About the Gauntlet

Frost & Sullivan’s Analyst Gauntlet is a structured program wherein participating vendors and service providers give industry analysts deep dives and demonstrations of their collaboration solution. The analyst then uses the collaboration solution over a period of time and provides candid feedback based on his/her user experience with the specified tool.

About the Pro Headset Market

The professional headset market is expected to grow at a CAGR of 16.3% from 2019 to 2026 in terms of unit shipments, reaching 65.7 million devices sold by the end of the forecast period. Frost & Sullivan predicts the professional headset market will witness robust growth due to the increased popularity of cloud meeting services, remote working and virtual learning practices. PC USB and UCC headset shipment, in particular, is expected to almost triple in 2026 due to the ability to enhance software communications and collaboration experiences.

About EPOS

EPOS is the independent company established upon the former successful joint venture between audio specialist Sennheiser and the leading hearing technology group Demant. Part of the Demant Group and headquartered in Copenhagen, Denmark, EPOS builds on more than 115 years of experience of audio and operates in a global market with offices and partners in more than 60 countries. EPOS’ objective is to deliver high-end audio solutions designed for enterprises and gamers.

During 2020, EPOS co-branded the existing Sennheiser Communications portfolio as EPOS | SENNHEISER and notably invigorated the product line with the introduction of new endpoint categories, new product models, and general product enhancements.

Today, EPOS offers a wide variety of professional headsets, including the ADAPT Series advanced corded and cordless UCC (unified communications and collaboration) models for task-based workers and a vast assortment of corded and cordless multi-connectivity headsets for call-centric users under the IMPACT Series.

About the ADAPT 660

The Connected Work research team at Frost & Sullivan has completed its evaluation of the EPOS ADAPT 660 premium over-the-ear cordless Bluetooth UCC headset with adaptive active noise cancellation (ANC) designed for task-based users.

As opposed to other types of ANC headsets available on the market today (e.g., feed-forward, feedback, and hybrid ANC), adaptive ANC goes a step further by automatically adjusting noise reduction based on the user’s working environment or circumstances (stationary or on-the-go). The technology intelligently picks up changes in surrounding sound frequency and changes noise cancellation levels in real-time to deliver the best possible user experience both indoors and outdoors. The ADAPT 660 headset is one of few enterprise-grade devices that incorporate this advanced functionality, and it does so through EPOS Hybrid Adaptive ANC technology.

The headset also offers advanced voice pick-up powered by EPOS AI, native Alexa voice assistant integration, and advanced sound adjustment via a personalized audio profile. The ADAPT 660 is ideal for professionals that need a high-end audio experience wherever they are—at home, on the go, or in the office. The product is certified for Microsoft Teams and is compatible with all major UCC platforms.

Our EPOS ADAPT 660 rating is specifically awarded in comparison to other premium cordless Bluetooth UCC professional headset products available on the market that offer PC and mobile connectivity.

For a month, we tested the EPOS ADAPT 660 headset on a large number of audio, video and web calls, as well as for music streaming and general concentration. We also tested the product on the go in noisy environments. Our total score for the device is 4.53 out of 5.00 or 90.6% out of 100%, which positions the device as one of the best products in its range. What follows is how Frost & Sullivan generated this score, taking into account the average rating on 10 different criteria.


Rating Analysis
3.85 Criteria: AESTHETICS

The EPOS ADAPT 660 is packaged in a minimalistic cardboard box with a printed quick guide on the inside of the lid, instead of a separate printout, showing the general instructions for management and use of the device. Inside the box are a soft-sided carrying case and a plastic bag containing inserts such as the product Safety Guide and Specifications sheet. The device folds neatly into one side of the carry case on which there is a printed guide of how to fold it to fit tightly inside.

Also included in the carry case is a small mesh pocket containing a USB-A to micro USB charging cable; a 2.5mm to 3.5mm jack; and the EPOS BTD 800 USB-A Bluetooth dongle.

Made primarily from aluminum, leatherette, and plastic, the first impression of the headset is that of a premium device with a modern, stylish look. Upon lifting it, the headset feels very light in comparison to other binaural over-the-ear headsets. Upon touching it, one immediately perceives a high-quality build that is characteristic of the EPOS audio heritage. The headset top clearly demonstrates superior product design and high-quality workmanship. The EPOS Sennheiser logo is placed just over both ear cups.

4.75 Criteria: ERGONOMICS

EPOS ADAPT 660 is powered on and off by simply twisting the ear cups. Left and right markings on the ear cups help to ensure correct orientation on the user’s head.

Soft leatherette material on both the ear cups and headband allow for comfortable wear. The size of the headband can be adjusted up to 37mm on either side. Flexibility in the fit is available both in the ear cups and headband, allowing for less pressure on the head.

One of the main ADAPT 660 competitive differentiators is its weight. At just 227g, the headset has one of the lightest tops in the industry, making the circumaural headset very easy to wear during a full work day without any discomfort.

Unlike other competitive headsets, the form-fitting ADAPT 660 ergonomics do not leave any space or gap between the headband and the head. The rounded ear cups offer flexibility in the fit by adjusting the angle to the natural shape of the head and ears, making the device look sleek when worn, as opposed to bulkier devices.

4.75 Criteria: FEATURES

User Control: The ADAPT 660 right ear cup incorporates a touchpad for swiping and tapping rather than pushing buttons. The user can swipe up/ down to increase/decrease volume and left or right to skip music tracks or mute/unmute the microphone. A single tap controls play/pause media and accepting calls. A double-tap turns TalkThrough on/off and places an active call on hold. A one-second tap rejects or ends calls. A two-second tap activates voice assistants, such as Alexa. A four-second tap alerts the user of the remaining battery power. Once the device is used for a short time, it becomes very easy to use the swipe and tap functionality. Voice prompts are set by default to English. Users can change their voice prompts to German, French, Spanish, Chinese (Mandarin), Japanese, Russian, or Korean.

In addition to the touchpad, the edge of the right ear cup incorporates a series of controls, including the active noise-cancelling (ANC) switch, allowing the ANC to be turned off/on in adaptive mode or maximum mode; a Purple button to invoke the Microsoft Teams client or pair with Bluetooth devices; and a Bluetooth on/off switch positioned at the top front-end of the ear cup. The right ear cup is also where the status lights or LEDs are placed, as well as the micro USB-A port and 2.5 mm audio port.

Connectivity: The ADAPT 660 is a much-advanced version of its predecessor, the Sennheiser MB 660, which offered Bluetooth 4.0 connectivity and limited codec support. The new device uses Bluetooth 5.0 connectivity and includes support for AptXTM, AptXTM low latency, AAC, and SBC audio codecs.

While a direct Bluetooth connection can be established to mobile devices, tablets, and PCs with built-in Bluetooth functionality, the BTD 800 USB Bluetooth dongle ensures both mobile connectivity and better audio quality to computers with a USB-A port. The dongle works with all major operating systems and is plug-and-play.

Bluetooth multi-point connectivity is offered to simultaneously connect to any two Bluetooth devices (e.g., a PC and a mobile device).

A wired connection to a PC is performed with a USB-A to micro USB connector or a 2.5mm to 3.5mm cable.

Security: EPOS minimizes the risk of air attacks of its Bluetooth headsets by deliberately reducing the radio transmission power during the pairing process. This drops the signal to an effective maximum range of approximately 20cm, making interception of the data transmitted during pairing difficult.

UCC Service Integration: The ADAPT 660 is certified with Microsoft Teams, with a dedicated Teams button to launch the software, and is compatible with a wide variety of communications soft clients in the market such as 8×8, 3CX, Alcatel-Lucent Enterprise, Amazon Chime, Avaya, Cisco, Counterpath, Microsoft, Mitel, Unify, and Zoom, among others. EPOS is heavily committed to continuing to broaden its unified communications (UC) support in the market via updated firmware versions.

Others: When the headset is enabled in the Alexa application, users can easily connect to the voice assistant by holding down the touch panel for two seconds (or one audible beep) to easily access the calendar, listen to music, search for news, ask for weather forecasts, and more. Alexa support is, therefore, a productivity enabler.


With the aid of proprietary SpeakFocus technology, the EPOS ADAPT 660 offers three advanced Digital Micro-Electro-Mechanical Systems (MEMs) beamforming microphones with a microphone frequency response of 150 to 6,800 Hz for crystal clear voice transmission.

Optimal speech intelligibility is also achieved via the company’s Advanced Own-Voice Detector technology, while wind noise is greatly reduced with the company’s WindSafe technology for outdoor conversations.

Powered by EPOS AI, the company’s artificial technology that can separate human voices from extraneous sounds, the ADAPT 660 is the first EPOS device that also incorporates machine learning-developed noise-cancelling algorithms that optimize voice pick-up to enhance microphone performance, allowing for a high-quality audio experience. EPOS AI continually monitors the user’s audio environment and instantly adjusts the endpoint microphone settings to the surroundings based on multiple parameters.

When testing the ADAPT 660 in a noisy home office environment, the microphone performed very well to filter out most ambient background noises and enhance audio transmission. The headset is, in fact, one of the top performers among other products in this competitive class. The headset also performed very well outdoors, not only efficiently blocking wind noise but also traffic and other street sounds.


The running time of the EPOS ADAPT 660 is up to 30 hours with ANC on and Bluetooth off, and up to 20 hours with both ANC and Bluetooth enabled. This is comparable to other products in its category. It is to be noted that the exact operating time is influenced by factors such as the audio and background noise volume. A full battery charge from 0% to 100% is achieved after approximately three hours. Standby time is up to 15 days.

The wireless range of the ADAPT 660 is up to 25 meters.


The ADAPT 660 audio quality is above average when compared to competitive products. Leveraging Sennheiser NoiseGard technology, four adaptive ANC microphones monitor the work environment and adjust noise reduction accordingly, while reducing wind noise outdoors when outside.

Via the EPOS Connect application, the user can further adjust the “adaptiveness” levels of noise cancellation to suit the individual preferences and environment. The ADAPT 660 is one of few professional headset products in the market that offer this type of advanced adaptive ANC technology, helping users to stay focused and concentrated, no matter where they work from.

In addition to the adaptive ANC mode, and as previously explained in the “Features” section, the user can also turn ANC off for passive noise cancelling and turn on the “maximum mode” to run the ANC noise reduction at full capacity.

For media listening, on the other hand, EPOS stereo sound delivers a very rich listening experience with the ability to customize the audio profile further via EPOS Connect in four different settings, including Neutral, Speech, Club, Movie, and Director (for manual audio customization).

The headset is equipped with EPOS patented ActiveGard technology that protects headset users from any hearing loss or damage from acoustic shocks and complies with European standards for protection against noise at work.

The dynamic stereo speakers have a size of 40mm and deliver a speaker frequency response of 17 to 23,000Hz, impedance of 46 Ohms, and 118 dB of sensitivity. Total noise attenuation is up to 30 dB.


As with other EPOS headset families, the ADAPT 660 is supported by the intuitive free-of-charge EPOS Connect software. Available for Windows, Mac, iOS, and Android, the software ensures the headset works seamlessly with the majority of softphone clients in the market; provides access to the latest headset firmware updates; and allows users to personalize audio settings, including sound effects, adaptive ANC, call enhancement, sidetone, and voice prompts, tones, and languages.

The ADAPT Connect software also allows users to easily activate Amazon Alexa, verify battery status, and activate/deactivate the Smart Pause functionality.

Both the mobile and desktop EPOS Connect interfaces are intuitive and easy to use to optimize the functionality of the ADAPT 660 headset.

4.00 Criteria: PRICE

The EPOS ADAPT 660 retails for $439 (USD). There are different discounts offered from channel partners or via the Internet, in general that bring the price within the range of similar high-end Bluetooth UCC competitive products. While some buyers may perceive the price as a bit high, the device’s feature functionality and superior product quality are certainly worth the investment.

As with many EPOS products, new ADAPT 660 devices are sold with a 2-year warranty included.

In general, the premium price paid for EPOS products is justified by the company’s well above average technology and quality that assures a product that can last for years.

4.25 Criteria: EASE OF USE

On-boarding for the ADAPT 660 is easy with simple instructions to power the device on/off;  pair it with Bluetooth devices; connect the USB dongle with the headset; use the touch and switch controls; and sync it with the EPOS Connect application.

Becoming familiar with all the functionality the device offers may take some time, however the included quick guide instructions are more than enough to get a user rolling with the standard functionality. If a deeper dive into the product specifications is required, EPOS offers a detailed user guide posted on its website in several languages.

The EPOS ADAPT 660 can be efficiently managed with the cloud-based EPOS Manager software tool that allows administrators to see all of the deployed devices deployed on their network in a single dashboard. The application allows IT departments to efficiently manage and update the firmware of products remotely, centralize configurations, analyze device usage, run reports, and gain additional insights. EPOS Manager supports all popular operating systems, including Windows, MacOS, and Linux.

Analysis Summary

The EPOS ADAPT 660 is one of the most advanced premium over-the-ear cordless Bluetooth UCC headsets in the market today. It is ideal for individuals that prioritize high audio quality for both the transmission and reception sides of audio experiences.

Powered by EPOS AI for superior call clarity, an adaptive active noise-cancelling (ANC) system for noise reduction and stereo sound for high-quality audio reception, the device is full of features and built-in capabilities that elevate the user experience to the next level. A durable and highly transportable product that can work seamlessly at home, on the go, or in the office, the EPOS ADAPT 600 works with all major UCC providers in the market, offering multi-point connectivity to mobile devices and PCs.

A balance between ergonomics, high audio quality, and functionality makes the EPOS ADAPT 660 stand out among other over-the-ear cordless Bluetooth UCC headsets available anywhere today.

Click here to for additional details about the EPOS ADAPT 660.

About Mohamed Alaa Saayed

Alaa Saayed is ICT Industry Director - Digital Transformation, at Frost & Sullivan. He has 20 years of experience in the telecommunications industry in fields such as research, consulting, strategic planning, competitive intelligence, and marketing. He has extensive expertise in the enterprise communications, enterprise endpoint, and unified communications and collaboration markets.

Mohamed Alaa Saayed

Alaa Saayed is ICT Industry Director - Digital Transformation, at Frost & Sullivan. He has 20 years of experience in the telecommunications industry in fields such as research, consulting, strategic planning, competitive intelligence, and marketing. He has extensive expertise in the enterprise communications, enterprise endpoint, and unified communications and collaboration markets.

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