If you're looking at a new pair of headphones (and I'm talking about the on-ear/over-the-ear kind, not the little earbuds), it's definitely worthwhile investing some money into them; especially if you're looking for a good pair to last you for years to come. Over-the-ear headphones are typically more expensive, but they are more comfortable to wear for long periods of time, and tend to product great quality audio. If you're using them out and about, it might be a good idea to look out for a pair with noise cancellation. Finally, while you're at it, why not add wireless Bluetooth capabilities? Does that sound like too much to ask in a pair of headphones? Maybe, the Sennheiser MM 550-X has them all. Better yet, you'll have a chance to win a pair of these headphones at the end of this review!

Sennheiser, a German-based audio company, has produced some great audio equipment, including the Sennheiser HD 598 headphones that I reviewed not too long ago. I wanted to see what other kinds of innovative headphones they had, and the seemingly "all-in-one" package found in the MM 550-X spiked my interest. At $500, they're not very affordable, in fact it's steep! So if you do plan to get one, think of it as an investment that needs to last for at least a decade (or in case Bluetooth becomes obsolete, whichever comes first).

Competitors

The Sennheiser MM 550-X wireless Bluetooth travel headphones have a few competitors that are similar in specifications, such as the Parrot Zik headphones ($350) or the Harman Kardon BT headphones ($250). However, I've personally never heard of Parrot before, and the Harman Kardon BT doesn't include noise-cancellation, which is only found on their model. So, I ultimately went with these Sennheiser MM 550-X because Sennheiser has been, in my opinion, a trusted brand and it included the entire package.

Packaging

The MM 550-X were packed nicely within a plastic mold to keep the headphones from moving around. Underneath is a silver-colored slab-shaped box which includes everything else that comes with the headphones. For the price, included several complimentary items with the headphones. You'll find a sturdy (but not hard-shell) carrying case, a 3.5 mm audio cord so you can still use the headphones via the audio cable instead of Bluetooth, a 6.4 mm jack adapter to be used with audio equipment such as amps, a plane adapter so you can plug your MM 550-X into your plane seat's audio jack, a USB cable for charging, a power supply that works with the USB cable, and various plug adapters so that you can use the power supply in the US, EU, UK, and Australia (and any other countries which use any of those plugs). These additional items really help reinforce the idea that these headphones are meant to be great while traveling.

Specifications

The headphones' specifications are as follows:

• Technology: Bluetooth 2.1 + EDR
• Codec: SBC, apt-X®
• Supported Profiles: A2DP + AVRCP + HSP + HFP
• Headphones Frequency Response: 15 – 22000 Hz
• Sound Pressure Level (SPL): 107 dB (at 1 mW, 1 kHz)
• Total Harmonic Distortion (THD): < 0.1% (typical at 1kHz)
• Ear coupling: Circumaural
• Weight: 179 g
• Music Listening Time: 8 hours with NoiseGard, 10 hours without NoiseGard
• Talk Time: 20 hours
• Charging Time: 3 hours
• Microphone Frequency Response: 100 – 10000 Hz
• Microphone Pickup Pattern: Omni directional

You can tell, especially from the headphones frequency response, that the headphones aren't meant to be audiophile quality, but they offer a significant range considering that they're meant to be travel headphones, ready to go wherever you do.

Design

Each earcup can tilt approximately 30 degrees, and then can rotate about 100 degrees, allowing them to fit on your head very well. Above each earcup is a pivot which allows you to fold the headphones so that they take up less space. It's made out of metal and seems to be very durable. Of course, they are adjustable to fit almost every head shape to its sturdy metal bands. Along the top, you'll find some nice padding, although there's a little less of it right in the middle, so I assume that most of the weight is meant to be distributed on both sides of the head rather than right on top. The better-distributed weight makes the already light MM 550-X seem even lighter on your head. Each earcup is also quite large, so I was able to fit my ear in each completely so that the headphone padding places pressure on my head, around my ears. No ear discomfort whatsoever!

Most of the controls are found on the right side, where you have a master Sennheiser button as well as left, right, up, and down buttons. Left and right buttons usually move between songs, while up and down adjust the volume. The master button in the middle lets you turn the MM 550-X on and off, commence pairing, pause/resume songs, and accept calls. Below this set of buttons, you'll find a button to toggle Bluetooth, turn on the "SRS" 3D surround sound emulator, and the "NoiseGard" noise cancellation feature. The NoiseGard button is also great because you can hold the button for a few seconds to turn on the feature, or you can tap it once to pause and allow sound to pass through the headphones to make conversations easier whenever you want them to.

Each earcup has a microphone which is used for both calls and noise cancellation. The MM 550-X uses a rechargeable battery, and is charge through a microUSB port on the earcup. As such, you can use any microUSB phone charger with the headphones and not have any issues. I've noticed that the microUSB cable that came with the headphones was rather large and made the battery pop out whenever I tried to unplug the cable.

Audio Performance

The Sennheiser MM 550-X feel great on my head, but just how well do they perform? Quite well, I'd say! The mids and highs come across very clear and loud so that you hear practically every detail. The bass was low but didn't distort at all, however it not quite as punchy as I'd prefer. They're slightly punchier than the HD 598 headphones that I reviewed, but those headphones had an open design. Don't get me wrong, they're still present and bass-filled songs will satisfy. However, it just doesn't rumble as much, like when compared to the Audio Technica ATH-M50 headphones I personally own. This can be amended with an equalizer on your computer or smartphone -- amplifiers can't help while you're using Bluetooth.

Other Performance Metrics

The Bluetooth signal between these headphones and my Samsung Galaxy S4 was strong, provided clear audio, and I only heard slight audio glitches whenever the battery level in the headphones was very low. Noise cancellation worked also pretty well (I don't have anything to compare it to, sadly) as it actually made my surroundings seem quieter without adding any strange monotone, and it didn't give me any headaches like some older noise cancelling headphones used to.

Call quality with the MM 550-X was also superb, where I could hear the other person clearly and vice versa. Of course, the quality of voice calls over a cellular network can't be compared to high-quality music, so you can't expect any magic here. At least the microphones work very well even though you aren't directly speaking into them. Lastly, the Bluetooth signal goes quite a distance. I could easily walk to the other side of a large room and still hear my music or phone call perfectly, allowing me to go a lot farther than a cable would. I didn't try to see what the limits were, because I would never put my phone so far away from myself whenever I'm out and about.

The charging and battery times supplied by Sennheiser are surprisingly accurate. Charging takes roughly three hours -- although this still depends on the current produced by the power supply being used -- and listening time with NoiseGard enabled was somewhere between 7-8 hours. Simply put, the MM 550-X can be charged overnight and then reasonably last you throughout the day. I'm sure you won't be spending an entire eight or more hours straight listening to music.

Should You Buy The Sennheiser MM 550-X?

While there's no denying that the MM 550-X are fantastic and that they're excellent at everything they're meant to do, there's still one barrier -- the price. Although I love these headphones to death because of their high quality and ultimate convenience, paying $500 for them is certainly a lot of money. Unless you're absolutely dying to get your hands on these, it may be a better idea to sacrifice a feature or two and get something more affordable. If the emphasis on travel is important to you and could do without the Bluetooth features, get yourself a nice pair of noise-cancelling Bose QuietComfort 15 headphones. Again, these Sennheiser headphones are fantastic, but I'm not sure if they're totally worth the price.

[recommend]MakeUseOf recommends: Buy only if you have the money. They're great headphones but $500 is a lot![/recommend]

The Winner

Congratulations, Jennifer Barnett! You would have received an email from jackson@makeuseof.com. Please respond before October 13 to claim your prize. Enquires beyond this date will not be entertained.

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