If you are looking for a pair of comfortable sports neckband in ear headphones that you can wash and use with helmets and glasses, check out the Sennheiser's PMX 686G!
The PMX 686G Sports by Sennheiser sound great (Omnidirectional pattern), look great and they are ideal for gym workouts, running or when out and about, thanks to the vertical in-ear design which gives you greater situational awareness.
As far as the frequency response, the PMX 686G Sports produce very good bass (20kHz) and rich trebles (18Hz) with perfect sound isolation for awareness of the environment around you. The impedance on these is 30 ohms so smartphones can power the sound loud enough.
The PMX 686G Sports neckband headphones are also sweat and water resistant and have a long 1.2 meter cable with an L-shaped connector jack at the end.
The oval-shaped cable is anti-tangle and reinforced with Para-Aramid fibers similar to Kevlar material.
The PMX 686 SPORTS also feature an in-line remote with built-in mic that is compatible with Android, Windows Mobile and Blackberry devices.
Inside the box, you also get two sets of replaceable Antimicrobial earbuds that you can wash off, 2-year warranty and a nice looking padded pouch to carry the headphones around.