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Going somewhere? Don't forget your Sennheiser MM 400 portable headphones. They're fantastic for enjoying your music and managing your phone calls without getting tangled up in cords. Built-in Bluetooth technology lets you make a hassle-free wireless connection to compatible devices, such as many cell phones, laptop computers, tablets, and MP3 players. You can even use the integrated volume, track skip, and call answer/end buttons on the right earcup for convenient operation while your phone or music player remains safely in your pocket, purse, or backpack.

Great comfort, sound, and convenience
The MM 400's soft padded ear cushions and adjustable headband provide a comfortable fit for hours of relaxed listening, making these 'phones great to have on long trips. The headset's folding design makes for easy storage when you travel. Sennheiser's patented Duofol™ diaphragms deliver detailed, crystal clear sound. And just in case you need it, Sennheiser includes a cable plus an airline adapter for a direct wired connection in situations where Bluetooth isn't permitted, or you want to make use of in-seat entertainment and other wired sound sources.

From the review Sennheiser MM 100 and MM 400 Bluetooth headsets: A family review of a headphone family

"I found the MM 400's light enough to wear for extended periods without any ear fatigue. The open-ear design gave the performance an airy, open feel..."

— Marshall, Crutchfield A/V Writer

Product Highlights:

  • portable, folding, on-the-ear design
  • padded, closed earcups and adjustable headband
  • Bluetooth® wireless operation
  • built-in microphone and wireless earcup controls for hands-free conversations using compatible Bluetooth cell phones
  • rechargeable lithium-polymer battery included
  • single battery charge gives you:
    • up to 20 hours Bluetooth talk time
    • up to 10 hours Bluetooth listening time
  • advanced Duofol™ drivers for outstanding sound quality
  • integrated controls on the right earcup for track, volume, and answer/end call functions
  • frequency response 15-22,000 Hz
  • 56" detachable audio cable with stereo mini plug included for wired listening options
  • airline adapter, USB charging cable, multi-country wall charging adapter, and carrying case included
  • weight: 3.7 oz.
  • warranty: 2 years
  • Our 60-day money-back guarantee

Sennheiser MM 400 Reviews

Average Customer Review:

3 Reviews


Written by: ksp from Wisconsin on March 18, 2015

  • "Coolness Factor"
  • Build Quality
  • Comfort
  • Noise Reduction
  • Sound Quality

Love them just wish I would have went with an over the whole ear headphone set

Pros: -Connected easliy with all of my bluetooth devices -After 1.5 yr battery run time is still at >7 hr -Highs and mid tones are very sharp and clear -Very light, comfortable yet feel secure (have not tried them while running yet) -The auto-mute of music when a call comes in, is automatic and flawless

Cons: -Would like to hear a little more depth and definiton on the lows. -Music in Noise Cancelling mode sucks. -The controls need some attention - I tend to accidentilally put it in noise cancelling mode while adjusting the volume. - Wish they would go louder (but not sure if that is a head phone limitation or whatever the phones are connected to.)

Sennheiser MM 400

Written by: Anonymous from usa on February 12, 2012

the sonud is very good but the ear cover are to small



Handy Headset

Written by: Jonathan S from Greenwich CT on January 29, 2012

Crutchfield Customer Review (What's this?)

The Sennheiser MM400 bluetooth headset is a convenient way to connect to my I-Phone, or I-Pod or I-Pad. It is light weight, compact, and easy to use. The over the ear design lets you hear ambient sounds and conversations, and makes it easy to answer the phone with a tap on its switch on the right ear.

Pros: Compact, light weight, comfortable

Cons: For first time use, it was not totally intuitive how to synch up. Graphic multi lingulal instructions are not my thing.

Hands-on research

What's in the box?

Download owner's manual

  • Bluetooth portable wireless headphones
  • Lithium Polymer battery (installed/ 3.7 volt/ 1 Wh)
  • 56" Wired cable (2.5mm connector on one end and right-angle 3.5mm connector on other)
  • 48" Charging cable (USB type-A connector on one end and micro USB type-B on other)
  • Power supply adatper (5 volt DC/0.5 amp)
  • 4 AC plug inserts (US/ Europe/ UK/ Australia)
  • Airline adapter
  • Soft carrying case
  • Quick Guide
  • Animated manual CD-ROM

Features and Specs

Fit Style On-ear
Earcup Type ---
Noise-canceling No
Bluetooth No
Frequency Response 15-22,000 Hz
Sensitivity 107 dB
Impedance N/A
Weight 3.7 ounces
Cord Length 56"
Airline Adapter Included Yes
iPod Control Yes
Volume Control Yes
Built-in Microphone Yes
Parts Warranty 2 Years
Labor Warranty 2 Years

Product Research


Bluetooth Wireless Reception/Transmission: The Sennheiser MM 400 features Bluetooth v2.1 wireless reception and transmission with a built-in microphone for cable-free use with select Bluetooth enabled phones and audio devices. Supported Bluetooth profiles include A2DP (Advanced Audio Distribution Profile), AVRCP (Audio/Video Remote Control Profile), HSP (HeadSet Profile), and HFP (Hands-Free Profile).

Note: Not all Bluetooth enabled audio devices will be compatible.

Controls: On the right ear-cup there are integrated controls for your connected phone or audio device. Audio controls include volume, skip forward or backward, fast forward or rewind within a song, pause, play, and stop. Phone controls include volume, accept call, reject call, end call, redial, voice dial, and mute.

Note: All control functions must also be supported by the connected device. The 2nd generation iPod touch, iPhone 3G, and iPhone 3GS support only the play, stop, and pause audio functions via AVRCP.

Battery Pack: The MM 400 has a removable Lithium-Polymer battery pack (3.7 volts DC/1.0 Wh) which provides up to ten hours of music playback or up to 20 hours talk time (phone). An AC adapter is included to charge the battery pack; charging time is approximately three hours. The headphones can also be charged using a computer's USB port.

Collapsible Design: These headphones feature a collapsible design with metal-reinforced headband to ensure portability and durability.

Cord & Adapter: The MM 400 will also work as wired headphones, useful when Bluetooth connection is not an option. The headphones come with a 56" mini-jack cable terminated by a 3.5mm connector for a wired connection. An in-flight audio adapter (dual mono 3.5mm) is included for added travel convenience.

Carrying Case: A nylon carrying case is included to protect the headphones during storage or transport.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

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