Cobalt Bluetooth Wireless Audio + Cellphone Headphones

Cobalt Bluetooth Wireless Audio+Cellphone Headphones
Koss Corporation

Price: $299 US

You’re either going to love Cobalt behind-ear Bluetooth premium headphones or you won’t. There is no maybe with this innovative, ingenious product. Audio quality is first-rate, wireless technology is almost effortlessly efficient, guarantee is forever, and placement on your head is – totally up for grabs. Every aspect of these ‘phones is top-notch, but, as stated above, either you are a behind-ear headphone person or you aren’t. I am.

Does Cobalt satisfy this reviewer? Read on. And familiarize yourself with Cobalt’s web site by clicking and snooping around its many links. A summary and ordering page is here.

Koss provides three ways to connect to your Bluetooth (BT) source device: USB dongle, audio mini-plug transmitter, and native BT wireless pairing. Up to eight hours of lithium ion rechargeable battery cycle duration is possible. recommends you recharge this and most other similar batteries when they have between 30 and 50 percent charge remaining.

Included accessories are generous. Koss states, “The Cobalt package includes the stereophone, audio transmitter, USB audio dongle, USB charging cable, AC charging adapter, and audio extension cable. Transmitter requires (2) AAA batteries that are not included.”

Why no batteries? Koss tells

1) Past experience has directed us not to include batteries due to stocking issues and time frame that could potentially go beyond the battery life.

Cobalt has a convenient folding configuration for travel. What about providing a carrying or protective case?

2) We do sell separate cases on our website.

What is the optimum orientation of Cobalt on your cranium?

3) The picture which is included in the general usage instructions is the typical position or view of the stereophone when worn.

How does their Bluetooth transmission operate?

4) The BT computer transmitter is digital. The iPod transmitter converts analog to the BT signal. suggests you set Cobalt’s volume control fairly high, and adjust your listening level on your source device, such as Mac laptop or iPod. I had more success using Koss’ custom USB dongle for computer-to-headphone playback then with Apple’s built-in BT (see below). Your mileage may vary, depending upon your individual computer, but the Koss USB device is a winner, almost instantly.

Up/down tiny-arrow volume controls on Cobalt are at the top of its left earpiece, when wearing the headphones, adjacent to a small Mute button. During your first few weeks using these ‘phones, you’ll make a bunch of mistakes attempting to operate the three small controls, and eventually you will be able to configure them without any fuss.

Loudest possible volume on this stereophone can be dangerous to your hearing, so please listen with caution and common sense. I’m wearing Cobalt now as I write. Sound is intense from J. S. Bach’s “Toccata and Fugue in D-minor,” and it’s difficult to concentrate on typing, or hear the different music playing twenty feet away on the living room stereo, even with my PowerBook’s iTunes volume level only one-third up. Behind-ear placement is fine, but I have to tilt my glasses upward so Cobalt doesn’t press them into my temples. Nothing serious.

I’ll have to check with Koss tech support, because audio frequency response when listening to computer playback via either USB dongle or built-in BT is dramatically inferior to audio-plug transmission from my iPod. Just a sec, and I’ll confirm that. Be right back. . . Yes, it’s true. Audio quality is really good via battery-powered transmitter from iPod, and much less so via USB dongle from computer. Stay tuned for a clarification on this glitch.

Hold everything! I figured it out. When I tested Cobalt using PowerBook’s internal BT, it messed up Koss dongle’s ability to send finest audio to the ‘phones. Don’t ask me to explain it further, but please do NOT attempt to listen to these headphones from your computer unless you are using the included USB dongle transmitter. I determined this by listening to Cobalt via USB Bluetooth dongle on my wife’s G4 iBook and on my G5 tower, both of which produced highest fidelity and not the dull sound coming from my PowerBook. I’ll investigate further, and post any fixes below, in our Article Discussion area, or in a future blog. Whew. That was bizarre, and consumed an entire evening to troubleshoot.

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Quick note about batteries: get a charger and four or more AAA rechargeable batteries that you keep fully charged. This way you always have fresh juice for Cobalt’s plug-in audio BT transmitter and help preserve our precious natural resources at the same time.

Quicker note about noise isolation: Cobalt doesn’t provide it. Foam speaker pads rest on your ears, meaning you can hear some ambient sound, and people in the room with you notice a tiny bit of what is playing.

Longer note about Koss Corporation: I purchased Koss Pro4A large, heavy, ugly, expensive, wonderful over-ear headphones in 1968, and used them during ten years of recording, engineering, listening, and travel. I think I gave them to a friend (stupid mistake), but I don’t remember the circumstances. I wish I still had them, like my first Schwinn bicycle or Mickey Mantle baseball glove. You can read about these stereophones by doing a Google search for “Koss Pro4A” (quotation marks not necessary). In 1968, Koss was the first and last word in headphones, and they’ve been a terrific single-purpose company before and ever since. presents a wide range of headphones and earphones, and is pleased that Cobalt, a new-technology product, is our initial evaluation of Koss’ latest and greatest. This company has been in existence longer than most of you have been alive, and is still a family-owned business in unglamorous Milwaukee, Wisconsin. I’ve heard a lot of music since 1968 on speakers and headphones. Acoustical and audio engineering advances are challenges for Koss and their competitors. Do we really need more headphone companies and classes of product? Koss says yes, and stands behind Cobalt with “Koss’ No*Questions*Asked Lifetime Warranty – the only warranty of its kind in the stereophone industry.” How does that sound to you?

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Once we agree that Cobalt’s comfort and BT capabilities are beyond criticism, only three questions remain:

A. How does the audio compare to other Bluetooth wireless headphones?
B. How does the audio compare to other similar premium wired headphones?
C. How well does the cellular phone BT transmission work?

A. Cobalt is the best wireless BT headphone system we’ve tested or heard at Nothing else is even in second place. Feature for feature and audio against audio, Cobalt is tops. That was easy!

B. Grado Labs’ SR 225, reviewed here delivers superior clarity and frequency response for less money and more weight and size, plus a substantial cable. The sound-spectrum curve of Cobalt is concentrated in the melody-rich midrange, with a hefty bass and pleasant treble falloff. “It depends” is an acceptable answer to question B, because the majority of the music I tested on Grado versus Cobalt sounded perfectly fine in a typical wireless listening situation on the Koss stereophones. When the recording was inferior, sometimes the flaws were more annoying on SR 225 and other times on Cobalt. When the recording was of good-to-excellent quality, Grado’s impeccable full-spectrum speaker drivers left no doubt, but the midrange bias on Cobalt was just as often equally pleasant.

C. (Give me a minute to test Cobalt and my Motorola RAZR mobile phone. Hang on, please.)

Wow, that was a snap. I followed brief written instructions from Koss and Motorola, and in a couple of rings I was speaking wirelessly to David Weeks via Bluetooth. I could hear him just fine (rating: 4 out of 5) and he said my voice was a little faint and somewhat scratchy (rating 3.5 out of 5), but otherwise fully audible. Cobalt’s microphone is far from a user’s mouth, so that’s not bad at all. Nicely done, Koss.

Cobalt wireless Bluetooth stereophones are expensive and worth the price if you value all the features included, and the effortless connections. This is a new class of audio/phone product, and applauds Koss for delivering ease of use and versatility on top of clever engineering. The more I use Cobalt the more I’m comfortable with the unit’s behind-ear wearing location. We are pleased to recommend and rate Cobalt at 4 out of 5.


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