Koss PRO-4, PRO-4A and Pro/4 AAA Plus headphones Headphone Buying Tips

Sidebar 1: Headphone Buying Tips

When auditioning headphones, take along a wide variety of program material. Try to include recordings that use different miking techniques (pan-potting, Blumlein, ORTF, etc.) The ear and brain hear headphones differently from speakers, which changes the way you perceive colorations.

What you hear depends not only on the hardware and software, but also on what's going on inside your head. Don't listen unless you're rested and relaxed. Start by auditioning one of the better 'phones (Class A, B, or top of C in Stereophile's "Recommended Components."). If it doesn't sound right, it might be a good idea to listen at another time.

"Hit and run" listening is usually better than extended listening for catching colorations. The brain does an excellent job of canceling vowel colorations; long listening sessions can produce a total subjective null. (With mild colorations, a full null can occur in 10 to 15 seconds!)

Once the colorations are nulled, the opposite colorations are then superimposed on the sound of the next headphones you audition. This is similar to the complementary afterimages produced when you stare at a brightly colored object, then look at a white surface. You should take a 10- or 15-minute break after extended listening to one pair of headphones. I always do—and stick in earplugs.

More expensive" is no guarantor of "better." Judge only by what you hear, never by the price tag. !S Most headphones are comfortable on most people. But there are exceptions. Once you've found a pair whose sound you like, wear them at least five minutes to see if they pinch your ears, squash your flat top, or make any part of your anatomy sweaty or uncomfortable. If you wear glasses while listening, be sure the headband doesn't crush the eyeglass temples against your head.

Most personal stereos have significant output impedances—from 5 to 40 ohms, and sometimes as high as 100 ohms! (Your power amp's output impedance is close to zero.) This impedance can interact with variations in the headphone's impedance to color the sound. Listen to all the equipment you intend to use your headphones with to make sure their sound is okay on each.

All earpads slowly deteriorate. Foam pads can disintegrate with just a few months of regular use. Vinyl-covered pads can last several years, especially when treated with (snicker) Armor All and cleaned with a suitable vinyl cleaner, such as Tuff Stuff. If you consider your headphones a lasting investment, check on the price of replacement pads. They can be startlingly expensive.

Some headphones vary in response as you move them around on your ear. If the headphones won't stay comfortably in the best-sounding position, you don't want them.

Headphones—especially electrostatic and orthodynamic models—usually need to be thoroughly broken-in before they sound their best. Try to audition a well-used pair—and don't forget to break in the new pair you buy.

Since most headphones sit close to the ear, the pinna does not induce the colorations it would if the sound came from a distant source (such as an orchestra or loudspeaker). The better headphones are equalized to compensate for this effect. However, pinna colorations—not to be confused with pina coladas—vary with the size and shape of the ear. My ears are very average, so most readers can assume they will hear what I did. If your ears are unusually large or small, or have an odd shape, you may find that headphones sound different to you than they do to your friends with normal, decent ears.—Bill Sommerwerck

Koss Corporation
4129 N. Port Washington Ave.
Milwaukee, WI 53212
(414) 964-5000

dc_bruce's picture

were Koss Pro 4A's which I bought in 1968 or '69. They were a bit bass heavy and not particularly transparent. I replaced them a few years later with Sennheisers, which were lighter and far more comfortable. They also sounded better, albeit with less powerful bass. In 1971, I acquired a pair of used Stanton electrostatics, which were a revelation in transparency although lacking a bit in bass "thump." After a year or two they failed, and I never went back to headphones again.

I believe Koss gets credit for being the first to actually develop purpose-designed headphone drivers. It is sad that the company, after such a strong start, "lost the plot" so badly. They are still in business, I believe. One of their other problems was an accounting scandal a few years ago (the company's stock is/was publicly traded) which resulted in a wholesale clean-out of the executive suite. Sad to see this happen, especially when headphones have become a fashion accessory (Beats) as well as an audiophile "thing."

Bogolu Haranath's picture

Try Audeze LCD-1, $399, reviewed by Inner/Fidelity and Hi-Fi News ...... Easy to drive 13 Ohm impedance :-) ......

PAR's picture

You can't compare the Audeze LCD-1 with these Koss cans. The Audeze is current, these Koss reviews date from between 1963 and 1991 and the featured headphones haven't been manufactured for decades.

Bogolu Haranath's picture

Yes, I know ...... I was responding to dc_bruce's comments above ....... LCD-1s are in the same price range as some of the top model Beats headphones ...... LCD-1s are better quality for about the same price :-) ......

Metalhead's picture

Definitely a rite of passage as I was one of the folks moving from cheese-o to fancy Koss Pro 4AA headphones in 72. I think they were double A's but never saw that listed so maybe I may be the unreliable narrator. I did not have a mic connector and pretty sure I remember that correctly.

Enjoyed them but not too worried about quality as they were just playing Tull, Beatles, Zep and Floyd. I did move up to the first Koss electostatic phones and they were fantastic. Koss ESP-1 (think that was the model).

In any event LOVE the J. Gordon review where he calls out a set of Koss as being a dog and it is just refreshing to read a one or two sentence pan without the current three paragraphs or more of wrangling a redeeming feature out a component or piece in for a review.

Don't use headphones any more but appreciate you posting a blast from the past.

tonykaz's picture

They still sell on eBay for between $25 and $150. ( $11 Shipping )

I've owned two of these and remember them to be heavy, uncomfortably hot, awkward and replaced as soon as ANYTHING better came along. I've seen these things in a good many Audiophile's homes ( mostly unused ).

There wasn't much in headphones until Sennheiser came along. So people would have the Pro-4 or seek out the STAX ( that I carrried but were far too expensive ).

Seeing the KOSS photo reminds me of how incredibly far we've come.

Tony in Venice

ps. they were made in Wisconsin, my origin home, ( not chinesium ) so they seem to survive rather well and are not being thrown abandoned into another Waste Management Land Fill filler.

mrounds's picture

I bought a set of Pro/4AA (yes, double-A; sound is much like the original Pro/4A as reviewed) in college. Cans were necessary in the dorm, especially cans with the gel surrounds.

They were (and still are) heavy and uncomfortable for long sessions. Sounded much better than the 6" San Franciscan (Goodmans) speakers on my dorm stereo. A tad boomy, and somewhat rolled off in the treble, but that's what tone controls and a switch to turn off loudness compensation are for. The EPI 100 speakers I got after college (and still have) are far more neutral sounding.

The original set finally died - wiring problems - in the early '90s. Koss had never been very good about advertising their lifetime warranty, so I bought another Pro/4AA from Radio Shack - exactly like the original after about 20 years. Still have them. They work well when listening to stuff from the computer in the wee hours. They again developed a wiring problem about 10 years ago; sent them back, and Koss fixed them for free (except for the cost of shipping them there).

Yes, there are far better phones now, especially if the budget is unlimited, but these are here, and they work. Pretty well, actually.

otaku's picture

Yes, I ran out and bought a set after listening to them in the listening room at our college student lounge (anyone remember listening rooms?). After I drove two hours in the rain to go buy a set, my poor Dad had to make the same trip to get a set for my brother. I had them for probably 15 years, finally gave up fixing them.

Ortofan's picture

... the choice of Pete Campbell on the TV series Mad Men.



deckeda's picture

The air from the headband "squares" emptied, the air from the ear pads did the same (replaced them once) and I don't ever recall the sound as anything special. But they were my first. I was always interested in hearing the HV/1A and thought that style was the future. And in a way, it has been (for pretty much everyone else.)

I liked the tension adjustment innovation for the PortaPro, but never appreciated the "good sound" they were supposedly known for.

In subsequent years it was Grado for me, and modernity.