Recording - February 2011 - 54

B Y M I K E M E T L AY

KRK Systems KNS Series Headphones
A monitor manufacturer’s first headphone designs, put to the test
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/4" TRS adapter, and the other has a twist-lock barrel for a secure connection to the left earcup. Additionally, the KNS-8400 comes with a short-cabled inline volume control with plug and socket to go between the standard cable and the phones. Specs are almost but not quite identical between the two phones. Both offer a 32 ohm impedance, which means they’ll get plenty loud even when connected to the tiniest portable player, to say nothing of pro audio equipment. The KNS-6400 claims 95 dB SPL at 1 mW sensitivity, with 97 dB for the KNS-8400. In simple terms, both phones can get punishingly loud before they distort. Frequency responses are given as 10 Hz–22 kHz for the KNS6400 and 5 Hz–23 kHz for the KNS-8400. As is almost always the case these days (KRK being by no means the only culprit), these numbers are meaningless out of the box because there’s no tolerance in dB listed for them. In other words, saying “10 Hz” is not a useful number by itself; you have to know how many dB down your response is at that frequency, and from what reference point. Oh, well, that’s why we have ears. Listening tests I burned in these headphones with several days’ worth of audio fed through our trusty Aphex 454 HeadPod headphone distribution amp, then set them up with approximately equal SPL and spent several more days listening to a wide variety of music: classical, jazz, electronica/dance music, ambient, New Age, folk, hip hop, and lots and lots of rock and roll of all types. After that, it was off to my studio to track and mix for a couple of days, relying on the KRKs in place of my old-standby AKG K271 Studio and K240M phones. First off, before even turning any music on, I put on both sets of phones and listened for attenuation of outside sounds. The spec sheet claims that the earcups seal out up to 26 dBA of external sound for the KNS-6400 and 30 dBA of external sound for the KNS-8400; in my tests, they didn’t seal out sound as well as my Etymotic Research ER-25 earmolds, rated to 25 dBA reduction, or the very highly isolating Direct Sound EX-29 phones, rated to 29 dBA reduction. Again, it’s hard to make sense of a lone number, since sound attenuation is also frequency-dependent; in my highly subjective tests, while the KNS phones didn’t really qualify as “isolating headphones” (which they are not marketed as, to be fair), there was a very useful reduction in outside sound, making these phones suitable for use in tracking rooms with sensitive mics. I wouldn’t hesitate to send them into an iso booth for a vocalist to use while tracking. Finally it was time to crank up the volume and live with the phones for a few days of constant listening. (You gotta love extended holiday weekends where “Daddy gets some alone time to enjoy his music”, don’t you?) The two phones sounded more alike than different, especially when compared to a couple of other phone designs. They definitely do have a signature “sound” to them, and it’s one that I think a lot of musicians and engineers will come to like. Interestingly enough, I found some parallels between the KNS phones’ sound and the traits that are often associated with KRK’s monitors. With the main difference between the two models being a noticeable extension of the lows and highs in the KNS-8400, the

KRK Systems is a well-established name in the world of studio listening, with passive and active monitors on the market for many years. My first studio project as a producer was recorded with a set of passive KRKs as the main monitors, and I’ve watched the line develop; at the top end we reviewed the exquisite Exposé E8B powered monitors in our February 2008 issue, and in the realm of affordable speakers for entry-level studios and desktop audio applications we reviewed the Rokit and VXT Series in August 2008. Now there are two KNS Series headphones from KRK: the KNS-8400 and KNS-6400. These headphones stand out not only for the familiar yellow triangle logo on the earcups, but also for their very light weight, comfortable fit, and a sound that is promoted as one that KRK speaker lovers will come to rely on. Time to listen for ourselves! The phones Both KNS headphones are closed-back circumaural dynamic designs with swivelling earcups for easy storage. On the outside, there are lightweight polymer casings over spring-steel headbands with easily removable and replaceable earpads and head cushions. Both are made of leatherette-coated foam (it’s memory foam on the KNS-8400) for a high level of comfort—especially on the earcups, which seal nicely against the head. On the inside, both designs have 40 mm neodymium drivers with copper-clad aluminum wire voice coils. Along with the replaceable pads come replaceable cables— both headphones have 2.5m replaceable straight cables, with 1 /8" TRS gold-plated plugs on each end. One end has a screw-on
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RECORDING FEBRUARY 2011

Recording - February 2011

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