Final Clearance Sennheiser On-Ear Sound Isolating Bluetooth Headphones (MM 400-X) - Black

  • Model #: MM 400-X
  • Web Code: 10209233
(35 ratings)


Roam free with your favourite tunes and these Sennheiser MM 400-X Bluetooth headphones. They're designed to deliver CD-quality sound for the latest apt-X enabled mobile phones and computers.

More Information

  • Featuring the apt-X codec, the MM 400-X can connect wirelessly to any Bluetooth apt-X enabled device
  • Bluetooth 2.1 technology guarantees hands-free convenience without wires and the advanced A2DP profile for Stereo Bluetooth delivers optimized hi-fi stereo sound
  • The invisible microphone ensures that every conversation comes through crystal clear
  • Direct cable option is designed for use on airplanes with the included airline adapter
  • Easy headset controls sit in one intuitive cluster
  • Hi-fi headphone drivers ensure superior dynamic range, detail and excellent bass
  • Padded ear-cushions provide an excellent soft fit, even on long trips
  • The headset folds into a compact bundle for travel and storage, while the headband is metal-reinforced for durability
  • It's easy to replace the battery with a spare on long trips or recharge it via the USB port on your laptop or the supplied lightweight wall charger with different plug fittings for Europe, the USA, the UK and Australia

What's in the Box?

  • USB Wall Charger (US/EU/UK/AU)
  • USB Charging Cable
  • In-Flight Adapters (3.5 mm Double Mono Jack)
  • Audio Cable
  • Carry Case
  • Quick Set-Up Guide
  • User Manual
  • USB Wall Charger For US/EU/UK/AU
  • USB Charging Cable
  • In-Flight Adapters (3.5 mm Double Mono Jack)
  • Audio Cable
  • Carry Case
  • Quick Set-Up Guide
  • User Manual

Manufacturer's Warranty:

  • Parts - 2 Year(s)

Geek Squad Protection

We fix it or replace it.

Choose the coverage that’s right for you when you click Add to Cart.

  • Headphone Style
  • Band Style
  • Sports & Fitness Ear Clip
  • Sound Isolating
  • Noise Cancelling
  • Wireless
  • Bluetooth
    Yes - Bluetooth 2.1 + EDR; Apt-X
  • RF Wireless
  • NFC Ready
  • Effective Wireless Range
    10 m
  • Designed for Sports
  • Designed for Kids
  • DJ Style
  • Professional Grade
  • Water/Sweat Resistant
  • Inline Volume Control
  • iPod/iPhone Control
  • Built-in Mic
  • Folding
  • Cord Length
    1.4 m
  • Plug Material
  • Plug Size
    3.5 mm
  • Plug Shape
  • Ear Cushion Material
  • Power Source
    3.7 V 250 mAh BA 370 PX Rechargeable Lithium-Polymer
  • Frequency Response
    15 Hz - 22000 Hz
  • Impedance
    590 Ohm
  • Magnet Type
  • Sensitivity
    107 Db SPL
  • Colour
  • Weight
    105 g
  • Warranty Parts
    2 Year(s)



Customer Reviews

3.3 / 5
Based on 35 ratings,29 Reviews
Ratings & Reviews

Ratings in Detail

  • 5 Stars
  • 4 Stars
  • 3 Stars
  • 2 Stars
  • 1 Star

Positive vs. Critical Reviews

Positive 77%

24 Reviews

Critical 22%

5 Reviews

Rate & Review this product

Tell others about your experience with this product.

Write a review
  • from Grimsby, ON
  • Jan 28, 2016

Good Bluetooth prerformance

Bought these headphones because I already own Sennheiser headphones and I think they sound very good. They freedom of wireless sounded good to me. Originally I was worried about the drop in sound quality because of bluetooth compressing the file, but they sound great. These are not bass heavy like Beats, but a more balance sound . Great buy on sale.

  • from Saskatoon, SK
  • Jan 25, 2016

okay headphones

The sound quality was not as good as i thought they'd be since these were made by seinheiser but i was proven wrong. The cuffs were too small and these headphones dont really have a good bass. It's more of mids to highs.

  • from Montréal, QC
  • Jan 20, 2016

Good sound!

Nice sound, but very tight uncomfortable fit. Not as comfortable as Bose or Jabra.

  • from Toronto, ON
  • Dec 29, 2015

Battery Life

I have bought two of these Sennheiser bluetooth headphones in the last year. Both of them need new batteries. There aren't any batteries to be found anywhere. Save your money and buy wired headphones because these headphones will not be able to operate without batteries soon after you buy them.

  • from Vancouver, BC
  • Dec 26, 2015

Dont be fooled by its weird look.

pro: sounds very good despite its portable size. comfortable. con: battery retainer doesn't work very well. Battery will come out when pulling on the charging cord. No noise/echo cancelling/reduction. no battery level indicators. This is the entry level model. MM450-x has Noisegard and talkthrough but a bit more expensive.

  • from Richmond
  • Mar 27, 2014

Good stuff

Very happy but ,buy only when on sale this model

  • from Ottawa, ON
  • Mar 19, 2014

Great Headphones at a great deal!

I got these headphones because I needed a comfortable set for using VoIP through my late 2011 MacBook Air. They've been perfect for phone calls and for iTunes, watching YouTube etc. I haven't tried them with any of my mobile devices yet, but I'm sure they would work just as well in that application. The sound is clear, crisp, defined and well-balanced. If you want a subwoofer on your ears, or are looking for studio cans, these aren't the ones for you, but for casual use in an office environment they are great. I can't wait to try them on an airplane.

  • from Toronto, ON
  • Mar 06, 2014

Decent at best

I'd been wanting bluetooth headphones for a while and decided to get the 400X based on the brand and sale price. I'm actually quite disappointed with these, but I'll start with the positive. Pros: -Fold away easily -Convenience of been cable free is great -Ear controls are easy to click plus makes it a more hands free experience Cons: -Shocking low volume with cable -Just decent sound, very little bass -Not very comfortable for long periods or with glasses -Headphone USB flap doesn't always properly close -Microphone audio quality is terrible, callers can't hear Overall, I wouldn't recommend these headphones. The convenience of bluetooth is great but the cons far out weight the pros. Unless they were less than $80, steer clear of these.

  • from Mississauga, ON
  • Mar 04, 2014

took them back

i didnt like these headphones at all . blue tooth was weak . not loud enough for a factory environment. they dont go over the whole ear so dont block out any outside noise. sound quality is good but only if you are home and its very quiet.

  • from Ottawa, ON
  • Mar 03, 2014

Good connection, comfortable, great value @ $[,,,]

Fit - I have a smaller head but found these fit well, a little big at the top but the cushioning is nice. The ear pads are small and don't cover the entire ear. Comfortable under a toque, when working out at the gym, or listening to music at the office. I also sometimes just put them on to block ambient noise - they are not noise-cancelling but muffle sound fine. Performance - connects easily with my Bluetooth computer and phone. The signal only drops occasionally when I'm walking downtown and resumes without having to push any buttons. The on-ear controls are very convenient and have endured this miserable winter well. Call quality is good, the microphone picked up my voice just fine. It sounded a little loud compared to sets where the microphone is directly in front of your mouth but didn't bother me or the other caller. Very convenient to take calls and be able to move around. Sound - agree with the other posters that it is not particularly bass-heavy or loud. Pick up a pair of Beats if this is your preference. I use the EQ on my phone to compensate, which cuts the max volume a little. Overall good quality, not the best Bluetooth OR Sennheiser I've seen... but for $[...] it's what you'd expect. I haven't tried apt-X sound yet as it's not supported by my phone. Battery life - compared to my old Bluetooth headphones (2006 - 2 hours max) it's great. I'd say I get about 4-5 hours of music time, only need to recharge the set every couple of days. Charging is fast through the provided USB cord/plug and there's also a regular headphone cable option if you prefer to have the wire. I don't often use the case as it's a bit bulky but it's nice to have. Summary: good deal, great fit, adequate sound, perfect battery life and accessories.

  • from Toronto, ON
  • Feb 20, 2014

mm 400 ' s

I think that this is the best bang for your dollar. Great sound and clarity. For [price] on sale, saving you $250. Awesome deal. Thanks best buy!

  • from Barrie
  • Feb 07, 2014

Sennheiser Bluetooth

Bought these over the Bose AE2 wireless Bluetooth mainly due to the huge price difference. The sound is adequate crisp and clear in the high and low ranges but the bass leaves a lot to be desired. They do stutter a bit even when sitting next to source. Using the set as a wireless Bluetooth on my smartphone I was told the mic picks up every little noise, especially while driving, compared to riding in a train. They are super easy to set up and the battery life is good (lasted a bit more than a week before second charge, which consequently takes about 3 hours to finish. I would recommend these if you are looking for affordability and ease of use. If you are looking for sound quality...Spend a bit more and go with another brand.

  • from Vancouver
  • Feb 04, 2014

Great product

These are really good headphones. They are small, and they fold up in many ways, which makes them very portable. Also, even with Bluetooth, the sound quality is good. Good highs and mids, the bass is present, however it isn't over empowering. The aluminum headband also makes them very durable. Would highly recommend!

  • from Kingston, ON
  • Feb 03, 2014

Superior Bluetooth Headphones at Sale Price

Good head set I found the range to be sufficient through out the house when linked to the computer but not the same for iPhone. great sound and comfortable fit. I found that they did not bother my ears after a long usage like the over ears type.

  • from Calgary, AB
  • Jan 31, 2014

Good quality and sound

Bluetooth has worked flawlessly for me with an iPhone. Sound quality is good and using as hands free for phone works well. Ear coverage is good.

  • from St. John's, NL
  • Jan 26, 2014

Superior Bluetooth Headphones at Sale Price

The headphones are compact but still cover the ears well - blocking out other sound. A lot of excellent features and flexible use. They are perfect for my requirement. I got them at more than 60% off which was the main reason that they met my requirement.

  • from Toronto, ON
  • Jan 26, 2014


Hooked the headphone up to my desktop via a high end Bluetooth adapter. Pairing was simple with Windows 8.1, and the sound quality is excellent. Did note some stuttering while playing music, particularly when I take a few steps from the desktop - my bluetooth adapter is high end and the latest version (4.0) with a range of 80 feet (instead of the usual 33 feet), and I should therefore not have had the stuttering problem. I paid [price] for the headphone (Boxing Day special), which is apparently listed at [price] - the listed price defies logic, while the [price] appears to be reasonably good value.

  • from Regina, SK
  • Jan 20, 2014

good but not great

These are decent but don't compare to wired phones of similar price. I can't wait until the higher end companies realize that we are demanding top sound quality and comfort in a Bluetooth nfc format. There are many almost as good sets add this for under $100 I own 5 different sets ranging in price from $ 30 to $400 and these fall into the middle of the pack for sound quality and comfort. I also have frequent issues pairing these.

  • from Vancouver, BC
  • Jan 20, 2014

Must-buy headphone when on sale!

This headphone is the only bluetooth headphone with THD lower than 0.1% and sold under [price] when on sale.

  • from Toronto, ON
  • Jan 16, 2014

Pleasantly surprised

I finally got myself a pair of these Bluetooth headphones, and I like them! Setup was relatively easy. Since my desktop PC doesn't have Bluetooth built in, I had to get a Bluetooth USB adapter too. But once that was working with the right drivers, it just worked. I can hear audio from my PC without wires! And it seems I can walk quite far away and still hear. I thought Bluetooth was supposed to be short distance. They are smaller than I though, and it's a tight fit, but sound quality is great, and being wireless is awesome. Great price on sale too.

  • from Toronto, ON
  • Jan 15, 2014

Not bad, but a little disappointing...

I purchased these headphones for $150 on Boxing Day, with a high standard of expectation based on some of the other Sennheiser products I've used. Some issues I've noted: - The battery doesn't last very long - The plug to charge them is very tough. When you pull the cord out, it pulls the whole battery pack out of the headphone - The charge cable is short, so you can't really use them while they're charging - The wireless range isn't very much. A room or two over and a floor down is about as far as you can go. - They're not very comfortable - The built-in microphone picks up a lot of noise around you, and isn't very practical to use when you're on a conference call For [price] they weren't bad, but I can't fathom paying the regular $399 for these.

  • from Saskatoon, SK
  • Jan 04, 2014

Decent set

These headphones have pretty good sound. Music is clear but lacks a little extra oomph in terms of bass (as a gauge, I'm not a max bass fan). Folding design and carrying case a plus. Decent fitting set and comfortable enough. Controls are easy to use both for volume and scrolling. Connect to Windows 8.1 was a breeze as was connecting to my Nexus 4 phone and Asus tft300 tablet. A special note about to windows 8.1. When my laptop upgraded to 8.1, I had trouble connecting to all my bluetooth devices. I no longer have that problem after getting updates through the manufacturer of my laptop. Volume playback was good and loud enough. Good value considering I purchased them during new year overstock sale. I have several headsets includng Sennheiser (wireless home theater), Klipsh buds, Shure wired Studio that all serve specific needs and provide better audio quality. I wouldn't make these your prime, go to headphones, but they do fill in nicely in a pinch for travel, workouts and doing stuff around the house.

  • from Winnipeg, MB
  • Jan 03, 2014

So So at Best!

These headphone i was told could hook up to playstation cannot connect. On mac laptop connection was poor. iPhone connection was decent. overall I'm not very impressed.

  • from Regina SK
  • Jan 02, 2014

Not very good

The sound quality is pretty good when connected to some device that supports aptx. However that's all that I can say is good about the product. The construction seems rather flimsy and cheap for a higher end product. The included usb cable was cheap quality and fit tightly, far tighter than it should. The rubber usb plug cover took me over 10 minutes to put back in place because of poor fit. What's even worse, the headphones barely fit my head with the full extension of the unit. It also fits too tight and is not comfortable at all for on ear headphones. Finally, the volume barely reaches an acceptable level at full, these are not very loud at all.

  • from Edm Ab
  • Jan 02, 2014

Excellent bluetooth headphones

They sound great. Can't complain for how much I got them for [price] on Boxing Day! I use these for the gym and happy. I'm now wireless and no cords to get in the way!

  • from Cambridge, ON
  • Jan 02, 2014

Happy with purchase

These headphones produce clean and crisp sound. They are a little light on bass if compared with Beats headphones but some people consider those a little bass heavy to begin with. Connecting and streaming with bluetooth devices works perfectly, I use these with my usb pc dongle and my smartphone. You can definately tell the difference if you pair it with an Apt-X enabled device such as the GalaxyS3/S4. The built in microphone works well. I have had no complaints from anyone on the other line. Overall, a nice and portable package that I would highly recommend.

  • from Toronto, ON
  • Jan 02, 2014

Just amazing

I find them to be great.only thing i dont like they dont connect to my windows 8.1 tablet.but to my phone great sounds great.@ [price].you are not going to find better bluetooth headphones.just what i think.and great return policy @bestbuy.good shopping.

  • from Toronto, ON
  • Jan 01, 2014

Decent enough

These headphones are decent enough for home use and phone calls. They aren't really loud at the highest volume setting. This means when I'm sitting on a bus and the engine is roaring I can barely hear the music. They also look kind of cheap and flimsy considering the price. At least no one would want to steal them.

  • from Nunya bizness
  • Dec 28, 2013

Good overall

These headphones are a good buy they sound really good are light seem sturdy. Only negative thing I can say about them is the bass is not very strong which was a little disappointing but overall otherwise I would recommend them they are a good buy on sale but they are definitely not worth the full price.

Buying Guide

Sports Headphones Buying Guide Best Buy offers a wide selection of sports headphones with free shipping on orders over $25. Learn which kind best fits your on-the-go lifestyle. Read More >