A Sonic Stunner: The Koss SP330 On-Ear Headphone

Some introductory thoughts on Koss.
I have to admit significant mixed feelings about Koss. On the one hand, they've produced some truly excellent headphones in terms of value/dollar. The Porta-Pro (reviewed here), KSC-75 (and earlier variants), and ESP 950 headphones have had a strong following and fan base in the headphone hobby since day one. There's even a meme of sorts among enthusiasts giving advice to novices entering the fray, "Buy a set of Porta-Pros, then, if you can find something better, get it." Many experienced headphone enthusiasts still have one in the stable...I do.

On the other hand, Koss has many headphones that are pretty poor. My first headphone ever was a Koss Pro4AA back in the mid-70s. Unfortunately the current model is a mear shadow of it's former self, and the sound quality is atrocious in my opinion. I think they should cull the herd a bit.

Koss_SP330_Photo_StockPerformanceKoss as a brand also suffers from a remarkably old school vibe. Say the word Koss, and the first thing that comes to my mind is Radio Shack. Many of the headphones they carried were re-branded Koss models. These days, both companies suffer from tired brands.

A tired brand alone is enough to kill a company, but Koss has seen even worse troubles in the last five years. In 2010 Koss had to fire their VP Finance, Sue Sachdeva, who embezzled some $34 million from the company over the course of ten years. With only $40 million/year in gross sales Sachdeva's criminal behavior surely must have wasted the lion's share of profits.

Koss has also spent some $4.5 million on developing a wireless headphone system that appears to have had significant trouble, and are currently in court with the design firm that worked with Koss on the project.

For a very nice overview of Koss' current situation see this article.

All told, it seems to me Koss has had a very rough ride. Something has to go really right, really soon, or they may go the way of Blockbuster, Kodak, or Sears. Change, get relevant, or die. At this point I think Koss really needs to focus on what they have always done well: Make good performing, low-cost headphones.

The good news is that with the new SP330, they've done just that. I'll add that their new SP540 and Pro4A are decent performers as well, I'd say above average in their categories, but for me, the SP330 is outstanding.

Koss SP330 ($129)
The SP330 is a compact, sealed, on-ear headphone. The styling of the SP330 is simple and understated. Major parts are a soft-to-the-touch matte black plastic with chrome and brushed aluminum accents on the headband and earpieces. Earpads are protein leather over memory foam; the headband pad is black mesh fabric over memory foam.

Due to its very light weight, the SP330 is a very comfortable headphone, but I found because of its very compact size it does take a bit of fidgeting to get it properly adjusted to fit on my head. Caliper pressure may also need to be adjusted for best bass response. I found the headband extension arms can be gently bent to provide just the right amount.

Earpads rotate flat for storage and transport, but lack any folding mechanism to significantly reduce size. I've got mixed feelings about this: These are very compact headphones and could be made more so with a folding mechanism, but those mechanisms are also prone to failure.


Accessorization is a bit thin. The cable, at 54", is just about right for portable applications, but lacks a remote/mic for phone use. The carry case is a rectangular hard-side case, which is good, but Koss seems to be saving money by using the same case on many of their current models and just changing the internal molded insert for the various cans. This, unfortunately, means that the carry case is significantly larger than need be for these compact headphones.

In sum, I think the physical build of these cans is a mixed bag. I'd like to see them at $99, which might eventually happen, but at $129 they seem just a bit overpriced. Until you start listening...

Sound Quality
Stunning really, completely unexpected. This is really a terrific sounding headphone at the $129 price.

Overall, I'd characterize the SP330 as a neutral sounding headphone. Bass quality, punch, and extension is very good, but quite reliant on getting a good seal and proper position on the ears. Increasing caliper pressure by bending in the headband extensions goes a long way to achieving good bass response, as does just letting them warm up and settle into your ear shape. Bass to mid-range transition is excellent—no thickness or bloat in the low-mids at all.

The mid-range is wonderfully clear and even. Listening to mid-range elements at loud levels can often lead to a hard and shouty character, the SP330 seems to take it all in stride without breaking a sweat. Mid-range to treble transition is also excellent. Many headphones tend to fall off excessively above 1-2kHz, the SP330 remains very flat up to the mid-treble and as a result have a very present and close-up character. I very much get the feeling of row one seating with these cans. Want to hear the saliva on the sax reed? The Koss SP330 will do the trick.

The only area I have issue with is somewhere in the upper half of the treble. Sometimes very fast transients will take on a slight metallic "ting" sound, or overly pronounce cymbals. The resolution and transient response otherwise is wonderfully articulate and natural. For all of you who know my tastes, the SP330 is just a tad bright for me, but I think most would call it right down the middle with an excellent over-all balance.

I did spend a bit of time comparing the SP330 to comparably priced headphones. In comparison, the Onkyo ES-FC300 was a bit bass excessive and loose; the Philips Citiscape Downtown lacked the resolving power; and the Noontec Zoro HD sounded somewhat rolled-off. The SP330 has great sound quality relative to other ~$100, ear-pad, sealed headphones.

As an audiophile, I get pretty disappointed when a headphone nails styling and comfort, but falls flat with sound quality. The Koss SP330 is somewhat the reverse: The build falls a little short, but the sound quality is way better than the price would suggest. Seems to me, if you are going to fall short (and they all do one way or another), this is the way to do it. You give me great sound, and I'll forgive a few warts.

Yup, the SP330 is going up on the "Wall of Fame" based largely on its on its outstanding sonic performance. It does fall a little short on some peripheral issues (doesn't fold, no mic/remote, case is large, a bit underwhelming in design at the price), but to my ears, and to those who care about sound quality, this headphone is a big win for Koss. Whether it's a big enough win to give the company a much needed boost, I don't know...but it's a great start.


Koss home page and SP330 Product page.

Koss Corporation
4129 N. Port Washington Avenue
Milwaukee, WI 53212

Seth195208's picture

..this doesn't get "you know who" started again. Wow! Outstanding measurements!

Argyris's picture

I've been waiting for this review for quite a while, ever since I saw these mentioned in the gift guide. Thanks for taking the time to write this up, Tyll.

Wow. I figured these would be pretty good when I saw the measurements, but of course there's no substitute for actual listening. Based on your impressions, these sound right up my street. Koss might well be getting some of my banked up Amazon gift card credit in the near future...

...except that the SP330 has been out of stock on Amazon for weeks now. Looking at the review section on the SP330's Amazon page, I can surmise that Koss made sure a lot of people got free samples to review (ideally favorably), and that's where most of Amazon's initial stock went.

Personally I don't have a problem with consumer review programs (as long as there's proper disclosure, and in this case there is), but I do think that Koss might have inadvertently shot themselves in the foot here by not having the SP330 in stock on one of the largest retail sites in the world during holiday season. Dozens of positive reviews of an unavailable product might just infuriate prospective buyers and drive them elsewhere, since the "deadline" (Christmas) is less than a week away now. I really hope this doesn't happen.

Incidentally, I'm still trying to decide whether to wait for the SP330 or shoot a bit higher up the price chain for the V-MODA XS. If you don't mind me asking, Tyll, how would you say they compare SQ-wise, and which do you overall prefer and why?

Thanks for taking the time to read this.

zobel's picture

They list 5 pairs currently available tonight (Dec. 20th).

Argyris's picture

A belated thanks for the heads up on that. By the time I got around to checking, they were gone. However, by quite a stroke of luck, about half an hour ago at time of posting this they had one...ONE...in stock, which I promptly snapped up. It arrives Dec. 30th, alongside an NAD HP50. Pretty stiff competition, if what I've read on IF and elsewhere holds up.

fzfan's picture

I am a long time follower and first time poster.
I have a pair of 1970s vintage Koss Pro 4AAs I have owned and used since acquiring them new "back in the day". I have never seen a review of vintage headphones that could compare them with todays models. I find the Pro 4AAs somwhat dark (pronounced bass with recessed upper mid/treble).
I'm curious if IF has done vintage can reviews, specifically, the Pro 4AAs. I would be interested to know how these measure, etc. as well as another's objective/subjective opinion.

Sweden's picture

This FR reminded me a bit of the Fostex TH-900.
Yeah I agree that Koss best bet is in the budget segment.
But why make the design so boorishly unsexy? This won't fly with kids dammit.
I think that what we are seeing is headphone evolution at work. The companies who can't produce nice looking portable headphones will go extinct. It doesn't matter how good the sound is, if they look clownish or to bland on your head people between 13 and 40 won't buy them.
I'm my country has the fabulous sounding Visio HP50 sold very poorly. They look a bit weird when worn unfortunately which is my best bet for their lack of success.

Personally I'm hoping for an updated electrostatic headphone. Something with the sound more in line with the Stax SR-507, but with much better comfort and a price tag around 500.
Skip the amp this time Koss unless you can hire a guy like Birgir as a designer.

forkboy1965's picture

Thanks for including the link to the article. Nearing 50 rapidly my experience with Koss is just as you describe... a stroll down Radio Shack memory lane.

What I found slightly disturbing from the article was how dismissive Koss seems to be of design flair. Personally, I find Beats and their like unattractive... more like kids toys than audio equipment. But that doesn't mean it hasn't worked for them and others.

To ignore that fashion has a decided influence on headphone design seems to be sealing your fate for failure. They don't have to be flashy, neon, plastic-shiny colors, but some sense of modernity and design couldn't hurt.

After all, quality sound and an attractive housing aren't mutually exclusive. Maybe it is time to trade-in that bow tie for something different?

Argyris's picture

I agree completely. I think something Koss hasn't considered is that Beats et al. became so successful so quickly because they offered (at least in appearance) something different from the bargain bin, blister pack, fashion-last products that, quite frankly, the likes of Koss and the big box brands had been offering consumers as the only choice for over a decade. Making the same kind of stuff consumers feel they've finally escaped from, even if the guts sound better now, isn't likely to be a winning strategy in the long run, IMO.

I agree with Koss that chasing pure fashion is probably a fruitless endeavor, and celebrity endorsements are not only expensive but are likely to be seen as "me too" efforts to compete with Beats. (One wonders how many rebadged PRODJ100s Tony Bennett's endorsement moved...)

However, there's a big difference between making an all-fashion, no substance product, and making something that has at least some modicum of style and is durable, has good ergonomics, and performs well. Protip: When in doubt, make it metal. Also, a quirky advertising campaign might not hurt.

I think Koss is absolutely capable of pulling off something like this, but the company would need to be willing to shift focus away from just raw performance and value. They should look at products like the HD25, the DT1350, or pretty much anything from V-MODA for inspiration--all represent good (though different) balances of style, build, ergonomics, and performance--then make something similar that targets a lower price range. If they made it perform as well as the SP330 is reputed to, and offered it for around $100 USD (maybe a bit higher, especially if there's a lot of metal in the construction), I think they'd have a bona fide hit on their hands.

tony's picture

Koss needs a bit of help, thanks. I'm from Wisconsin so what you do for these souls you do for me, in a kind of way.
I'll buy a pair to gift, I'll buy a matching JDS from St.Louis too, a nice little "Fly-over Country" music system.

Tony in Michigan

ps. if it ends-up being as good as you suggest, I'll get one of these little systems for myself - to show-off: "see, we make stuff like this in the Midwest"

Thanks for the nudge

Long time listener's picture

Tyll, you mention that cymbals were overly accentuated, and attribute that to the region at 10Khz and above. But it seems that in your other comments, you've already identified the problem: "the SP330 is essentially flat to 4.5kHz. In listening, this made them sound very present, first row seating. Normally I'd be wary of that as things might get strident..." I think you're right. I bit more of a dip around 4.5 Khz would be appropriate. Cymbals do have sonic content at that frequency that will be heard. It seems to me that the response at and above 10Khz is about the same as we've seen in millions of other headphones. Even though there's a small peak at 10Khz, it's still lower than the midrange, and the response drops off sharply above that. My opinion is that there isn't likely to be a problem there.

Jim Tavegia's picture

With the "25gift" promo code an even better buy.

Stillhart's picture

How would you say they compare to the M80, Momentum On-ear and the venerable Creative Aurvana Live? I consider all these to be in the same price point and in direct competition.

I've owned the MOE and CAL and I prefer the sound of the CAL by a lot. The build quality leaves a lot to be desired, however.

JRAudio's picture

I friend of mine and I just bought this headphones (one for each) and must say, yes for the price, it is a good sounding over the ear closed headphone (if you attached it correctly to the ears) but,

even without a real use, both headphones have mechanical problems on the rotating mechanism of the left channel (where the cable is connected to).

The rotating mechanism on the right channels is working fine, so it has concrete end points for and does not get loose,

but that of the left channels, you can rotate “endless” and it gets loose and fall off just after 3 to 4 slowly + / - 45 degree rotations.

Can someone, who also owns this headphones, can comment, if this is also the case?

We will send both back and hope for betters ones next.

Best Regards

Guitarist9273's picture

compare to the best on-ear headphones? Regardless of price. Like the v-moda XS, the Beats Solo 2, etc.

iraweiss's picture

I have had a pair of Pro 4AAA Stereophones since the 1970's. About a year and a half ago I called them as the ear cushions had died. Low and behold I was able to purchase a new pair of cushions for $5. This kind of support (with the rare exception of a few companies like Definitive Technology or oppo) is unheard of these days.

They were easy to replace and the phones still sound great. Their isolation is perfect for watching TV or a movie or listening to music while on the treadmill.

I too would love to know how these vintage headphones compare to contemporary models.