Audio/Video, Entertainment, Reviews

Koss SP330 & SP540 Reshapes Music Listening

Two new “stereophone” models are now available from Koss Headphones (KOSS), built from the ground up, for comfortably and portably enjoying music: the over-ear SP540, and the on-ear SP330. First seen at CES 2014, this duo features a smooth blend of comfort, design, and sound quality to enjoy at home or on-the-go.


The most prominent feature of this duo is its ear cup shape, which has roots in Koss’ Pro4AA and Pro4AAA models from the mid-1970’s. When the designers at Koss approached how to improve the music listening experience with the SP series, the “D” shape was a logical choice that was already successful throughout their history. Having a profile that more naturally forms with the human ear lends itself to better isolation, less pressure points, and an enhanced enclosure for delivering audio.


All materials used in the SP series design were chosen for specific functions. A majority of the body is made from a dense plastic blend, providing structure to areas that need to be rigid. The plastic has a soft coating for a smear-free surface and elegant feel. The hinges and internal frame, areas of constant wear and tear, are made of anodized aluminum to provide strength and improve lifespan. The headband and ear cups are lined with soft, breathable memory foam that properly contour a wide range of head shapes.

Somehow, Koss was able to combine all of these elements and still keep things lightweight and portable, even for the longest listening sessions. Let’s take a closer look at both models:

Koss SP540: the not-so-big big brother


At first, the circumaural SP540 seems to be the larger of the two, but both models take up roughly the same footprint. The earcups and headband are just full-size enough to create a proper seal around your ears. Factor in a weight of only 6.6 oz (187 g), and you have a pair that is both snug and comfy for long hours of wear.

kosssp_12Made of premium memory foam and protein leather, the SP540’s cushions are molded to gradually increase in density towards the back and bottom of the cup, evenly distributing pressure around the ear. The headband also has a strip of breathable memory foam inside, relieving further pressure. This result is a sound stage with a pronounced response and isolation.


The SP540 features Koss’ same PLX40 driver elements as their new BT540i Bluetooth model, which debuted earlier this Fall. According to an interview with Koss, the driver type and tuning is identical between the two models. However, the SP540’s improved seal and profile, as well as closer proximity to the ear, accentuates its low and mid-low frequency ranges.

This is especially noticeable for Pop, Hip Hop, and Electronic genres, but may slightly muddy up Rock, Jazz, and Classical tunes. High frequencies are crisp enough without being fatiguing, although vocals could be warmer at times. Overall, the SP540’s sound signature is colored for mainstream music enjoyment.

Koss SP330: soft, snug, and small

For those who prefer on-ear headphones, the SP330 shares the same passion for comfortable listening. Made with the same materials as its big brother, the SP330 also provides a massaged sound that’s great for hours on end. At 3.8 oz (107 g), it’s about half the weight of the SP540, and easy to forget that you’re wearing it at all.


On the end of its lightweight and rigid frame sits two soft ear “pillows”, embedded with the same memory foam and acoustic fabric. The D-profile also improves on-ear listening, forming a similar seal to enhance isolation and reproduction. Because the acoustic grill is situated right over the ear canal, some of our testers have experienced discomfort when accidentally pushing against the ear cup, forcing air into the ear.


Despite its smaller size (and consequently smaller drivers), the SP330 still delivers a rich soundscape similar to its big brother. Because of its isolation, listeners can still get the most out Koss’ PLX30 elements, which provide firm lows and ripe highs. In fact, the SP330 seems to have a better grasp on lower frequencies than the SP540, allowing just enough without dulling the mid range.


Both the SP330 and SP540 include a detachable 4-foot, 3.5 mm TRS cable that plugs into a recessed port on the left ear cup. All of this folds flat into a soft clamshell case, ready to go for its next session.

Continuing the legacy

“We take a lot of pride in meeting people who’ve used the Pro4AA that they’ve had for many decades,” recalls Michael Koss Jr, Marketing Director of Koss Corporation, “One of the things we thought of when designing [the SP series] was trying to ensure the same type of legacy with them, so that thirty years from now, folks could come up to us and say the same exact thing.”

“I think that’s what sets us apart as a brand. If you think about it, especially in consumer electronics, there’s not many products out there from 30 years ago that are still functional and operate well. So I’m very proud that we come out with products that can stand the test of time.”


While it may be early to tell if the SP series can withstand such a lifespan, Koss is confident that their new headphones are built to last, backing them up with a lifetime warranty. Reading reviews on Amazon and other retailer sites, the initial feedback of the SP series has been very approving, all pointing towards a true bang-for-your-buck experience.

At $129 and $149 USD respectively, the SP330 and SP540 delivers premium listening and comfort at surprising value.