Review: EPOS ADAPT 660 – Work Wherever, Whenever

The EPOS ADAPT 660 are designed for both audio listening and communication.
The EPOS ADAPT 660 are designed for both audio listening and communication.

Thanks to the comfortable fit, high-quality ANC, and excellent microphones, the EPOS ADAPT 660 are equally suitable for online meetings, music listening, or travel.

Thank you to Alyssa Ng and Alex Lim from EPOS for providing the ADAPT 660 wireless headphones for review purposes.

The EPOS ADAPT 660 wireless headphones are a pair of flagship wireless headphones with outstanding active noise cancellation (ANC) primarily intended for those who require better microphone quality for calls. Partnered with Sennheiser, the Adapt 660 have an almost identical appearance and build quality as the PXC550-II from Sennheiser.

Aside from the excellent noise-canceling ability, the sound quality of this device makes any genre of music sound good - or at least the way it was intended to sound.
Bottom Line

At the end of the day, the EPOS ADAPT 660 sound like they look: sensible, expensive, and mature. Those who enjoy a clean and transparent sound signature with a bright profile will find much to like with the 660. The ADAPT 660 offer incredible value. However, they have some limitations. Perhaps the most notable is the dated micro-USB port, although it does not affect the overall performance. Additionally, the treble can be a touch bright and I also wish that the EQ settings were less limited in the app.

What We Like
  • Effective active noise cancellation
  • Excellent clarity
  • Precise and accurate bass performance
  • Transparent and clean midrange
  • USB transmitter dongle for more stable connection on PC
  • Dedicated Microsoft Teams button
What We Don't Like
  • Bright sound signature could be fatiguing for those who have a lower tolerance to treble
  • Outdated micro-USB port
  • Limited EQ liberty in EPOS Connect app

The ADAPT 660 have a unique feature set including an exclusive button that launches Microsoft Teams. Powered by EPOS AI, the headphones can adapt to speech and they study the surrounding environment through machine learning.

As a result, the ADAPT 660 are an excellent candidate for both audio listening and online meetings.

In this article, I will test how the ADAPT 660 perform in various conditions and environments.

Company Introduction

EPOS was formed by a successful partnership between the audio-specialist Sennheiser and the world-renowned hearing technology company Demant.

The Demant Group, headquartered in Copenhagen, Denmark, has owned EPOS since November 2009. Leveraging on experience from Demant, EPOS has over 115 years of audio expertise and operates globally with offices and partners in more than 60 countries.

In addition to self-branded premium audio and video solutions, EPOS also sells co-branded “EPOS I SENNHEISER” products via a trade license agreement with Sennheiser. EPOS offers premium audio and video solutions to help individuals and teams attain their goals and perform better.

Technical Specifications

  • Form: Closed-back wireless headphones
  • Drivers: Dynamic driver
  • Impedance (Ohm): 490 ohms (active) / 46 ohms (passive)
  • Sensitivity (dB): 118 dB
  • Frequency Response (Hz): 17 – 23,000 Hz
  • Removable Cable: Y
  • Source Jack: 3.5mm TRRS unbalanced jack integrated with microphone
  • Cup/Shell Jack: 2.5mm
  • Mic: Y
  • Microphone Type: Digital MEMs beamforming microphone (3 microphones)
  • Microphone Frequency Response: 150 – 6,800Hz
  • Noise Cancellation Microphone Type: Hybrid adaptive ANC technology with four microphones
  • Weight (g): 227g

Packaging

The ADAPT 660 come in a simple brown cardboard box printed with minimum information. Opening the box, the ADAPT 660 sit in the case, together with the accessories.

The ADAPT 660 come in a simple box.
The ADAPT 660 come in a simple box.

In the box

  • EPOS ADAPT 660 headphones
  • Stock cable with 2.5mm to 3.5mm TRRS unbalanced plug with microphone
  • Airline adapter
  • Carrying case
  • Micro-USB to USB-A charging cable
  • Manual

There is a decent hard case included with the ADAPT 660 that features a zipper closure that should protect the headphones from scratches, dust, and minor exposure to water. Nevertheless, the headphones are still susceptible to crushing.

The case caters sufficient space for ADAPT 660's storage.
The case caters sufficient space for ADAPT 660’s storage.

Cable

For devices with headphone ports, you can use the EPOS ADAPT 660 with the 2.5mm to 3.5mm TRRS cable included. Using their micro-USB to USB-A cable, they can receive audio and provide charging when plugged into a computer with a USB-A port.

The cables are designed to be simple, with the same design scheme as the ADAPT 660.
The cables are designed to be simple, with the same design scheme as the ADAPT 660.

Design

The ADAPT 660 are over-ear headphones with a reasonably understated appearance in terms of design. They appear identical to the Sennheiser PXC 550-II Wireless, although now they have a combined EPOS logo together with the Sennheiser logo. The high-quality materials used in their construction give them a premium, high-end appearance.

Black in color, the ADAPT 660 feature a matte finish with leatherette accents on the headband and the circumaural (over-the-ear) ear cups. Touch-sensitive controls are located on the outer panels of the cups, although you can not notice them, as the panels are blank.

The ADAPT 660 headphones exhibit excellent build quality and are pretty solid in appearance. Moreover, they have a thick plastic headband reinforced by a thin metal frame. In general, they should be able to withstand a few accidental drops and bumps without suffering too much damage.

Despite being over-ear headphones that I generally find less comfortable than on-ear headphones or IEMs, the ADAPT 660 are quite comfortable to wear. The oval-shaped ear cups are relatively small but should be large enough to fit most people and provide a good amount of passive noise isolation due to their tight, secure fit.

They have the same great padding as the Sennheiser PXC 550-II. However, due to the headband’s limited extension, even though heavily cushioned and comfortable, these headphones may not suit all head shapes and sizes.

The EPOS ADAPT 660 are reasonably portable. As with most over-ear headphones, they take up space in your bag, but you can fold them into a more compact form to save space or swivel the ear cups flat for more comfortable wearing around your neck.

I describe the design scheme of ADAPT 660 as gentleman scheme - luxurious and mature.
I describe the design scheme of ADAPT 660 as gentleman scheme – luxurious and mature.

Controls

The touch controls located on the ear cup are intuitive and responsive. You can play or pause music by tapping the right ear’s outer panel. You can skip tracks by sliding forward or backward, and you can change the volume by sliding up or down.

You can also accept or reject calls by holding your finger down for a second and tapping twice to place them on hold.

In a call, the microphone is muted or unmuted by moving forward or backward. By double-tapping the headphones, you can disable ANC and muffle the music, and put them into Transparent Hearing mode, during which the ambient mics pick up your voice and your surroundings so that you can talk with ease.

The control panel is embedded on right faceplate, which enables various kind of control on ear.
The control panel is embedded on right faceplate, which enables various kind of control on ear.

Microsoft Teams

Unlike the Sennheiser PXC 550-II, the EPOS 660 come with a dedicated Microsoft Teams button. When the headphones are connected to your device with Microsoft Teams installed, the Teams window can be triggered when the button is pressed.

This feature is astonishingly helpful for those users who rely heavily on Microsoft Teams in their work (including me). I used to struggle to find the Microsoft Team in the sea of windows on my desktop. Now I can quickly bring Teams forward with just a button press.

The purple Teams button differentiate the ADAPT 660 from the PXC 500-II.
The purple Teams button differentiate the ADAPT 660 from the PXC 500-II.

Smartphone Application

The EPOS Control app is worthwhile to download if you want access to firmware updates, provided you are comfortable with the app having access to your location.

You cannot use the app without granting location permissions.

Even though this may seem alarming, it is required for all headset companion applications to locate the headset. In addition to firmware updates, the app also allows the user to choose between adaptive and anti-wind noise cancellation.

Additionally, you can choose from four preset EQ settings (Neutral, Club, Movie, and Speech) or create your own. However, the EQ adjustments are minimal: you have only three choices for each adjustment under vaguely labeled options (Boost, Spatial, Reverb, and DLC).

If you find the EPOS app too limited, you may wish to consider alternative applications to adjust EQ on your phone more precisely.

Although the app does not explicitly mention it, DLC stands for Dynamic Loudness Control. Dynamic loudness control aims to boost low and high frequencies when listening at quiet volumes to make it appear as if the sound pressure level is flat.

You can toggle effects such as smart pause and call enhancement within the settings options. Upon removing and reinserting the headset, smart pause automatically interrupts and resumes playback.

The EPOS Connect smartphone application allows users to customize options, such as toggling noise cancellation level.
The EPOS Connect smartphone application allows users to customize options, such as toggling noise cancellation level.

Internals

The driver size is not specified on EPOS’s official website, but I believe they use the same 32mm dynamic driver as in the PXC 550-II. The driver is angled in the ear cup to provide the best audio transmission angle to the users’ ears.

Active Noise Cancellation

The EPOS 660 are one of the best flagship noise-canceling headphones and the highest setting ANC can effectively suppress low-frequency noise.

While reviewing the EPOS 660, there was a construction project near my apartment, and I found the ADAPT 660 can eliminate drilling noise, although some vibration noise is still audible to me. Overall, the noise cancellation serves me well during this disastrous period.

In general, the headphones’ passive isolation primarily attenuates upper-midrange frequency noise. ANC must perform less work the more effectively your headphones isolate.

You must ensure that the headphones are fitted correctly to achieve optimal noise-cancellation. The ear cups should fully encircle your ears, avoiding any gap behind the ear where the lobe meets the jawbone. EPOS seems to understand the importance of passive isolation with the 660’s spacious, ergonomic ear cups.

The ear cups are specially designed to provide best isolation that further enhance the overall noise cancellation.
The ear cups are specially designed to provide best isolation that further enhance the overall noise cancellation.

Connectivity

The ADAPT 660 support various high-quality Bluetooth protocols, including SBC, aptX, aptX Low Latency, and AAC. AptX Low Latency is excellent for Android users who play mobile games and wish to hear the sound in real-time; it is also beneficial for video streaming.

There is always the option of listening to music via a wired connection if you do not wish to deal with the Bluetooth codec alphabet game. As indicated above, EPOS provides users with a 2.5mm cable that terminates in a standard 3.5mm headphone plug for lossless audio playback.

Despite the 2.5mm input being an unusual choice, it saves space internally for advanced ANC components and multiple microphones.

Besides all these typical connections, the ADAPT 660 come with a USB dongle for 2.4GHz signal transmission. This connection method is commonly found in gaming headphones which require a wireless connection that is more stable than Bluetooth. EPOS implements this connection to the ADAPT 660 to ensure stable connectivity to users’ devices during meetings and conference calls.

EPOS understands that nothing is more painful than poor connectivity during an online meeting – especially an important one. The connection can affect the future of your career!

With the USB transmitter, the connectivity between PC and ADAPT 660 is brought up to another level.
With the USB transmitter, the connectivity between PC and ADAPT 660 is brought up to another level.

Microphone

I am pretty impressed with the ADAPT 660’s microphone system. EPOS utilized a triple-microphone array in conjunction with noise-canceling technology to minimize background noise while transmitting clear audio. Additionally, the mics are capable of reducing the proximity effect reasonably well.

In directional microphones, the proximity effect refers to the distortion of low-frequency sounds when the microphone is located very close to the sound source. If you move the microphone closer and closer to the sound source, you will notice a rising bass response from the microphone.
One of the microphones on the ADAPT 660 well-embedded in the ear cups.
One of the microphones on the ADAPT 660 well-embedded in the ear cups.

ADAPT 660 Sound

The ADAPT 660 have a highly detailed and well-balanced sound signature that is suitable for most genres of music, as well as content like podcasts and audiobooks. Unlike many consumer-level wireless headphones, this device accurately reproduces low and midrange frequencies.

Aside from the sonic performance following the flat line of neutrality very well, kick drums, vocals, and salient instruments such as guitars are all reproduced accurately without any coloration.

Get the EPOS ADAPT 660 if you wish to hear your music in the way the audio engineers intended.

The ADAPT 660’s bass accuracy is excellent. The majority of the response is neutral, so the mixes have a thump, rumble, and punch. The high-bass range is boosted, resulting in an extra boom in this region.

The midrange response of the ADAPT 660 is remarkably accurate. There is a noticeable flatness in the lower midrange, indicating the lead instruments should have an equal presence within this region. There is a dip in the higher midrange, which somewhat degrades the clarity of lead vocals and instruments. Nevertheless, the vocals remain clear and detailed.

The ADAPT 660 offer decent treble accuracy. Sibilants like cymbals and drums may sound harsh and piercing, and vocals can lack a bit of detail in the treble region.

Despite being publicised as headphones for communication, the ADAPT 660 have high quality sonic performance.
Despite being publicised as headphones for communication, the ADAPT 660 have high quality sonic performance.

Comparisons

Sony WH-1000XM4

Sony’s WH-1000XM4 are widely regarded as one of the best pairs of noise-canceling headphones available. Comparing the WH-1000XM4 to the ADAPT 660, the WH-1000XM4 offers superior active noise cancellation, USB-C connectivity, and quick charging for last-minute power backup.

The WH-1000XM4 also feature deep integration with the Sony Headphones Connect application, which allows for complete customizability, including EQ controls, Sony 360 Reality Audio, touch sensor maps, and location-based noise cancellation settings.

Nevertheless, certain features of the ADAPT 660 make them a better value than the WH-1000XM4. To begin with, the ADAPT 660 support a more comprehensive range of Bluetooth codecs. Furthermore, the ADAPT 660 have a better microphone system than the WH-1000XM4 – which is important now that hybrid working has become the new norm.

ADAPT 660 (on the left) have different strengths as compared to WH-1000XM4 (on the right).
ADAPT 660 (on the left) have different strengths as compared to WH-1000XM4 (on the right).

Sennheiser MOMENTUM 3

Both the Sennheiser MOMENTUM 3 Wireless and the ADAPT 660 have their advantages and disadvantages. The sound profiles of both headphones are very similar, as they share some of Sennheiser’s genes. However, bass lovers will prefer the added thump that the Momentum 3 provide.

In spite of the fact that they both offer excellent noise isolation, the MOMENTUM 3 reduces more noise in the bass range, while the ADAPT 660 isolate better in the mid-range. Compared to the MOMENTUM, the 660 battery performance is superior.

The ADAPT 660 (on the left) have similar detail retrieval capability as compared to the MOMENTUM 3 (on the right).
The ADAPT 660 (on the left) have similar detail retrieval capability as compared to the MOMENTUM 3 (on the right).

Where to Buy

Conclusion

At the end of the day, the EPOS ADAPT 660 sound like they look: sensible, expensive, and mature.

I might be inclined to question whether the anonymity of their looks is sufficient to entice customers in significant numbers. However, the unshakeable virtuosity of their performance will undoubtedly attract more than a few. Those who enjoy a clean and transparent sound signature with a bright profile will find much to like with the 660.

Aside from the excellent noise-canceling ability, the sound quality of this device makes any genre of music sound good - or at least the way it was intended to sound.
Aside from the excellent noise-canceling ability, the sound quality of this device makes any genre of music sound good – or at least the way it was intended to sound.

The ADAPT 660 offer incredible value. Because of COVID-19, many of us are stuck at home, constantly exposed to noise from neighbors and roommates/These headphones provide an easy solution to the struggles of working from home.

However, they have some limitations. Perhaps the most notable is the dated micro-USB port, although it does not affect the overall performance. The outstanding microphone quality and the dedicated Microsoft Teams button outweigh any drawbacks of the port choice.

Additionally, the treble can be a touch bright and I wish that the EQ settings were less limited in the app.

 

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