Bucking the trend toward powered speakers, KRK has introduced the ST8 and ST6 passive monitors. The company suggests choosing these monitors as replacements for aging passive speakers. However, the freedom they give you to choose your own power amplifier might be reason enough for considering passive monitors, regardless of your current monitoring situation. The ST8 provides a taste of high-end performance at a low-end price: many of the design features of the company's higher priced models have made their way into the ST8.
INSIDE THE BOX
The ST8 features an attractive cabinet, and the beauty is more than just skin deep. The box is constructed entirely from 0.875-inch MDF, a relatively inert material acoustically. The ST8 weighs 26 pounds, which is pretty hefty for a passive speaker with an 8-inch woofer.
Tapping the sides or top of the ST8 yields a well-damped thunk, a sound I identify with much more expensive monitors. The monitors are magnetically shielded, making them safe to use near CRT displays.
The ST8 bears a strong resemblance to other members of the KRK line. Although it's a budget-priced monitor manufactured in China, the overall fit and finish of the ST8 is superb. I have seen other more expensive speakers that were not constructed nearly as well.
The tweeter is a fairly conventional 1-inch-diameter silk-domed unit that is recessed nicely into the speaker's baffle. This mounting arrangement eliminates early reflections that can occur when the tweeter flange rests on top of the baffle.
The woofer is a newly developed unit that features a double-layer anodized aluminum cone. KRK claims that the dual-layer process allows the company to take advantage of the aluminum's stiffness while mitigating the material's tendency to ring. A smoothly sculpted trim ring around the woofer also helps keep the front of the speaker free from sharp corners that can cause sonic problems.
Standard five-way binding posts for speaker-wire connection are featured on the rear panel. Only one pair of posts is included, so biwiring or biamping is not possible.
To audition the ST8s, I placed them on 36-inch-high cement-loaded speaker stands. The monitors were driven by a Yamaha P2201 power amp (a 250W-per-channel bipolar design) that was connected to a Neotek IIIc console. I also used a Bryston 3B-ST power amp during the review process. For listening I played stereo mixes and commercially recorded CDs on a Studer A80RC deck. I also used the ST8s during the recording of pre-production demos by The Originals, a local singer-songwriter duo.
My first impression was that the ST8 has a well-defined and extended bass response compromised by a dark and congested midrange and a rolled-off treble response. I was also surprised by a rather lifeless soundstage. The monitor's sound was almost the opposite of what I expected based on the presence of the aluminum-cone woofer and the sound of other KRK products I have used in the past. In my experience, most speakers with aluminum cone woofers have been bright and strident through the midrange. It was clear that the ST8 was going to challenge some of my assumptions about its lineage and technology.
Manufacturers often put monitors through an extended burn-in period, a quality-control practice that involves pre-stressing the speaker and allowing the suspension structure of the drivers to relax. I felt the ST8 would benefit from a burn-in period, and I decided to take a two-pronged approach to the process.
The first step was to face the speakers front-to-front and wire them out of phase with each other to limit their frequency response. I then ran pink noise through them at a reasonably loud volume for about eight hours. Next, I played several rap CDs at loud volumes. I'm not sure which method helped more, but after the burn-in process was completed, the ST8s sounded much better.
The overall tonality of the speaker hadn't changed — it was still a bit constricted on the top end. (This is reflected in the published frequency response plot.) However, the deficient qualities were reduced from their preburn-in levels.
Even in its improved state, the imaging of the speaker never really opened up for me, and that made it difficult to set levels for reverberant effects and balances between microphones. The speakers also sounded a little bit slow, as though the leading-edge transients were rounded off. I suspect that the rolled-off high-end had something to do with this phenomenon.
The balance of the ST8 is quite good, and the rolled-off high-end may encourage users to add a little bit of top-end sparkle to their mixes. I found that I usually added brightness to compensate for the roll-off, and my ST8 mixes tended to be slightly wetter, because reverb was a bit difficult to get a handle on. Nonetheless, my ST8 mixes held up well when evaluated on other systems.
In a way, the ST8 reminded me of the venerable Yamaha NS10, which had a definite sonic signature but still enabled users to produce good mixes that would accurately translate to other systems. General-use speakers have greatly improved, especially in their low-end response. I think that the ST8 reflects this change. The low-end response of the ST8 exceeds the standard set by the NS10 (and you won't need toilet paper to tame the ST8's tweeters).
Another attribute is that the ST8 can handle loud volumes and keep its composure. I credit this both to its excellent cabinet (which seemed to introduce few resonant artifacts, if any, to the sound) and the stiff aluminum cone of the woofer.
A GOOD CHOICE
The KRK ST8s are a great value. Their cabinets are extremely well constructed and have many of the sonic attributes of the more costly offerings in KRK's product line. While the ST8s are not the last word in transparency and imaging, they are a significant step beyond other monitors in their price range. Once you learn to adjust your mixes to compensate for the speaker's minor anomalies (something that is necessary with all monitors), the KRK ST8s are fully capable of providing a trusted sonic reference.
Richard Alan Salzis a producer and engineer in southern Vermont. His Web site iswww.vtaudio.com.
passive close-field monitor
$499 per pair
AUDIO QUALITY3.5VALUE4.0RATING PRODUCTS FROM 1 TO 5
PROS: Rock-solid cabinets. High-tech woofer. Excellent low-frequency response.
CONS: Shallow soundstage. Rolled-off high-frequency response.
AudioFrequency Response52Hz-20 kHz (±2 dB)Input Impedance8žPower Handling120WTotal Harmonic Distortion<1% at 1WPeak Output90 dB at 1m/1WSpeakersHigh-Frequency Driver1" silk domeLow-Frequency Driver8" double-layer anodized aluminumInput Connectorsstandard binding postsCrossoverCrossover Slope2.25 kHz, second orderEnclosureMaterial0.875" MDFDimensions9.75" (W) × 15.00" (H) × 10.50" (D)Weight26 lb.