Koss PortaPro - Headphones ( semi-open )


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.


100+ 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.


100+ Head-Fier
Pros: Great sound clarity and details, lightweight, comfortable, punchy bass, lifetime warranty
Cons: Old looking design, headband that will rip off your hair, leak sound in and out, not quality cable
These headphones are well known for its low price and quality. I think they should be called shockers because when you look at them its one thing but when you listen to them suddenly they change to the most expansive cans you can get :)  Sounds is really impressive, something you must try. 
Overall great headphones. I actually prefer the design of Sporta Pro not Porta Pro... I had both so I took speakers from Porta Pro which are better and got them into the Sporta Pro headband which looks cooler. I also put double pads on both sides so they are a lot more comfortable. These are great for travelling where you dont have much space to take them with as they fold into pretty small compact size.
Koss should really reconsider to change the design of these as the headband could be done better way, they could try to make a closed version of these, replaceable cable and maybe rotating cups then they could seriously compete with HD25 from Sennheiser. The fact they do leak sound in and out makes them difficult to use outside which I find the biggest issue with these. Forgot to mention the cable quality should be improved too as it intend to break when you wearing them outside due to the hot / cold weather. This happens to all of them and I have 3 pairs.
I always wanted to try some other models from Koss but haven't had the chance.
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100+ Head-Fier
Pros: Price, comfort, mids, upper bass
Cons: Poor sub-bass, fluffy treble, build quality
From 100 Hz to 3000 Hz, they trade blows with much more expensive headphones, and that is not hyperbole. That is why so many people love them.
Above and below those cutoffs... no of course not.
But still, the mids are crunchy and savory. The highs are smooth yet detailed enough to be enjoyable. The bass is warm but reasonably tight, and certainly not bloated. The sub bass is nonexistant, the upper treble is lo-fi. But these little bastards cleverly stylize their deficits to mask their impact on the sound. It's an enjoyable filter that you can view your music through, that isn't the highest in fidelity, but it's faithful and playful enough to be enjoyable for what it is. Don't EQ these (it'll just reveal how flawed the upper treble really is in painful detail). Just listen to them as-is, think of it as a flavoring for your music.
Another thing is that just about any crappy hardware can power them. And they will take the worst onboard DACs and the most cringeworthy recording qualities and even the oldest and most unlistenable 128 kbps mp3s and they will make something tolerable out of those. They are the ideal consumer-grade headphone, basically.
Comfort... is a mixed bag. The headband will make you bald if you're not careful. The hook will dig into your right ear if they're sitting wrong.
Build... they're $30. What do you think?
In summary... These are great starter headphones. I would strongly recommend them for students on a budget, as I was a decade ago when I first bought these. Going further with your sound requires significantly more research, time, and money. If you don't want to fall into that hole, this is a good stopping point right here. I still enjoy these guys. I've had them for 11 years. I've bought 4 during that time. Two got stolen, one broke (now I keep two at all times so I have one spare in case the other breaks). One other interesting thing is that they're easy to open up and repair. I've soldered the wires back on multiple times after snapping them with a doorknob, and they still work great. Even if you've been exposed to higher def headphones, if you listen to these for a while, their easy-going nature and crunchy, savory mids, will win your heart once again.
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The Koss Portapro was a decent buy when it first came out over 20 years ago. Imo the JVC HAS160 for around $10 sounds better than the Portapro. I bought the Portapro in the 1990s and am very familiar with its lack of treble and murky bass. The JVC HAS160 is closed but doesn't isolate so well, so it is a bit different than the Portapro. Imo the $15 Koss KSC75 headphone with ear hooks sounds much better than the Portapro in terms of both midrange detail and treble. If someone likes the form factor of the Portapro and is willing to pay more, the Sennheiser PX100ii at around $47 has so much more detail than the KSC75(and of course much more than the Portapro). I have the original PX100 and like it very much. The PX100ii adds a bit more bass, and has the cord on just one side. Both fold to a very small size.
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I never detected much of a difference in quality in the KSC75, and preferred the warmer tuning of the PortaPro, but I'd agree cost/quality the smaller brother is a better deal. I wouldn't be surprised if there are much better things in the price range these days, particularly with IEMs, which seem to be moving quickly. The Philips SHP9500 is just a hair more expensive at $57 and definitely beats the Porta Pros by a good distance, and you get quite a lot more hardware for the money as well. Probably gonna bump my review down a bit.
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New Head-Fier
Pros: They nailed it; pure enjoyment of music in a comfortable, fun-looking headphone with a killer guarantee.
Cons: You might get mistaken as a hipster. They're not a replacement for studio monitor phones. The ear-cup foam will degrade over time.
Market niche: To provide a high level of musical enjoyment at an affordable price.
Obstacles: People associate cost with quality. Fashionable name brands, aesthetics, compactness, and gimmicks (noise cancellation) command a higher priority in today's market.
I'm one of THOSE. You know...vinyl is superior to digital. Tube amplifiers beat solid-state. FLAC files only. Definition, soundstage, separation, muddy/boomy/punchy. No replacement for displacement...drivers, magnets, cone construction. Yup. Guilty. 
But I'm going to say it; for pure portable musical enjoyment, I reach for these every time. They aren't "accurate" headphones. They look dorky. They leak sound. The foam muffles some of the frequencies.  But at the end of the day, we listen to music to FEEL something. Nostalgia. Sadness. Jubilation. Air guitar. Steering wheel drums. Head bobbing. A heart that skips a beat. Gall-darn it...the Koss Porta Pro makes you want to pull a Risky Business and run around the house in your underwear. Or cry while you wash dishes. Or daydream while you go about your daily business. Or sing along and actually hear yourself (sorry, closed-ear phones). 
The Koss Porta Pro is the guilty pleasure hamburger of headphones. If I want a 5 course meal with foie gras, Filet Mignon and Lobster tails, I'll cocoon into my Audio Technica MTX-50's. If I want a spicy thai stir fry or tasty sushi, I'll borrow my daughter's Audio-Technica MTX-30's. Nevermind the Dr. Dre Beats Solo and Bose Soundtrue II and heap of Apple earbuds stashed in a drawer somewhere around here. For pure comfort food, there is only one choice: Koss Porta Pro. 
Just buy them. And shave your face, unless you like being identified as a Hipster. 


Headphoneus Supremus
Pros: "Listenability", Warmth, Soundstage, Lack of Irritants
Cons: Treble Roll Off, "Fold" into a round rather than flat shape
So, 35.00, 40.00?
What do you get?
Very good sound, outstanding comfort,
a lifetime warranty.
It's a warm sound.  Plenty of bass, not too much IMO,
significantly rolled off treble.  Smooth midrange, not
overly present or recessed.
So light that they apply just a touch of pressure to
the top of your head and your ears.  Mostly your ears,
and its softened nicely by the ear cushions.  Very
comfortable, so that they can be worn for hours.
Clearer and more sonorous than the somewhat
competitive Sennheiser 100 II.  Better bass and
generally similar build quality. More comfortable
as well.  To my knowledge, there is no other
competition in this category.
The PortaPro > very, very comfortable, light in weight, inexpensive,
suited to a wide variety of music, sound far better than their price could ever indicate.
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New Head-Fier
Pros: really impresive sound quality and good soundstage, value master due to koss lifetime warranty, no need to amp them, really portable
Cons: hair ripping, can't be worn around neck, not the most comfortable to wear, cable tends to break, hair gets under the membrane, leaks music
Porta Pros simply made the biggest difference for me when listening to music as I have switched from some low-end sony in-ear to them and suddenly when playing the same song music became more rich and colourful and instruments more noticeable soundstage improved and on top of that really nice bass for me as I listen to classical rock or big beat and those bass makes it more pleasant for me. One thing I hate is how in past few years quite a lot more people started to use them and they can't appreciate the music as they are just kids listening to recycled audiosmog king of commercial waste.
If you are concerned about bass being too strong there are some mods that are supposed to deal with it and either bring out the mids and highs or weaken the lows, p.e. Kramer's mod, using HD414 pads.
Some people says they are not portable enough or that the when folded in bag it not practical, on the other hand form my experience I found that while carrying in the small bag is pretty good when packing or travelling and space is an issue, but the most notable advantage is that they are so much more durable when in the bag, because of fragile cable and if you wear the around your neck other than discomfort cable breaks a lot quicker. 
As mentioned comfort is bit of an issue. Forget about them hanging around your neck but if you have either longer or curly hair they will get caught and ripped by them and like once a week and it can be really painful. Also if you are using them for more then 2 hours or so it gets fatiguing and you feel them pressing your skull. It gets a little better when they are worn in but if you plan on using them for longer periods of time I advise you to switch to a light comfort zone and then it's absolutely minty (although they don't hold on your head as firm).
But other than comfort and weak cable Portas are wonderful, they have sweet old school design that really grow on me, also are very lightweight and music experience is sensational, on top of that the are delivered with koss lifetime warranty so they are embarrassingly inexpensive. I have paid for mine and 6 new ones due to warranty about 90 bucks, so there goes the value.
For the final verdict: go and pick yours today or if you are concerned with comfort pick the Koss KSC75 and enjoy the music.
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100+ Head-Fier
Pros: Sound quality, comfort, design, aesthetics, design hasn't changed since '84, uses KSC35 drivers, just in blue instead of black.
Cons: May be considered to be dorky and ugly by the Beats, Soul, Skullcandy, and Bose crowd.
I got a pair of Portapros last month, along with a Sansa Clip+ 4GB, these headphones sound really, really good for $40, especially with an EQ'd Clip+, and I had UR40s, which are also great bang-for-the-buck headphones, sound great, comfortable as can be, however they're not as portable as the Portapros are. Unfortunately, the UR40s died due to a short in the plug a few years ago, so I lived on MDR-V150s and Bass Freqs, both of which are OK for the price, but not as good as the Portapros or UR40s.
On the comfort aspect, the Portas are extremely comfortable, especially on the "Light" setting, and actually a bit more comfortable than my old UR40s and way more comfortable than my V150s or Bass Freqs, V150s get painful after a while, and Bass Freqs just feel weird after a while. As far as aesthetics, I dig the vintage styling vs. a pair of Beats Solos, but others may prefer the styling of the Beats Solos.
To go into more detail on sound, the Portas have plenty of bass while still allowing plenty of mids and highs, and overall sound really sweet, beating both the Bass Freqs and the V150s, and rivaling the UR40s.
Overall these are a great bang for the buck and are quickly becoming my primary headphones, while the V150s and Bassfreqs are going by the wayside. And this is my first review on here so it may not be very good.
PS: may get some KSC35s at some point and stick them in the UR40 housing to see how the Portapro drivers combined with an open-back circumaural enclosure sounds vs. the open-back supra-aural enclosure of the Portapros/Sportapros. And considering the Parts-Express headband mod for KSC75s as well. In addition, the Sportapros are just a cheaper, more modern-looking version of the Portapros that don't have adjustable temporal pads like the Portapros, but can be converted to behind-the-neck, as they use the same drivers as the Portapros.
Best uses: All-purpose, great-sounding set of open-back on-ear headphones in the sub-$50 pricerange, sound great on MP3 players, computers, or home stereos (although an extension cord may come in handy for use with a stereo). Sound great with pretty much every genre.
Ideal audience: people who would rather have a vintage-looking pair of headphones that sound great and only cost $40 than a pair of Beats, Souls, Skullcandies, or Bose headphones. Basically people who value sound quality over looks.
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King of Pangaea

100+ Head-Fier
I bought my first pair of these when they first came out in about 1986 or so and have been using them for portable audio ever since. first with Aiwa Walkman tape players and now iPod Classic 160.  I have gone through a number of them since then, but the great thing about Koss, no matter what you may think of their cans today, is their lifetime warranty.  If the cable shorts out, or they otherwise break, or become unusable, just send them back to Koss with a check for $7.00 and they will fix (maybe replace).  Used to be $5.00.   Check with them for the current repair rate.   I've bought a few more pair, had several repaired by Koss, and been using ever since for portable audio.  Great value, great sound for the bucks.  I've just bought some B&W P5s, so maybe I will have something better to wear outside, maybe not.  Who knows.  A definite bargain.   Currently about $35 on Amazon.
Makiah S
Makiah S
yar, a great sounding can! An I see why ppl LOVE to mod these things! Although didn't fit on my head entirely xD


100+ Head-Fier
Pros: Cheap, great vivid sound
Cons: Fold into a circular shape, rather than a flat one. Might pulls some of your hairs, specially if they are curly due to the metal band.
I picked these up when I was living in Belgium when I was looking for a cheap and durable portable headphone, that wasn't in-ear, and I was certainly not disappointed.
These headphones have almost the same level of clarity as my Grado SR125i but have a considerably more pronounced bass and are, quite simply, a lot of fun to listen to.
The form factor is quite interesting, because rather folding as most portable headphones, the PortaPro bend into a circular shape, around the size of a tennis ball, which makes them a bit inconvenient to carry if you intend on carrying them inside a laptop case.
I've used these headphones while riding a bicycle to work, I've used them while running, while working in public places, and although they are not ideal for all of those situations, they are certainly more than passable, and give you very enjoyable listening experience. Just remember that these headphones do leak sound, so they might not be ideal for commuting.
When I want to go for a walk, and I don't feel like putting the "rubber band" and the DAC around my iPhone, these are the headphones I'll usually grab because I'm certain they'll sound great, regardless of what I plug them to, even though their sound does improve noticeably when you plug them to a DAC.


New Head-Fier
Pros: Surprisingly well balanced SQ for the price but it needs an amp to really sing.
Cons: Speaker cables extremely fragile, especially at connection with drivers. (Sennheiser PX's have same fragility as well).Needs amp to tame the bass.
My third set of these classics due to the weak speaker cable connection to the drivers which breaks if you just think about it! Koss should have addressed this long ago by adapting the, IMHO, much more substantial cable it uses on its extension cable w/volume control. It is not much heavier.
The issue with bass quality can be controlled with an amp which sharpens/tightens the bass response. Doing so really opens up the midrange and treble and widens the soundstage. It gets even better with a DAC in the chain. I use a NuForce Icon uDAC2 with my laptop (running JRiver Media Center 16) and a NuForce Icon Portable with my Sansa Clip+.The DACs sharpen the focus, add depth and air and reveal the detail already in the recording (Assuming its a decent recording in the first place!)
This review also applies to the KSC-75
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Headphoneus Supremus
Pros: Affordable for the sound quality; foldable into a really compact size
Cons: The cloth cable has a tendency to twist while folding the Pro; the open design is not good for noisy/very quiet environs
This is my first 8 hours of my portapros impression (on a intercity bus, in less than ideal environment for an open can. EDIT 1: this was on the day of purchase).
First thing that stands out: separation of a song's different elements. Made me hear more, yet still sounds fun and engaging. Prominent trumpets, horns, cymbals, etc. Those high notes sounds almost intruding in certain parts of a song. Vocals are slightly recessed compared to other elements. Bass is adequate, but not always. Bass guitars and similar sounds (cello, etc.) sounds great, but kick drum, impact bass and the like almost as if its not enough for me, and I'm not a basshead in any way. String instruments sounds gorgeous, prominent in the songs I listened to.
For curiosity's sake, I listened to my SZS playlist, the whole Coldplay - Viva la Vida album, Coldplay - Mylo Xyloto album, Bloc Party - Intimacy, and Bloc Party - Weekend at the City albums. A 30 Seconds to Mars song (The Kill), and a HD video I downloaded of The Piano Guys song called "Jon Schmidt - Michael Meets Mozart".

EDIT 1 (February 10, 2012): Now that I have listened to it more on my E10, I can say that the bass is overpowering, quite boomy and less punchy then I anticipated in the earlier stated environment. The highs are less prominent than I remember on the bus too, but is still adequate enough to be neither a bother or feeling inadequate. Vocals still sounds recessed to my liking.
Also the day before, I was using it on the Metro (subway), and certainly the boosted bass helps it sounds almost not bassy, as outside noise drowns out the bass. Of course, louder noise will drown out everything, but as far as I can hear in moderately loud noise, the boosted bass helps it sounds "balanced" for a lack of a better term and/or experience. I find it quite a similar experience as on the intercity bus.
Still haven't compared it to my CAL! yet.

Now that I have done the quarter mod (where you cut a hole the size of a quarter on the ear cushions), I can say that the problems I had before (slightly boomy bass, recessed mids/vocals and "just-there" highs) are corrected to a degree. Bass is still very prominent, but not boomy, and rumbles deep. Mids and vocals now, to my glee, are forward and prominent, yet not overpowering. And the highs achieved a somewhat more vibrancy than before. 
And I also have compared to my CAL! also. Before and after the quarter mod, I can say that I prefer my PP more than my CAL!. I can't put a finger on why, but my guess is that while the PP are on-ears, the CAL!'s ear cup just exert pressure a little bit too much for prolonged wear, even after a long time stretched on books. Virtually to my inexperienced ears, they are almost the same. I feel that the PP have more deeper bass reach, but as far as I can tell that's it. Will update this after some more time.

EDIT 2 (February 24, 2012): Finally I can agree with the majority who had used this headphone; that they are bassy 'phones. At first to my ears they are not as bassy as people here made out to be, and makes less sense after I did the quarter mod. But then tonight, after a long time of constant use (to the point of neglecting my CAL), I finally hear the bassiness of it. But I think Koss purposefully made them bassy because they are to be used primarily outdoors, where there are a lot of external noise to intrude in. While they do work for low level noise (just walking around, with the occasional cars passing by) and somewhat work for medium level noise (on a bus), that they sound almost balanced, IMO, but for high level noise (in the subway) they are drowned out by the noise. In a relatively quite environment, they are bassy. A bit boomy, not to my liking, but they are for the most part still punchy and delivers deep bass too. Otherwise, my views are still the same. To my chagrin, it's 2 of MUSE albums that showed me the bass.
Compared to my CAL, I can say I like my CAL better, just because the bass aren't as boomy as the PP. Maybe I need to listen to both of those albums again.

EDIT March 5 2012
This may sound crazy, and this may just be some sort of placebo or something, but I just cut open a bit more of the earpad, and the vocals are now a little more recessed now, yet the bass and highs are somehow tighter now. Before the opening I cut out is 19. cm (0.7 inches) I expand the cut to 2.4 cm (0.9 inches).
Now I seem to slightly hate it now. :frowning2:
On the other hand, I have the HD414 pads incoming, so expect something updated by then.

I will update this when I get more time on it and get more familiar to the sound. And I will also be comparing this to my CAL!. If I remember.
This will mostly be final. But if there are anymore revelations and hidden secrets, I will add below. Hope my eclectic impressions help someone made a more informed purchase.
I lied. Now I added a felt ring "acoustic bass lens" after changing the pads to the HD414 pads. I already did the write up on my blog, and I could use some views, so here it is.
I have owned the Porta Pros (25th anniversary LE) and found the bass too boomy.
The PX100 sounds better and more cleaner than these.
It is also more expensive. :wink:
Makiah S
Makiah S
mm I should really try these actually! I have some Old Koss TD 75's they where my first bass head can and they still kick pretty hard! Point being, I have OLD koss cans and I enjoy them <3


100+ Head-Fier
Pros: Lifetime warranty, lightweight
Cons: Slightly overpowering bass, high counterfeit rate
This is a timeless classic, although lately it's been outclassed by others at the same price point. But the main advantage is that the PortaPros are readily available at a local shop for less than the MSRP. However, if the price is too good to be true, it probably is! Be aware that there are counterfeits being sold: http://loveray.blogspot.com/2010/12/how-to-identify-fake-koss-porta-pro.html
As for the sound, expect an above-average amount of loose bass, which smears the other frequencies a bit. Of the KSC35, the KSC75, and the PortaPro, the PortaPro has the most bass because of how the driver is clamped to your ear. This extra bass works when listening to music outside, but in a home environment, a dedicated home headphone is a better match.
The ComfortZone setting is a nice idea, but most people will probably prefer the lightest setting. As a result, it's nothing more than a gimmick. The headband may also snag some hair, so watch out for that. Lastly, the carrying bag barely fits the PortaPro when it's folded, so it's a bit of a hassle to pack it up.
Of course, there's always Koss' lifetime warranty, so they can be abused pretty heavily.
The PortaPros are a good value for the price, but if you want better audio quality and portability, and are willing to pay extra, take a look at the Koss KSC35.
I plan on using their drivers to resurrect my UR40s and maybe give them a warmer sound.


Headphoneus Supremus
Pros: Bass, Comfort, Sound
Cons: Hair Ripping, Short Cord
What can be said about these headphones that has not already been said in the 25+ years they have been in production?
Well, my girlfriend thinks they look silly...  And that for some odd reason makes me love them more.
Out of few phones I currently own, I always find myself reaching for these. 
With the wonderful bass and full bodied sound comes the whole "PortaPro Experience".
- First you try and squeeze them out of the tiny bag that Koss has provided.
- Then you unroll, unhook and unfold them.
- Next comes the pain of adjusting them on your head as they rip hairs out (surprisingly gratifying).
- The plug, that Tiny little plug now gets placed into whatever devise you have waiting for them.
- Finally, the sound, you forget just how wonderful it is almost every time as it hits your ears.  Heaven
Thank you Koss for this gem.
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Headphoneus Supremus
Pros: Punchy bass, great soundstage, light, comfortable fit
Cons: Open design, flimsy feeling, clips yank on hair
Went to buy them at the suggestion of my friends. I could not believe how long this headphone was produced, 24 years and counting!
Would like to talk about the design first. Having a retro style look, it sure looks ugly to me at first, but I loved it when I saw it in person. Perhaps it might turn a few heads around when you wear it outside, but well, who cares? The folding mechanism is quite cool and makes the PortaPro a really portable headphone.
Comfort is amazing, the ComfortZone pads take away pressure from the ears and allow me to wear it hours at a time. The pad is adjustable to different levels of comfort and the headband is adjustable as well. However, my hair catches on the clips easily, which can be slightly irritating.
The sound was great. Bass is very punchy and extends quite deep down the frequency curve. Mids are not overwhelmed by the bass and can stand up on its own. Treble is not sibilant but lacks sparkle. The soundstage is amazing, very immersive. When used in games it provides a very immersive feeling as well.
My friends are all impressed with these headphones and are considering to purchase one as well. Apparently the sound signature fits the general listeners out there and also the comfort is amazing for an open headphone.


New Head-Fier
Pros: Price, Sound, Retro Design
Cons: Bass Boomy and slightly Muddy, You get what You pay for
Fantastic cheap Headphones despite the bass.  However do not expect them to sound as stellar as people rave them to be. The are a great deal for people who like bass heavy heeadphones and dig the design. The adjustable slides pich hair and they leak ALOT of sound. If you like lots of bass, like the quirkey design, and have no money, then go ahead buy 'em.
I have the REOs and love them. I listened to my friends Koss.


New Head-Fier
Pros: Sound, unique style, comfort, price
Cons: Feels cheap, unique style, not very loud
Last week I was looking for some cheap on-ear headphones that fold.  I went to the store and saw a bunch of choices and at first I settled on the Skullcandy Lowriders...big mistake.  They were extremely bassy and the sound was not clean at all.  I took them back, and for a few more dollars I decided on the PortaPros.  The look was not grabbing but their reputation precedes them...so I pulled the trigger.  
When I first fired these bad boys up I wasn't expecting much.  I was greeted with really clean sounding headphones.  The bass is strong but not overpowering, the mids are clear and detailed, and the highs are a little bit on the bright side in the higher frequencies but not harsh.  Overall I was surprised at the sonic performance of these puppies.  I could easily compare the sound of these phones to my bother's Denon AH-D7000's.  
The looks are growing on me, at first I was NOT a fan, but now I think I can dig it.  But the good thing is, I can't see them when I am listening so...  
The build quality seems a little flimsy, I handle them lightly.  On the bright side, if they break, there is a lifetime warranty.    


New Head-Fier
Pros: powerful sound, cheap, signature sound
Cons: slightly muddy bass, hairpulling
I have no time to scribe a full review here - and there's already plenty written about these phones. I've had PortaPro's for years and they've been jacked into pretty much every device capable of outputting through a 3.5mm hole. What is not to like? They can be slightly muddy in the lower bass regions, but otherwise they are quite faithful warm sounding cans. They compare very favorably to much more modern (and much pricier) equivalents... I've had quite a few pairs and well, there is a noticable difference when you buy a new pair... they burn in nicely. If you need a cheap / good quality pair of headphones that don't hurt your pocket when they go wrong, you can't go wrong really.


Pros: lightweight, portable, cool story, retro look
Cons: you porbably won't get past the novetly factor
I was prompted to buy these headphones for two reasons: I had already owned an Electric Avenues PA2V2 amp and Gary has really hyped the synergy between the Koss PortaPros and his amp.
the other reason was a flippant comment from another head-fier about how he preferred his PortaPros to his Grado 325is -- so as a 325is owner i thought "i've got to see if this is true." And let me tell you it's not, i knew this going into it, but i was in spending mood so i figured "what the hell."
Now, as for the merits of this headphone on its own. They do provide a tremendous value, and i'd recommend them if you're looking for a unique looking headphone that won't break the bank; but if you're used to higher fidelity you probably won't use the for anything other than a watch youtube videos while at work.
they do sound muddy, but probably a lot less muddy than any other comparable headphones in their price range.
If you like quirky headphones these will be a great addition to your collection, but if you're looking for a commuting headphones then go with a $100ish closed headphone.


Headphoneus Supremus
Pros: Great audio for the value
Cons: Ugly, large for size, cheapy
I bought these after I bought my Grado SR80i, so comparison will ensue
They say the same drivers as the... Clip on Koss headphone - too lazy to steal them from my mother
But the Koss PP are more bass and are clearer
Good highs
Lacking mids, but there
Good heavy bass, but little muddy
Great for a starter hifi and will give you the "I never heard that before" feeling in your music
Horrible. Seriously
You don't notice the top band, but you have to adjust to your head every time you get them out so long assembly time for every listening.
The band does go from baby to fat head size. And the band does not grab hair as well as others.
It does adjust the pressure but still is a chore to do and keep adjusted
The cable is thin and too short for me, but can be used well.
Plastic is hard and may cut people
the "ipod compatable" jack is stupid. Koss is a suckup
They hardly fold up and I would rather bring my mdr v6's then these because they fold up to the same size
They do have nice pads and adjust for comfort, just a pain to do.
They do not go around the neck well, but can be possible
Overall great for a starter Hifi headphone and will keep you coming back to them as a standard of audio quality. I recommend these to anyone before they buy a more expensive headphone