Koss PortaPro - Headphones ( semi-open )

General Information

This high quality portable stereophone set performance and comfort standards for personal listening worldwide. Over the years, much to the delight of devout PortaPro enthusiasts, Koss has preserved the original design and performance that made the PortaPro a portable music icon. Today the PortaPro remains the headphone of choice for the discriminating listener.The PortaPro features dynamic elements that deliver exceptionally rich, deep bass and a remarkably wide frequency response from 15 - 25,000 Hz to capture every nuance in your favorite movie or musical performance. Constructed from mylar, the elements are extremely rigid, minimizing mechanical distortion and ensuring exceedingly accurate sound reproduction. Neodymium iron boron rare earth magnet structures enable the PortaPro to deliver greater volume so you can hear every note, even when competing against the sounds of a commuter train with a low-voltage MP3 or disc player. Oxygen free copper voice coils improve signal transmission and conduction for cleaner, clearer sound. Foam earcushions provide an open, hear-through sound that lets you keep in touch with your surroundings perfect to wear while running, at work, or while traveling. Whether you're listening at home or on the go, the PortaPro will bring the excitement of a live performance to any recording.

Latest reviews


New Head-Fier
An easy recommendation
Pros: Macrodynamics
Cons: Flimsy build
Recessed treble
Full review: https://jamesfiorucci.wordpress.com/2023/01/16/simple-audio-review-koss-porta-pro/

Recently, my dad had been complaining about his ear buds not fitting him correctly and constantly falling out. This had curtailed his music listening enjoyment, so in an effort to help him appreciate good music again I bought him a pair of Koss Porta Pros.

These are on-ear headphones, and thus aren’t going to fall off nearly as easily as a pair of IEMs. Furthermore, I had heard great things about the Porta Pros, lauded as one of the best sub-£50 headphones that you can find on the market today. I was sure he was going to notice the increase in sound quality (and comfort), but a couple hours later he handed them back to me with a disappointed look and said he didn’t like them.

I have my theories for that, which I’ll touch on in this review, but I decided to just keep the Porta Pros for myself and see (or listen) to what all the fuss was about. And lo and behold, I was immediately taken aback by the sheer value that these on-ear headphones present to the industry. Let’s dig deeper!

Comfort and Build

The Koss Porta Pro was designed in the 80s, and you can see that in its retro look. It’s crazy to know that Koss are churning these out new even to this day. Unfortunately, the retro influence stretches to its build too, with an almost all-plastic housing and thin metal headband. You can’t afford to be too rough with these cans.

Nevertheless, I found comfort surprisingly good with the Porta Pros. Weighing a mere 60 grams including the non-detachable cable, I find that they simply disappear on your head. Since the clamp isn’t too loose or too tight, the lack of padding on both the ears and headband don’t cause any comfort issues. I didn’t find myself ever using the “ComfortZone” toggle on the sides, but I guess that’s an added benefit to have.

The mechanism for adjusting the size of the headband is a weird one; let me explain how I found was the best way to fit the Porta Pros correctly on your head. First of all, adjust the black sliders on the headband to maximum size and put the headphones on your head. Then simply slide them in the opposite direction to reduce the size until it is secure. Just try not to get any hairs stuck in the gap between the metal sheets of the headband; trust me it hurts!


Expectations were low for such a cheap pair of headphones which look like they could come out of a McDonald’s Happy Meal, but these blow all assumptions out of the water as soon as you hit play on your favourite tunes. Of course, there are a few shortcomings, but they’re really only noticeable if you go searching for these faults.

The drivers found on the Koss Porta Pro were designed and first manufactured in 1984, so it is of no surprise that they don’t quite extend down to the lowest frequencies. This will lead to some genres, such as grime and EDM, to sound somewhat lacking.

Strangely enough however, bass is one of the redeeming aspects of the Porta Pro. There is a significant mid-bass bump which gives a satisfying level of kick and thump to instruments that demand it, such as drums and bass guitar. It also contributes to an overall warm tonality, which results in a thick and full-bodied weight to the music. I tend to prefer a warmer sound signature so I like this characteristic of the Porta Pro, but I understand it is not for everyone.

Honestly I don’t have a whole lot to say about the midrange. Despite the mid-bass emphasis, the mids don’t feel recessed whatsoever and have a naturalistic timbre that bodes well for the vast majority of instruments.

The upper midrange does come across as “shouty” on some tracks, but that has more to do with the recessed treble region that I will get onto in a little bit. For this reason, female vocals can seem to overpower the rest of the mix. This, along with the proximity of the drivers to the ear canal results in listening fatigue for me personally, but it does take a few hours to kick in.

The recessed treble is probably the reason why my father disliked the Porta Pro’s sound, which is understandable. What I would describe as “warm and relaxed”, he would call “muddy” and lacking in absolute detail.

It’s crazy how some songs sound completely different with the Porta Pros. Those sparkly notes, cymbals and such are so incredibly blunted as to make you do a double take in certain passages of music. But for the £35 I spent on them, I can look past this flaw.

Soundstage and Imaging
This ain’t no three-blob affair. Imaging is actually decent on the Koss Porta Pro. Every note and instrument feels as though it has it’s own defined space in the room, but said room does feel kind of small. I’m talking about the soundstage of course; it’s relatively narrow. But the focussed imaging is one of the first merits I noticed about the Porta Pro, as its leaps and bounds ahead of any other headphone I’ve heard at this price point outside of the Koss ecosystem.

Due to how close your eardrum is to the drivers, you get an impressive level of attack and decay on the edges of notes, which is perceivable as detail. Music sounds sharp and each note well defined, except maybe in the treble region which as mentioned before, is quite recessed and therefore muffled.

On very busy sections of certain tracks however, the driver seemingly has too much to do and gets a little lost, losing out a bit on resolution. Totally excusable at sub-£50, however.

Overall Verdict
The Koss Porta Pro deserves to be merited on its sound quality alone, not just on its absurdly low price tag. But at such an affordable cost this is an easy recommendation for any audiophile, from the beginner to the serious collector. Prepare to be surprised, in a good way.

Rating: 7/10


100+ Head-Fier
Missing the Era of Walkmans?
Pros: Affordable
Light and Portable
Good Timbre
Warm Tonality
Fun Sound
Safe Tuning
Intimate Vocals
Cons: Unusual Headband
Somewhat Muddy
Not very technically capable
This full review is also posted at mobileaudiophile.com

Koss Porta Pro

Koss brand is kind of a legend among audiophiles. They were very popular during the golden age of Walkmans. Although much has changed in the music listening habits of people, Koss Headphones stayed on the scene due to their good sound and affordable prices. Porta Pro is the most famous and one of the oldest entries in their product line; a legend among the legends.

Koss Porta Pro


Without boring you too much, I don’t necessarily have a sound preference. I tend to enjoy different sound profiles as long as they do well what they intend to do. I’m not very sensitive to treble so I can enjoy the most notoriously bright headphones, however I’m somewhat sensitive to upper mids area. Please keep these in mind.

Built, Comfort, Trivia

Porta Pro, like the name implies, very light and portable, comes with a pouch and has a pretty complex headband for a portable on ear headphone. Headband has a comfort setting which changes clamp force and possibly sound a little. Also it has no memory of your choice of length or comfort setting. The headband may pull your hair when you try to adjust the headband length, but that’s not a big problem for me as I hear for the others. They don’t seal and isolate well. You can even call them open back or semi-open back headphones in this sense. Sound profile also confirms this claim.

Koss Porta Pro


These have a significant sub-bass roll off like most open back dynamic headphones. But the presence of the mid-bass hump makes you forget this absence, unless you are a “wub wub” addict. I am not. They are very dynamic in this sense and can punch pretty hard. Not very fast, but I never felt ends of tones lingered more than they need to.

Mids are warm, lush, somewhat muddy, if you compare to more neutral or technically correct headphones. Frequency Response Graph may suggest otherwise, but vocals are really a strong point of Porta Pros. Somehow they come as intimate and very appealing, at least in lower frequencies, until 2k hz or so.

Koss Porta Pro

As you go higher frequencies, Porta Pro insists on staying warm and maybe dark, of course again if you compare it to more neutral headphones. They are relaxed, smooth and easy to listen to. Treble does not extends too high, which is again contributes to the relaxed tone.

About the timbre, this is I think where the Koss headphones shine. Porta Pro has a warm tonality but nothing sounds weird or off. Every voice come as natural. They have a very fun sound which is not fatiguing in any way. They don’t extend too well in the highs. Soundstage and imaging are average. These are not very technical headphones per se. But tonally very well balanced which is not expected in this price range.

Koss Porta Pro


I like Koss Porta Pro headphones a lot. If I don’t like something, I immediately sell them but these are mine and here to stay. Maybe I don’t give them much time. After all, I have lots of headphones and IEMs, most of them are more expensive and capable than these. But I still sometimes take them with me when I go out to grab some groceries. They are very comfortable and portable. And their presentation is like a window to the vast audiophile world. Intimate vocals and impactful bass is a delight. If you need an affordable and decent pair of headphones or don’t want to take your expensive pairs out, give Koss Porta Pro a listen.


500+ Head-Fier
Pros: Very punchy and fun; non-aggressive
Cons: none at this price point.
Over the years I've acquired more than a few keyboards, CM, ducky, DAS, you name it. Guess which one's my daily driver? IBM Model M. It's turning 31 this year, but its every bit as good as its modern siblings. In my headphone collection I have HE6, LCD2 Rev.1, HD600 and Porta Pros. Guess which gets the most head time? Porta Pros.

Switching back to porta pros from any other headphones feels like going home. It's a sound signature I'm familiar with, and I can very comfortably sit down for hours with these on my head. Okay u say, where's the subbass? Missing. Where's the treble? Muffled, completely cut off above 10K. None of other headphones in my collection exhibit these problems, but none of them gets this much love.

There is a reason why portapro remains popular after 3 decades. It's non-offensive nature, its powerful mid-bass, its mids. There are a list of things I can say about PortaPros but let's not forget its a headphone engineered 3 decades ago, and it unmistakably exhibits that kind of sound you'd expect from the 90s.

None offensive in nature, yet highly dynamic and engaging. Porta Pro has that sort of power that sucks you into music without thinking about gears or anything audio related. I can definitely notice the missing subbass switching back and forth between these and LCD2s, the endless treble extension of HE6 also put these to shame. But the mid is among the most life-like I've ever heard. It's very muffled yet highly realistic. It conveys the emotion even Utopia fails to bring out, and romanticize it 1000 times more. There you go. A sound addictive like no other. Adding sub-bass or treble extension would kill portapros, cuz that's what makes them unique. I use them every day for more than 8 hours since I first bought em in 2002, and if u ask me to keep only one headphone, this is the one. It happens to be the cheapest one, but over the years it has proven itself to be the most loyal companion. My one and only safe house. To anyone out there who wants to buy one, don't be fooled by its price tag. There're only two headphones that'll drive you to tears: Orpheus and PortaPro.


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