Oct 21, 2004 3:54 PM, By George Petersen

BI-AMPLIFIED STUDIO MONITOR

Founded 12 years ago, KRK has won wide acceptance in the music recording and post communities for its near-field and main studio monitors. I’ve been testing the Exposé model E-8 ($3,995/pair), which tip the scales at 61 pounds each. Weight provides, perhaps, the first clue as to the E-8’s primary application: as a mid-field monitor in a medium to large listening space.

The Exposé range comprises a series of powered two-way monitors with 7- or 8-inch LF drivers (hence the model numbers E-7 or E-8) and 1-inch inverted-dome Kevlar tweeters. The woofers feature two-ply sandwiched Kevlar cones. Each driver is powered by a 140-watt internal amplifier routed through an active crossover at 1.7 kHz. The input on each E-8 is a balanced XLR; recessed controls include an input sensitivity pot and a switch for rolling off the high end (up to -1.5 dB max) in 0.5dB steps. Also on the rear panel is a standard IEC removable AC socket and power switch.

The enclosure itself is a work of art: The tapered hexagonal shape and finned ports on either side of the drivers give it a futuristic look, and the whole is beautifully finished in high-gloss polyurethane. More important, the cabinet’s hexagonal footprint substantially reduces the number of parallel surfaces; according to KRK, the E-8’s tapered-polygon rear concentrates sound at low frequencies to optimize LF response. Grilles (which nobody uses anyway) are not provided, and the cabinet corners are rounded to reduce diffraction effects.

Based on the E-8s’ substantial 122-pound/pair heft, I resisted the urge to test the structural integrity of my console’s meter bridge and instead opted for some sturdy monitor stands. I plugged the monitors in, powered them up and was ready for some listening. The onboard amps are quite clean; on several occasions, I forgot to power them down after a session because there was no amp hiss to remind me. With this in mind, perhaps KRK should add a front panel power LED because when I turned the console on the next day, a familiar “snap” reminded me of the old lesson: Amps are last-on/first-off devices.

If there is any single word that describes the E-8’s sound, it is big. The speakers are easily capable of peaks in the 115dB range. Those who really like it loud may appreciate the E-8’s onboard thermal shut off and current limiting circuits, which offer protection for the speakers, if not your ears. However, even under more sane listening conditions, the sheer amount of bass the E-8s produce can overwhelm a smaller space. (In such cases, the smaller KRK E-7 speaker would be more appropriate.)

The LF response is smooth and tight, with a 3dB down point of 47 Hz, although usable bass response extends well below that figure. And like it or not, the E-8s paint an extremely realistic picture of everything in the LF spectrum, whether it’s air-conditioning noise, distant subway rumble or any one of a zillion LF artifacts that creep into high-resolution recording systems. In such cases, other speakers may lull the listener into thinking these gremlins don’t exist, but the E-8’s flat true bass response does an excellent job of warning the engineer of potential problems so they can be corrected before an audio creation goes on-air, onscreen or onto store shelves.

The MF response has a slightly forward sound, but this never presented a problem. Interestingly enough, during my tests, I found that blocking the slotted port yielded a somewhat smoother midrange sound at the expense of a decibel or two of bass response. Whether you want to try this with your E-8s is up to you, but sometimes it’s nice to have options. But just as they are, the overall sound of the speakers is open, offering excellent imaging, tight transient response and a well-balanced sound stage with a nice sense of depth and placement of individual elements in the mix. The top-end HF response rolls off somewhat, but the net result is that the E-8s are extremely nonfatiguing, even after extended listening sessions.

In addition, the monitors generate an extremely wide sweet spot, which is ideally suited for larger consoles or situations where several people (such as an engineer, producer and artist) are listening from behind the board at the same time. More important, the sweet spot is wide enough so that when you reach to the side for an outboard device or all the way across a board—say, to EQ a kick drum on channel 1—the E-8’s sound remains consistent.

As with nearly all studio monitors, the E-8s require a short period of familiarization. However, once I was accustomed to their “sound,” I found that my mixes translated accurately to audio systems of every kind, from boom boxes and car stereos to mid- and high-priced home systems. I work on a number of systems (including Meyer HD-1s, Focus Audio Model 68s and a reliable—but now vintage—pair of KRK 703s), and when I’m using an unfamiliar set of monitors, I generally find that determining the correct amount of bass is the most difficult part of balancing a mix. With the E-8s, the amount of bass in the mix was always spot-on, and after a day of listening to the E-8s, I was confident that my mixes would translate to just about anything. And isn’t that what mixing is all about?

KRK Systems Inc., www.krksys.com.

Lab Analysis: KRK E-8 Monitors
By Jack Hidley

Physical Characteristics
The KRK E-8 has a unique cabinet design. Viewed from the top, the cabinet has a hexagonal shape. This reduces the number of parallel internal surfaces, which, in turn, reduces the intensity of the internal standing waves. All surfaces of the cabinet are 1-inch MDF with large 1-inch radii at the joints. The large radii will reduce baffle diffraction and, as a result, smooth the frequency response. The cabinet is very rigid and well damped. The exterior finish is a very hard, shiny-gray material, perhaps a polyester or epoxy resin. There are no provisions for grilles. The drivers are flush-mounted into the baffle with threaded inserts and machine screws.

The woofer appears to be a popular Focal model. It has a straight-sided two-layer Kevlar cone with a rubber surround. The voice coil leads are dressed tangentially to the cone, allowing very high excursions before they strike the cone. The woofer is not shielded, although the frame is cast-aluminum, which will reduce the effects of stray magnetic fields somewhat. The motor structure (pole piece) is vented to help cool the voice coil and reduce power compression.

The inverted-dome Kevlar tweeter with foam surround is similar to a popular Focal model. The voice coil is underhung for increased linearity and drives the dome nodally to decrease the effect of breakup modes. The magnetic structure has a large ferrite magnet and, like the woofer, is not shielded.

There are two separate amplifiers in the E8. One is housed in each of the panels on either side of the front baffle. This leaves the heat sinks exposed, resulting in a high-tech appearance. The amplifiers are very similar to each other, delivering 170 watts to the woofer and 120 watts to the tweeter. Each amplifier has its own filter capacitors, while the toroidal transformer and crossover circuitry are housed in a sub-enclosure in the rear of the cabinet. Discrete circuitry is used for both amplifiers. The rear panel has a single XLR balanced input, a continuously variable input sensitivity control, a DIP switch to adjust the tweeter level and a socket for an IEC power cord. The crossover is at 1.6 kHz with slopes of 24 dB/octave. There is a small amount of equalization in the woofer and tweeter circuits to flatten the response.

Acoustic Characteristics
The E-8’s most prominent characteristic is its very wide dispersion. This is achieved by combination of a low 1.6kHz crossover and the use of an inverted-dome tweeter. At -30° off-axis, most monitors are down 2 to 5 dB in the midrange and high end. By contrast, the 0° and -30° curves of the E-8 look almost identical to each other. This wide dispersion will give a very consistent tonal character, regardless of the listening distance or the room reflectivity. However, some room treatment may be required to control early reflections.

Over most of the frequency range, the response is fairly smooth. There is a 2 to 3dB increase in output between 500 Hz and 2 kHz, which makes the soundstage very large and a little forward. The spectral contamination levels were -40 dB down from the signal tones, which is average performance. The impulse response is typical of a two-way speaker without time alignment. A small amount of ringing is visible on the tail of the impulse.

With 290 watts of amplifier power, high-slope crossovers and moderately sensitive drivers, the E-8s play quite loudly without fear of overload or clipping. At 90 dB SPL above 1 kHz, the THD+N is quite low: below 0.3% over most of the range. Between 50 Hz and 1 kHz, the THD+N is moderate, remaining below 1%.