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KRK Systems KNS-6400 and KNS-8400 Series Studio Headphones

KNS Series headphones provide pleasing performance, adequate isolation and excellent comfort thanks to lightweight, ergonomic design.

The recent surge in higher quality headphone models hitting the market should come as no surprise; every new DAW needs at least one pair of cans to go with it. Thus, KRK has just introduced two headphone models of its own, the first from the company’s new KNS Series. More similar than different, the KNS-6400 and KNS-8400 models are unlike many competing models and are priced to be serious contenders in the burgeoning headphone market.


Both the KNS-6400 and the KNS-8400 are closed-back, circumaural (surrounding the ear) dynamic headphones with 40mm neodymium drivers, featuring 2.5-meterlong, straight cables with oxygen-free wire that terminate in an 1/8-inch miniplug with a screw-on 1/4-inch adapter. The cables, ear and head cushions are all userreplaceable.

What’s the difference between the KNS- 6400 and KNS-8400? Well, it’s primarily a difference in foam: the KNS-8400’s ear cushions are made of “acoustic memory foam,” as described by KRK, and covered in a supple “premium leatherette,” reportedly securing up to 30 dBA in ambient noise isolation. The KNS-6400’s ear cushions are “acoustic cellular foam” and standard leatherette with 26 dBA noise reduction. Also, per KRK’s specs, the KNS-8400 provide slightly deeper bass response, slightly higher treble response and 2 dB greater efficiency at 97 dB SPL @1 mW (at 36 ohms impedance).

In Use

Compared to my varied stable of six different headphone models, both KRK models kept up with the pack, excelling in areas of high-end clarity, lack of distortion and accurate transient reproduction. As of late — and following our Session Trial on Premium Headphones — I divide headphone evaluation into four application categories: tracking, overdubbing, mixing and casual listening.

Here’s what I discovered for those applications, per KRK model:

I found the KNS-8400 to be good for tracking, offering minimal fatigue on the top end, slightly scooped out low mids (around 200 to 400 Hz) and just enough bottom. In particular, the lack of high-end hype is appreciated for long or loud tracking sessions, and the bottom end is slightly plump without being too “poofy” or having “one note bass” syndrome. In direct comparison, I still think that the Audio- Technica ATH-M50 provides the deepest bass response for the insatiable needs of drummers and bassists, but both the KNS-8400 and KNS-6400 are lighter in weight and a bit more comfortable. The KNS-6400 doesn’t provide quite the same low-end bump, nor the high-end extension as the KNS-8400 and conversely had a low-mid emphasis (similar to my Fostex models), but still had the same clarity and openness as its pricier KRK counterpart.

For precisely those characteristics, the KNS-6400 would be preferred for instrument and vocal overdubbing applications. Their increased midrange focus and lack of distracting bottomend thump helps singers and instrumentalists focus on pitch and melody. I found that performers liked both KRK models for overdubs (split 50/50 between KNS-6400 and KNS-8400), and those same performers often preferred the leanness and mid-definition of the Sony MDR-7509 (except without their pronounced high-end bump).

I’ve said it before: I’m not too keen on mixing with headphones. Even if you get the bottom end right (like the A-T ATH-M50 may allow you to do) and the high end clear and reasonably flat (like the AKG K240 may allow you to do), the mids will be the challenge. On headphones, I’ve found it’s generally a big guessing game for these most critical of frequencies. That said, these KNS Series headphones get pretty close to “mix-worthy.” If only I could combine the KNS-8400’s deeper bottom and sweeter top with the un-scooped mids of the KNS- 6400 … well, actually those mids are a little forward. Split the difference between the KNS-6400 and KNS-8400 and I’d have something I could really trust.

For casual listening, I can highly recommend both models. Their clarity, isolation, low weight, fold-ability and comfortable ear pads make an ideal headphone experience. The only question is which model? I’m thinking most folks would prefer the additional bass response and scooped low-mids of the KNS-8400, but those really into vocal music or detailed instrumental music (think classical or bluegrass) might just approve of the flatter mids on the KNS-6400.


I think that both models in the KNS Series provide adequate isolation as well as excellent comfort — even when wearing eyeglasses — aided by their lightweight and ergonomic design. Compared to my own headphone stable, other models have deeper bass, more bass definition, more openness, a clearer top or a plusher fit. But the KNS models were a runnerup in most categories, making them very utilitarian and versatile. I must admit how much I like the removable (and replaceable) cables, and that the KNS-8400’s optional inline volume control is useful and sturdy to “pro-grade” standards.

For studios that need to track, overdub and possibly mix in the same cans, I would highly recommend the KNS-8400, especially considering its apparent reparability. Because both the KNS-8400 and KNS-6400 are available at affordable prices ($149.99 and $99.99 street, respectively), it might be wise to have both at hand to suit the varied needs of performers.

Prices: $199.99 and $129.99 list (KNS-8400 and KNS-6400, respectively)
Contact: KRK Systems | 954-949-9600 |

Rob Tavaglione owns and operates Catalyst Recording in Charlotte NC.