SONNET 2 Audio Processor


Made for the most natural hearing in any listening environment

SONNET 2 is our latest BTE audio processor for MED-EL cochlear implants. From Adaptive Intelligence to wireless connectivity, SONNET 2 is packed with tons of new technology that’s made for the best hearing experience possible.

  • Outstanding hearing performance
  • Sleek design
  • Wireless connectivity
SONNET 2 Made for Everywhere

Made for Everywhere

SONNET 2 is made for exceptional hearing performance, even in challenging listening environments. Automatic Sound Management 3.0 seamlessly adapts for optimal hearing and hands-free control. From busy offices to noisy restaurants, ASM 3.0 enables a clearer, more comfortable hearing experience.

Microphone Directionality
Reduces noise from behind and focuses on sounds to the front for significantly better hearing in noise.

Automatic Volume Control
Dual-Loop Automatic Gain Control instantly adapts volume levels to make loud sounds more comfortable and soft sounds easier to hear. 

Ambient Noise Reduction
Reduces continuous ambient noise—such as a desk fan—for easier, clearer listening.

Adaptive Intelligence
Intelligently adapts front-end processing to changing listening environments for the best hearing in any environment.

Wind Noise Reduction
Minimizes continuous wind noise for improved listening in outdoor environments.

Transient Noise Reduction
Instantly attenuates sudden loud noises for comfortable listening in any setting.

Natural Loudness Growth 

Our Dual-Loop Automatic Gain Control instantly adapts volume levels to make loud sounds more comfortable and soft sounds easier to hear. With an extended loudness growth range and compression ratio (3:1), our loudness growth more closely follows natural loudness growth in the cochlea. 

This is an advantage for loudness balancing with bilateral CIs, or if the other ear has natural hearing, such as single-sided deafness or for bimodal listening with a contralateral hearing aid.

Microphone Directionality

SONNET 2 uses Microphone Directionality to mimic the natural pinna effect by reducing sounds behind and focusing to the front of the listener. This enables significantly better hearing performance in noisy environments.

Natural directionality provides significant advantage in everyday life, and Adaptive directionality provides a powerful boost in complex noise

Structure Preservation

Our incredibly flexible lateral wall arrays can gently adapt to the shape of each individual cochlea to protect the delicate natural structures. Multiple recent studies have shown only MED-EL arrays enable 100% scala tympani insertions. 

Scala tympani placement enables significantly better hearing outcomes. Our gentle arrays also enable hearing preservation, for combined electric acoustic stimulation with SONNET 2 EAS. 

Literature Search Report (2020), Data on File, MED-EL n=1,399
O´Connell et al. 2016

Complete Cochlear Coverage

In natural hearing, the nerve fibers of the spiral ganglion are tonotopically organized and extend the full length of the cochlea. If an electrode doesn’t cover two full turns (720°) of the cochlea, it can’t stimulate these nerve fibers to provide accurate pitch-place match.  

Our long, flexible arrays can be safely inserted all the way to the apical region to provide natural tonotopic stimulation across two full turns of the cochlea. With complete cochlear coverage, recipients can enjoy a natural pitch match from the very beginning. This enables significantly better hearing performance and a more natural hearing experience for your patients. 

Data on file, calculated from mean cochlear parameters
CI Electrodes

FineHearing Sound Coding

In nature, the cochlea uses two types of sound coding. Place-pitch tonotopic coding is used along the whole frequency range. In addition to place-pitch coding, low-frequency sounds are also coded by rate. With this time-coding, the frequency of nerve signals is synchronized to the frequency of the sound below ~1000 Hz.

That’s why we created the only cochlear implant sound coding that mimics the natural time-coding for low frequencies and provides place-pitch match throughout the cochlea. By mimicking natural sound coding, FineHearing provides much more natural sound quality.

Benefits: Music

Music is a complex form of sound, making it one of the most challenging things to listen to. So when recipients can enjoy listening to music, you know they’ve reached a whole new level of hearing. 

Listen to
music weekly
or daily
Music sounds
Müller et al. 2012

Benefits: Sound Localization

Whether it’s a noisy classroom or a busy sidewalk, knowing where a sound is coming from is essential for your patients. By providing more accurate interaural time differences (ITDs) and interaural level differences (ILDs), our cochlear implants enable more accurate sound localization than any other cochlear implant. 

SONNET 2 Processor Design

Processor Design 

SONNET 2 is a sleek, lightweight BTE processor with a modular design, allowing you to adapt it to best fit the needs of each individual. With built-in water resistance, flexible wearing options, rechargeable batteries, thousands of color configurations, and a durable design, it’s made for all-day comfort and performance in everyday life

Design Award 2019

Awarded to the SYNCHRONY System, comprising the SONNET 2 Audio Processor and accessories, SYNCHRONY 2 Cochlear Implant, and MAESTRO 8.0 fitting software.

SONNET 2 Colours

Mix & Match

With thousands of color combinations and stylish design covers, SONNET 2 lets your patients blend in or stand out.

SONNET 2 Child Saftey

Child Safety

With tamperproof design, DL-Coil link-check indicator, locking coil cable, and titanium battery pack locks, SONNET 2 offers the highest level of child safety available for CIs. 

SONNET 2 Rechargable Batteries

Rechargeable Batteries 

Easy-to-use rechargeable batteries offer the lightest and most compact wearing option for SONNET 2. Or go for up to 4 days on disposable zinc-air batteries. 

SONNET 2 WaterWear

Ready for Water

Splashproof design provides protection against rain or sweat all day long. And with the WaterWear cover, SONNET 2 is ready for swimming.

SONNET 2 Flexible Wearing Options

Flexible Wearing Options

ActiveWear is the lightest behind-the-ear wearing option available. And with BabyWear, you can clip the entire processor to clothing, making it ideal for infants.

SONNET 2 Optimized Handling

Optimized Handling

Upgraded design makes it easier to change microphone covers, use rechargeable batteries, and secure the battery pack cover. 

SONNET 2 Made for Connectivity
SONNET 2 - Made for Connectivity

Made for Connectivity

SONNET 2 makes it easy to stream phone calls or connect to music, movies, and television. With integrated 2.4 GHz wireless connectivity, SONNET 2 lets your patients connect to almost any audio source. Our all-in-one AudioLink accessory makes it easy to stay connected, and the direct streaming of music and phone calls from any compatible smartphone or tablet is simple with AudioStream.*



With AudioLink, you can stream phone calls right to SONNET 2. You can also connect to music or stream high-quality sound from TVs or tablets. AudioLink also has a built-in microphone, so you can use it as a remote microphone. This offers an easy-to-use listening boost in busy meetings and restaurants or for clearer listening in a classroom. 

  • Bluetooth® streaming
  • Remote microphone
  • Direct audio input



SONNET 2 users from as far back as 2014—farther back than any other cochlear implant manufacturer in the world—can enjoy direct wireless streaming. After sliding the AudioStream cover onto their audio processor, they can stream phone calls and music from any compatible smartphone or tablet.*

  • Streaming via Bluetooth® Low Energy
  • High-quality sound
  • True stereo support for bilateral recipients
  • Bimodal streaming from compatible smartphones**

AudioKey 2

AudioKey 2

Control and personalize SONNET 2’s user settings, check on a user’s hearing, view detailed data on wearing time, program, and connectivity usage as well as locate SONNET 2 when you want to find it—all with the AudioKey 2 app. The guardian roles let you create multiple users’ profiles for flexibility and security as you manage multiple users and processors.

  • Remote control
  • Extended data logging for SONNET 2
  • Required for initial setup of AudioStream

Download Download

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FineTuner Echo

FineTuner Echo

The FineTuner Echo remote is a compact, easy-to-use remote with a built-in display. This bi-directional remote shows current settings, including program, volume, connectivity. E-paper display makes it easy to read, even in bright sunlight.

  • Bilateral support
  • Integrated speech processor test device
  • E-paper display

You can check which version of SONNET 2 your patient has here. For full details on its features, please see the technical data.


Why MED-EL: 
A Trusted Partner

For more than 30 years, MED-EL has been a trusted partner and innovation leader in hearing implants. We’re here to work together with you, and we’re committed to providing outstanding service and support for our professional partners.

With the most advanced cochlear implant systems, we offer the best hearing experience for your patients and the best clinical experience for you. 

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Technical Data


Width: 37.4mm
Height: 67.6mm with Battery Pack Cover Max
Height: 56.7mm with Battery Pack Cover Standard
Height: 51.4mm with Battery Pack Cover Micro
SONNET Audio Processor Size
Thickness: 5.9mm
Thickness: 9.3mm

You can check which version of SONNET 2 your patient has here.

SONNET 2 Me1512 Audio Processor

Weight and Dimensions

  • 6.1 g (with ActiveWear)
  • 10.6 g (Me1512 with two 675 zinc-air batteries)
  • DL-Coil: 4.6 g, 32.8 mm x 5.8 mm
  • DL-Coil: 5 magnets available in 9 strengths
  • Durable coil cables available in 3 lengths:
    • 6.5 cm (2.6 in)
    • 9 cm (3.5 in)
    • 28 cm (11.0 in)


  • Processor & Coil: Mixture of polycarbonate and
    acrylonitrile-butadiene-styrol polymer
  • Earhook: Polyamide (PA)
  • Cable: PVC and TPE Evoprene
  • Biocompatible according to ISO 10993-1
  • Latex-free*


  • Compatible with all MED-EL multichannel cochlear implants
  • MAX Programming Interface
  • MAESTRO System Software 6.0 or later
  • Compatible with hearing aids of all brands and types

Product Features

  • Frequency Range 70–8500 Hz
  • Splash-proof design with IP54 rating
  • Dual microphones
  • Datalogging
  • Tamperproof design
    • Secured earhook
    • Locking battery pack
    • Choking hazard avoidance
    • Additional fixation options
    • Locking coil cable (locked to coil and control unit)
  • Link monitoring function with LED indicator
  • Four program positions
  • Continuous volume and sensitivity control with FineTuner or AudioKey 2 app

Sound Processing Features

Front-End Processing

  • Automatic Sound Management 2.0 (ASM 2.0)
  • Microphone directionality
  • Wind Noise Reduction
  • Automatic Volume Control with Dual-Loop AGC
  • Input Dynamic Range (IDR) of 78 dB

Sound Coding Strategies

  • FS4 (Fine Structure Processing up to 1 kHz on 4 apical channels)
  • FS4-p (Fine Structure Processing up to 1 kHz on 4 apical channels with Intelligent parallel Stimulation for even higher temporal accuracy)
  • FSP (Fine Structure Processing typically up to 350 Hz on 2 apical channels)
  • HD-CIS (High Definition CIS)
  • Biphasic or Triphasic stimulation pulses
  • Supports 250 spectral bands



  • 2.4 GHz wireless communication
  • Direct wireless audio streaming via Bluetooth Low Energy with AudioStream
  • True stereo sound quality
  • Support for bilateral usage
  • Integrated telecoil



  • Dimensions: 68 x 38 x 17.5 mm
  • Weight: 35 g
  • Remote microphone
  • Hands-free phone calls
  • TV streaming
  • Music streaming
  • Direct audio input (DAI)

AudioKey 2 App

  • Remote control functionality
  • Guardian roles
  • Find My Processor
  • Send feedback
  • Compatible via AudioLink

FineTuner Echo

  • Dimensions: 104 x 38 x 11 mm
  • Weight: 32 g (including battery)
  • Compact remote control with bi-directional communication
  • ePaper Display
  • Test audio processor microphones
  • SONNET battery status

WaterWear Cover

  • Waterproof up to 4 m depth
  • Can be used in salt, fresh and chlorinated water

Battery Options

Zinc-Air Batteries

  • Up to 60 hours of use with a set of 2 disposable zinc-air 675 batteries

Rechargeable Battery Max

  • Dimensions: 32 x 14 x 7 mm
  • Processor weight with battery: 10.4 g
  • Usage time: Up to 17 hours
  • Charging duration: ~6 hours
  • Charging/discharging: >1800 cycles (80% capacity)**

Rechargeable Battery Standard

  • Dimensions: 22 x 14 x 7 mm
  • Processor weight with battery: 9.1 g
  • Usage time: Up to 10 hours
  • Charging duration: ~4 hours
  • Charging/discharging: >1100 cycles (80% capacity)**

Rechargeable Battery Micro

  • Dimensions: 16 x 14 x 7 mm
  • Processor weight with battery: 8.1 g
  • Usage time: Up to 7 hours
  • Charging duration: ~3 hours
  • Charging/discharging: >1100 cycles (80% capacity)**

Charging Unit

  • 4 simultaneous charging slots
  • Power & charging indicator lights
  • USB powered: 5V DC, 500mA
  • USB power adapter: 100–240V AC (~50/60 Hz)

The Bluetooth® word mark and logos are registered trademarks owned by the Bluetooth SIG, Inc. and any use of such marks by MED-EL is under license.

Please find detailed information and specific conditions for use for each product in the respective instructions for use.
All functions and features may not be available in all markets. Enabling features on the hardware may be subject to technical considerations.

* Whereby “free” means “not made with latex” according to current FDA guidance: “Recommendations for Labeling Medical Products to Inform Users that the Product or Product Container is not Made with Natural Rubber Latex”, 2014.
** Charging Cycles dependent on individual usage.

Direct Wireless Streaming Cover for SONNET Series Audio Processors

AudioStream can be used as a Made for iPhone (MFi) Hearing Device and supports the Audio Streaming for Hearing Aids (ASHA) technology. MED-EL recommends keeping your device(s) updated with the latest version of the iOS or Android operating system. AudioStream is compatible with iOS version 11 or later and Android version 10 or later.

* AudioStream for SONNET series audio processors is compatible with Apple and Android devices. For a detailed list of compatible devices, see below.
** Bimodal streaming is only possible with Android 12 or later and hearing aids compatible with Audio Streaming for Hearing Aids (ASHA) technology. For a detailed list of compatible devices, see below

Devices Compatible With AudioStream

Apple Devices

Check to see if your Apple device is compatible with AudioStream.

Android Devices

Check to see if your Google Pixel device is compatible with AudioStream.

Samsung Galaxy S23, Samsung Galaxy S22, Samsung Galaxy S21+,  Samsung Galaxy S21, Samsung Galaxy S20 Ultra, Samsung Galaxy S10+, Samsung Galaxy S10, Samsung Galaxy S10e, Samsung Galaxy S9+, Samsung Galaxy S9, Samsung Galaxy Z Fold2 5G, Samsung Galaxy A71, Samsung Galaxy A70, Samsung Galaxy A52, Samsung Galaxy A51

OnePlus 9 Pro, OnePlus 9

Xiaomi 11T Pro

Oppo Find X5, Oppo Find X3 Pro (CPH2173)

Smart TVs and Digital Media Players

Amazon Fire TV Cube (3rd Gen), Amazon Fire TV Cube (2nd Gen)

Certain third-party applications (for example, the Roku App for Roku and Roku TV) can be used with compatible devices to stream audio directly to AudioStream.

Devices Suitable for Bimodal Streaming

For bimodal streaming, you simply need an Android smartphone with the Android 12 operating system or later, a hearing aid with ASHA (Audio Streaming for Hearing Aid) technology, and an AudioStream. The below lists include devices specifically tested and confirmed by MED-EL to be suitable for bimodal streaming. Other Android devices and hearing aids with the necessary technologies may also be suitable for bimodal streaming when using AudioStream.

Android Devices

Check to see if your Google Pixel device is suitable for Bimodal Streaming.

Samsung Galaxy S23, Samsung Galaxy S22, Samsung Galaxy S21+,  Samsung Galaxy S21, Samsung Galaxy S20 Ultra, Samsung Galaxy Z Fold2, Samsung Galaxy S10e

Xiaomi Mi 11T Pro

OnePlus 9 Pro

Oppo Find X5, Oppo Find X3 Pro

Hearing Aids

Beltone Imagine, Beltone Amaze, Beltone Boost Ultra, Beltone Rely

Oticon More, Oticon Real, Oticon Intent

ReSound ENZO Q, ReSound LiNX Quattro, ReSound Key, ReSound One 

Signia Pure Charge&Go X, Signia Pure Charge&Go AX, Signia Pure Charge&Go IX, Signia Pure Charge&Go T IX

Starkey Livio AI, Starkey Evolve AI

Widex Moment

Although MED-EL aims to provide as many users as possible with seamless device compatibility, MED-EL cannot guarantee full compatibility or troubleshooting support with all devices and the information provided above should only be used for reference.

  1. Vaerenberg, B., Govaerts, P.J., Stainsby, T., Nopp, P., Gualt, A., & Gnansia, D. (2014). A uniform graphical representation of intensity coding in current-generation cochlear implant systems. Ear Hear. 35(5): 533–543
  2. Dorman, M.F. & Natale S.C. (2018). Auto-Adaptive: A noise level-sensitive beamformer for MED-EL cochlear implant patients. J Am Acad Audiol.
  3. O’Connell, B.P., Cakir, A., Hunter, J.B., Francis, D.O., Noble, J.H., Labadie, R.F., Zuniga, G., Dawant, B.M., Rivas, A., & Wanna, G.B. (2016). Electrode location and angular insertion depth are predictors of audiologic outcomes in cochlear implantation. Otol Neurotol. 37(8):1016–1023.
  4. O’Connell, B.P., Hunter, J.B., Haynes, D.S., Holder, J.T., Dedmon, M.M., Noble, J.H., Dawant, B.M., Wanna, G.B. (2017). Insertion depth impacts speech perception and hearing preservation for lateral wall electrodes. Laryngoscope. 127(10):2352-2357
  5. Rader, T., Döge, J., Adel, Y., Weissgerber, T., & Baumann, U. (2016). Place dependent stimulation rates improve pitch perception in cochlear implantees with single-sided deafness. Hear Res., 339, 94–103.
  6. Müller, J., Brill, S., Hagen, R., Moeltner, A., Brockmeier, S.J., Stark, T., Helbig, S., Maurer, J., Zahnert, T., Zierhofer, C., Nopp, P., & Anderson, I. (2012). Clinical trial results with the MED-EL fine structure processing coding strategy in experienced cochlear implant users.
  7. Killan, C., Scally, A., Killan, E., Totten, C., & Raine, C. (2019). Factors affecting sound-source localization in children with simultaneous or sequential bilateral cochlear implants.