Koss Pro 4AA Headphones Review
Not all legends are good
Koss is an icon in the headphone industry, and deservedly so! I’ve loved basically every Koss product I’ve ever used, from the classic Porta Pro to the stunningly neutral KPH30i to the surprisingly comfy and cheap UR20.
The company has a long history of making excellent and important audio gear. About 50 years ago, they launched the Pro 4AA, a large and rugged set of studio headphones that’s remained on the market for nearly that entire span of time. It started out with fluid-filled ear pads that have since been replaced with foam, and it’s had a few branding and cosmetic updates to bring it line with Koss’s current look…but otherwise the pairs you can buy now carry the same design legacy as the originals.
In theory, headphones should be able to stand the test of time, especially if they can reproduce the entire audible spectrum of sound. Many studio classics endure for decades, from more modern favorites like the M50X to older stalwarts like the MDR V6/7506 and the DT150.
As long as a headphone is still comfortable, durable, and relatively accurate, I don’t care if it was designed before or after my own birth in 1984.
The Koss Pro 4AA’s nail the durable build…and fail so hard at every other important aspect that they’re one of the absolute worst headphones I’ve tested in my years as a reviewer.
Note: I bought this pair of headphones with my own money and wasn’t sponsored or paid by Koss to write this. And their product photographer even got upset at me on Twitter(1 , 2) when I was sharing my early thoughts and struggles. You can read my full review and monetization policy right here.
None of the links in this piece are affiliate links as I don’t believe in the practice.
The Koss Pro 4AA is a closed-back studio headphone with an 8 foot coiled cable that sells for around $80 online, depending on which way the Amazon winds are blowing. You can see its official site here.
Getting them out of the box is the first of many un-fun challenges awaiting you. The coiled cable is sleeved in a plastic bag that’s secured tightly at both ends with copious amounts of tremendously sticky tape, and once you finally get it free you’ll almost certainly have to remove some adhesive from the cable itself. Pour one out for all the college production interns out there who have ever had to try and quickly take one of these out of the package.
Unlike other still-produced classics like the Beyerdynamic DT150, the plug end here hasn’t been updated with a 3.5mm jack. Instead, it uses a 6.3mm plug with no adapter included. The headphone has a 250 ohm resistance and it’s a bit hard to drive, so I assume they’re still making this to plug into an audio production console, but a plug update or removable cable option would have been nice to better compete in today’s world.
I normally do sound quality first, but the beefy build of the Pro 4AA is its most impressive characteristic. The headband is a single piece of solid molded rubberized plastic, with a metal framework for reinforcement and metal forks for the cups. The design has an iconic aviation-style look that would look beautiful in any collection. And at a mass of 550ish grams, it’s such a tank that it feels like it’ll be around for millions of years.
ZeosPantera, famous headphone reviewer of Youtube, once said you could swing these around on a rope and break windows with them in a junkyard, and that’s too apt and perfect for me not to repeat and link here.
This is an absurdly well-built thing for the price, and stands tall build-wise against just about any other headphone on the market. The adjustment sliders are friction mounted, and take a significant amount of force to push in and out. There’s not a hint of creaking or wobbling present anywhere in the frame. Even the outdated microphone mount point is a robust piece of solid metal.
Nothing else about these headphones is good or worth your time or money.
Pain. Extreme pain. Clamp, weight, and instant nightmare ear death. All these things and more can be yours if you decide to wear the Koss Pro 4AA headphones.
The second you put on these nearly 20 ounce beasts, they jam so hard into your ears you’ll want to throw them into the nearest garbage can. The pads seem like they’ll be soft enough, and indeed, the rubberized coating on them has a light and smooth feel to it. But the area in the center of the pad is a sharp plastic mesh like that found on the back of a baseball cap.
Thanks to a severe lack of foam, that evil mesh presses right into your entire ear with the force of a thousand burly arms, and when combined with the overall weight of the headphones and the sharp plastic wall behind the mesh, these simply aren’t wearable.
I have no idea how these ever got through testing, whether in the 70’s or in the halls of Koss today. They’re the most clampy, most uncomfortable headphones I’ve ever worn in 37 years of living, and the robust headband piece means they aren’t even that easy to stretch out. And even if you do stretch them a bit, you still have to deal with the weight and the nightmare mesh inside the pads.
The insane clamp is part of the design here to help with isolation…and they do isolate well. But they’re so wildly uncomfortable that on the first day I couldn’t listen to more than one song without hating myself. On day two of testing, I could get up to about 25 minutes but I still wondered where my life went wrong.
Maybe things were better with the original fluid-filled pads, but those aren’t easy to come by anymore and not the default way these are currently sold, and I don’t review headphones in non-stock configurations.
What makes this terrible comfort all the more frustrating for me is that the headband padding is actually brilliant. It’s a huge thick piece of foam that’s just as solid and amazing as the rest of the build of the headphone, and it does a brilliant job of balancing the heaviest headphone I’ve worn since the Blue Mo-Fi across the whole width of my head.
With completely revised ear pads that actually had some room for human ears and didn’t just try to cut them like a cheese grater with a hard plastic mesh, these might be salvaged…but again, I think these specific thin pads and the harsh clamp are both core to the design and the sound.
After a few days with these, I felt silly for ever complaining about the small comfort issues on the AKG K371BT. The Pro 4AA sets the lowest possible bar for comfort, then lowers it further, all while somehow having an amazing headband pad.
If the sound were excellent here, I could almost understand why people are still buying these. But they sound at best unremarkable, especially compared to the truly terrific Koss products mentioned in the top lines of this review. The KPH30i still has perhaps the best dollar-to-sound-quality ratio of any single audio product on the market today.
In contrast, the Pro 4AA has a decently accurate midrange with slightly rolled off highs and almost no power in the low end to speak of. And that’s about it. If I had to render the word “meh” as audio quality, it would sound like this. There’s no real soundstage width here either.
It’s hard to enjoy what merit the smooth midrange has because you’ll just be wondering if your ear cartilage is taking permanent damage from the clamp and the mesh.
Please don’t buy these unless you want to have something that looks nice on your shelf of retro items, or you just really enjoy feeling heavy items with your hands. As someone that likes touching DT770’s, I can relate to that a little bit.
If you’re looking for a studio headphone, buy literally any other popular studio headphone from the last few decades. It’ll fit better and sound better, and it might even have a removable cable too.
If you’re looking for a Koss product, buy literally any other Koss product. They make so many excellent pairs of headphones, and they’re all more worthy of your time and money than this particular model.
I love the design, build, and headband pad on the Pro 4AA…but they’re unwearable for more than about a half hour, and they don’t have near enough sound performance to compete in today’s $99 studio headphone market. This is the most disappointing headphone that Koss currently makes, and the most disappointing headphone I’ve used in many years.