Bringing back memories of Sony's 'Street Style' headphones, the Sennheiser MM 100 headset is an on-the-ear, wrap-around model.
This style is well suited to active users - it secures well against the ears without excessive clamping, with the added bonus of open ear-cups to let in ambient sound (which is important if you're running through traffic-heavy streets, for example). It also helps that the Sennheiser MM 100 headset weighs just 54g; you can feel it sitting on your head but there are no comfort issues if you're wearing it for a long period.
Unlike the button-heavy sides of the Sennheiser MM 450 Travel headset, the Sennheiser MM 100 headset has all its buttons on the right - a general purpose play/power button, skip and review buttons as well as a volume control. The play button also answers and ends phone calls, so you can store your Bluetooth-enabled mobile safely in your bag or pocket. We still can't get used to talking to a pair of headphones, but it's nonetheless a nifty feature.
Sound quality from the Sennheiser MM 100 headset remains consistent even when cranked up to high volumes. There's a reasonable amount of upper bass that fits in well with the warm mid-range and relatively detailed treble, making for an aural signature that's heavy and musical.
We would have liked a little more clarity in the higher registers - at times music can sound slightly muffled. Our main annoyance is the fact that the Sennheiser MM 100's ear-cups leak noise badly at anything higher than moderate volume levels; these are not the headphones for a workplace or a crowded bus, unless you want everyone else to hear your music.
Being a lightweight Bluetooth headset, we didn't expect spectacular battery life given - but 7.5 hours is impressive. Less thrilling is the long wait between listening sessions; the Sennheiser MM 100's battery takes 2.5 hours to reach a full charge.
Coming with the slightly-higher-than-reasonable Sennheiser price tag, the Sennheiser MM 100 is nonetheless a competent headset for active users.
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