a response that was nevertheless decidedly inaccurate.

Imaging was decent, except on elements of the mix attenuated by the trough in the D8’s midrange response. Violin sections, high-register electric guitar parts and BVs receded far into the background of every mix I listened to. Electric guitar parts played on lower frets and middle-register piano parts sounded thin, with understated fundamentals. And while I didn’t expect deep bass extension with an 8-inch woofer, the bass response above the 3dB-down point (44 Hz) sounded pillowy and understated. Obviously, the other Position settings (which boost highs or cut bass) couldn’t and didn’t help these numerous problems.

I also listened to a reject mix of mine, a Southern rock tune in which I had added too much upper bass and mixed the bass guitar too loud. On the D8s, the bass guitar sounded like it had a thin timbre and had been mixed at about the right volume. Had I mixed that track on the D8’s, I surely would’ve compensated for what I heard and ended up with an even boomier bottom end than what I had on my throwaway mix.

End of story? Nope. I decided to place the D8s on their sides, bass ports to the inside, to see if that would make a difference in their sound quality. It surely did. The improvement was dramatic: The bass and lower midrange bands sounded fuller and tighter. Imaging improved greatly, producing a rock-solid phantom center image and pinpoint localization for panned instruments.

Why the improvement? Placed on their sides, a lot more of the D8 cabinets’ surface areas were in contact with my Recoil Stabilizers, providing greater decoupling. And having the woofer resting less than 2 inches above the Recoil Stabilizers—versus suspended above a lot more enclosed air space, in vertical orientation—likely helped quell cabinet resonances and focus the bottom end. While the horizontal orientation didn’t help the sizzling high-frequency peak and the trough in the midrange response, the improved spectral balance overall made them sound far less objectionable.


The D8 requires horizontal orientation and acoustic decoupling for serviceable performance. The monitor’s strengths are excellent transient response and highly detailed reproduction of high frequencies. Its main shortcoming is its decidedly understated midrange response, which presents a challenge in setting correct levels for violin sections, electric guitars, piano and background vocals. In my opinion, the D8 is not flat enough to serve as a reliable reference for mixing.

But don’t take my word for it. Equator offers an unconditional, 60-day money-back guarantee. Take the D8 for a spin yourself, and see if you like it.

Mix contributing editor Michael Cooper is a recording, mix, mastering and post-production engineer and the owner of Michael Cooper Recording in Sisters, Ore.

Try This

When setting up a pair of D8s in horizontal orientation, make sure the drivers are placed to the outside. This will produce a wider stereo image and a slightly more centered bottom end.