Enter a search term above and hit enter
Please wait...
High resolution in-ear headphones

| Write a review
HEM4High resolution in-ear headphones

High resolution in-ear headphones

The High Resolution certified HEM series set a new standard for accuracy, speed and comfort. Designed for music lovers and professionals, these innovative in-ear headphones offer budding artists, home recording musicians and DJs incredible audio reproduction. Combining the latest balanced armature driver technology with advanced crossover design, the HEM series reveal a wider frequency range for the ultimate listening experience.


Hi-Res certified

High Resolution certified – for studio-quality audio

Twice the frequency

Twice the frequency range of other balanced armature IEM’s - up to 40,000 Hz

Advanced Crossover

Linear-phase crossover for seamless driver integration

The most advanced drivers

Latest generation Knowles™ balanced armature drivers for incredible accuracy

Hi-Res performance

The HEM series of in-ear headphones let you hear every track in exceptional clarity – for rich full-bodied sound. The combination of cutting-edge design and Hi-Res certified balanced armature driver technology results in balanced sound with crystal clear highs and explosive bass.


Crossover design

The HEM series incorporate a three-way phase-coherent crossover design that achieves linear phase performance. The result is a natural, three-dimensional soundstage, lightning-fast transients and crystalline transparency.


Knowles™ balanced armature drivers

Featuring the latest generation of balanced armature drivers, the HEM series can reach frequencies as high as 40,000Hz - twice the frequency range of other balanced armature IEMs’. Each HEM model houses either four (HEM8), three (HEM6), two (HEM4) or one (HEM2) Knowles™ balanced armature drivers in each earbud – designed to produce pure, authentic sound from a compact body.


Pure sound, wherever you go

Two tangle-free cables are included so you can choose between a microphone and inline remote for convenience, and a high-end cable for the best possible performance. The high-end cable is made of OFC and silver, while the 2-pin cable connectors are a proprietary mix of silver and copper with separate ground return for each channel.



Constructed with acoustically calculated, vibration-free Lexan™ earpieces the HEM series allow for prolonged listening without fatigue at any volume level. The in-ear monitors are lightweight making them ideal for use at home, in a recording studio, on stage or on the go.


Superior comfort

For maximum comfort and performance the HEM4 comes with two types of ear tips in a range of sizes for a snug, slip-free fit. These include Comply™ soft memory foam ear tips which shape themselves to fit perfectly in the ear canal, offering superior isolation from noise and creating incredible bass response.

Model HEM8 HEM6 HEM4 HEM2 HEM Dynamic
Colour available Black Black Blue Red Crystal white / Charcoal black
Number of drivers (per earbud) 4 3 2 1 1
Frequency range 10 - 40,000Hz 18 - 40,000Hz 18 - 40,000Hz 20 - 40,000Hz 20 - 40,000Hz
Applications Professional monitoring tool with the most accurate bass. Perfectly balanced for professional use on stage as well as music on the go. Reflects sound better than most in its class. Designed for professionals and audio enthusiasts. A single full range driver. Ideal for home musicians and audio enthusiasts. A single dynamic 6mm driver. Ideal for music on the go.

What is a Balance Armature driver and how does it work?

The HEM range of in-ear headphones are able to reproduce musical performance in the way that a professional full range speaker does. The new range is comprised of a modular design that includes a set of drivers controlled by a patented cross over design. An exclusive NuForce designed linear phase network is able to maintain the right note, at the right time and in the correct frequency to be played at all times. This set up allocates specific frequencies to a designated driver ensuring a perfect integration of frequency and phase which result in clarity speed and details that are constant at any volume.

The HEM’s reference performance calls for the best connection and delivery from a source. A hybrid silver/copper-conductor has been tailored specifically for the HEM and is used in the additional high-end braded cable that is offered with every HEM set. In fact, almost as much care and attention has been lavished on the design of the cable as on the earphones themselves, further enhancing and tuning the tonal balance to perfection.

Balanced armature drivers

The latest Knowles balanced armature driver is superior to a single dynamic driver. It is able to reach frequencies of up to 40,000Hz without flex and distortion. Unlike a conventional dynamic driver, the balanced armature drivers use a magnet to move a small diaphragm, resulting in vanishingly low distortion levels. The combined ability of the drivers to deliver a greater range of frequencies, in comparison to a dynamic driver, makes them an ideal professional tool for those who record at higher than CD frequencies.

The HEM series is ready for use by those who are mastering or listening to DSD audio files. Due to the miniature size of the armature driver, a number of drivers can be combined together to create a full range sound field. The result is an astonishing life-like, accurate sound that is able to maintain clarity even at the highest volume levels and retrieve critical details at very low volume levels.

Linear-phase crossover

To harness the best results from the use of up to eight in-ear speakers in the HEM range, a patent pending crossover mechanism has been adopted. An innovative phase linear mechanism in the form of a first order Butterworth crossover design was chosen to distribute frequencies and maintain the sound in the correct phase at all time. Not only is this unique set-up able to accurately and perfectly assign the frequency to the appropriate driver (bass frequency to the bass driver etc.) it also ensures that the diaphragm movement of each driver is coordinated between all eight inner drivers.

Careful attention to materials and technology used in this new HEM range has resulted in the most accurate delivery of sound to the listener’s ear. The combined result creates a sound stage that is wider and deeper, eliminating the illusion of sound centred between the ears and placing the music across and even in front of the listener.

Hi Res certificate

The NuForce HEM range has been able to meet the exact standards which are awarded to a very select group of models. The Hi-Res certification program is a recent effort that combines both the Consumer Electronics Association (CEA)® and the Japan Audio Society (JAS). The partnership was established in 2014 to help promote and support the marketplace growth of High-Resolution Audio (Hi-Res Audio or HRA) devices and content. With the growth in popularity of high resolution audio, the NuForce range is able to meet and exceed the very demanding technical factors that are involved in the replay of DSD content. Combined with the Hi-Res certified uDAC5 the HEM series of in-ear headphones offer a complete high resolution audio solution for audio enthusiasts, budding home musicians, DJs and gamers.

Recommended products



Expert reviews

HiFi Choice
HiFi Choice
December 2017

It is a well-made earphone and the blue finish on the housings is smart without being too obtrusive.

Its presentation is very slightly forward, which gives it a consistently lively and exciting edge.

The use of an armature for the bass instead of a dynamic driver seems to lend it speed and definition that is very useful whenever there is a more complex arrangement to deal with and, as before, it does well to draw you into the performance.

In the noisiest surroundings, it is able to keep any interference at bay without the need to raise the volume.  Combines with the useful level of sensitivity on offer and the inline remote, the HEM4 performs well with lower-powered sources, ensuring it is a tempting prospect for commuters

September 2017

“It doesn’t matter which music content you play, the HEM4 plays unbelievably"

August 2017

“The Optoma NuForce HEM4 in-ear headphones are a class above. Thanks to the linear frequency response, these in-ears are particularly suitable for the demanding music listener, who prefers a well separated and detailed sound quality.”

May 2017

"In terms of sound, the HEM4 impress first of all with its great dynamic sound. All musical content simply sounds incredible right from the start."

Price/ performance: good – very good.

April 2017

The HEM4 gives a clear and detailed presentation. I got a great sense of texture and tonality with an impressive soundstage.

These IEMs produced the kind of accuracy I would expect from more expensive earphones. Classical and acoustic music was handled with warmth and definition, whilst the heavier end of my catalogue had bite and power.

Some may find these lacking in the lows but everything was nicely balanced to these ears.


March 2017

“So much quality is rare in the in-ear segment. With the Nuforce HEM4 everything seems to be right. Material selection, sound reproduction, equipment and a really good and passive noise cancelling.”

HiFi Pig
HiFi Pig
January 2017

“I have reviewed a number of Optoma IEMs in the past and this product was for me the pinnacle of my acoustic travels with the company.”

“Playing Britten’s Sinfonia da Requiem (24/96kHz, Kansas Symphony Orchestra, Michael Stern) on that bicycle helmet looking IEM gave a transparency of sound that more than met its price point.”

“At a penny under £250, these IEMs are a highly recommended choice for the serious music listener and professional alike. With musicality pouring out of everything I played with both warmth and clarity, it played classical music with affection and heavy rock with grunt. Once you get used to inserting in your ears you will wonder why you didn’t wear earphones this way before.”

January 2017

"Advanced in-ear headphones with neutral sound. They offer analytical and detailed sound and are feather-light and sit rock-solid, even when jogging. In addition, the package is convincing - all in all a good candidate with a good price."

December 2016

Tested Technology explains Hi-Res audio with some help from the Optoma NuForce HEM4 in-ear headphones:

“The technology is genuinely serious too—this is definitely not a Beats-type stitch-up.”

“…the HEM series uses a curiously snail-shaped enclosure made of Lexan, a proprietary lightweight thermoplastic polymer resin used in jet fighter canopies for its strength, impact resistance and—particularly significant in audio applications—mechanical stiffness.”

“The stiffness of Lexan resists the tendency of the HEM4 enclosure to resonate in sympathy with the sound waves being delivered, so you get nothing more nor less than what the input signal is meant to deliver.”

August 2016

“NuForce delivers with its HEM4 a convincing overall package which could be located somewhere between consumer-and professional equipment.”

"The HEM4 is packed with a wealth of accessories that includes 2 cases and 2 cables. In addition to the accessories, you get of course the In-ear itself which convinces qualitatively."

July 2016

“High-res music files will be played by the blue Optoma in-ears with an astonishing precision. Mozart Violin concert with 24 bit and 192 kHz, normally something for bigger over ear headphones, sounds incredible with spatial and amazing clarity.”

“The instruments sound razor-sharp, even hectic sequences remain supreme.”

“High-res sound in miniature – the NuForce HEM4 from Optoma make it possible. The in-ear lightweights are even an option for classical music lovers and it comes with a huge range of accessories.”

June 2016

“NuForce has done a great job with their new HEM line-up. The lightweight, ergonomic shells ensure comfortable listening sessions."

“Stepping up from the HEM2, we come to the HEM4 double-BA IEM. These stick out as the more "reference" sound signature in the lineup.”

Frequency response
18Hz - 40,000kHz
Driver type
High resolution Knowels™ balanced armature
Crossover type
Linear Phase


Frequency response
18Hz - 40,000kHz
Cable length
38 Ohms
Maximum input power
Maximum input sound level
Connections input
3.5mm jack
Connections output
2 pin connector for each ear piece
Driver type
High resolution Knowels™ balanced armature
Number of driver(s)
Crossover type
Linear Phase
Inline remote
Track+,track-, play, pause, answer phone, disconnect phone

Weight and dimensions

Weight (kg)
0.005 (5g)

In the box

Standard accessories
2x 1.38m detachable cables
3.5mm - 6.3mm gold-plated adapter
6x pairs soft silicone ear tips (S/M/L)
2x pairs Comply™ memory foam ear tips (M/L)
Brush / cleaning tool
Lapel clip
Waterproof display case
Carrying case




Verified owner

Recently viewed

This website uses cookies to give you the best online experience. If you'd like to know more or change your preferences, our Cookie Policy explains more.You consent to our cookies if you continue to use our website.