Product Review: Koss CS300 USB Headset

We know from experience that conference calls tend to be longer that normal phone calls. Meetings often require hands free to attend to other matters, making a good headset a valuable tool. Further, interpreters using our multilingual conferencing must use a headset. Our effort to support interpreters using ZipDX includes maintaining a list of recommended headsets.

About a year ago we tried the Koss GMR Series, which are larger over-the ear headsets. Recently, Prof. Barry Slaughter-Olsen of MIIS recommended we try the newer Koss CS300, a USB headset that some of his students have been using as they learn the art of interpretation.

koss CS300 headset

Design & Comfort

Where the Koss GMR-540s I reviewed last year are big, old head-huggers, the CS300 are a lighter, supra-aural design. They rest gently on-the-ear, rather than surrounding it completely. The earpads are cloth covered, as are a trio of cushions across the inside of the headband. They’re comfortable to wear for hours at a time.

The microphone boom pivots around the left earpiece for up/down adjustment. The boom is a pliable plastic allow distance to the mouth to be adjusted easily.


The CS300 has an 8-foot cord that terminates in a USB connector. The cord is permanently attached. There are no controls on the cord or the USB interface. This is ideal, since inline volume or mute controls are seldom used, and tend to be physically awkward.


While we’ve only had the CS300 for a couple of weeks, it appears to be robust. It’s certainly comparable to the call-center headsets that we have recommended in the past.

Unlike those professional products, you won’t find Koss offering replacement earpads or cushions for the CS300. That’s ok, since the CS300 sells for around $50, which is less than most call-center headsets. By the time you eventually wore out the ear pads, you could likely justify buying a new headset. Then again, Koss offers a limited lifetime warranty.

koss CS300 headset on a guy


Earpieces – Hearing Well

The larger GMR-540 is truly a music grade headset that happened to have a microphone. It easily outpaced any of the call center headsets that we have typically recommend.

The CS300 sounds good, very good in fact. It sounds every bit as good as any call center headset, but its smaller drivers cannot match those of its larger brethren. Nonetheless, for our purposes here at ZipDX, which is fundamentally about delivering voice clarity, the CS300 is excellent.

Microphone – Being Heard Clearly

The boom-mounted microphone features a noise-cancelling electret condenser element. The mic element is located at the tip of the boom, which has 3/8” long slotted openings front and back. Koss claims that the microphone passes 100 Hz to 16 KHz. This meets the latest AIIC guidelines for distance interpretation. We verified that claim with a test & measurement process.

We were particularly impressed with the noise cancelling behavior of the microphone. Voice sounds clear and natural, while ambient noise is substantially avoided.

USB Connectivity

We like to recommend USB headsets to interpreters. USB headsets are simple; easy to connect to the computer, and have few, if any, settings to be adjusted.

When connected to a computer a USB headset is automatically recognized by the operating system and made available for use. Often the new device is clearly identified by name, which makes it very easy to pick the correct microphone in the ZipDX web phone (pictured below.)

In the case of the Koss CS300, they are indicated as a generic “USB audio device” as pictured here. This is a little less obvious, but not a deal breaker.

Full-Duplex Operation

In the course of a review we always test USB headsets to ensure high-quality, “full-duplex operation.”

In normal conversation people are seldom both listening and speaking at the same time. Conference interpreters are an exception. They are continuously listening while speaking. Thus for an interpreter, it’s critical that the sound is perfect, in both directions, at the same time.

Unfortunately, some common USB headsets degrade the sound from the microphone when there is also sound playing in the earpieces. This fact is why we started to maintain a list of headsets recommended for interpreters.

I’m pleased to report the Koss CS300 passes our most rigorous test. We used the microphone to record some conversation at typical volume, while playing an unrelated, prerecorded message to the headphones. Under such circumstances the sound from the microphone remained clean and clear.


Like their larger brethren before them, the Koss CS300 works very well for our purposes here at ZipDX. Moreover, they are one of the most affordable models we’ve found. That makes them a good choice for anyone who needs the hands-free convenience a headset delivers. We’ve added them to our list of headsets recommended for interpreters using our multilingual service.


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