DPA 4188 CORE Slim Directional Flex Headset Mic combines the legendary sound of the 4088 Directional Capsule with the lightweight and flexible d:fine™ Headset/earset system. The bass response is designed for optimal linearity at 2-3 cm (1 in) from the sound source. This means that the bass roll-off will be relatively prominent at a greater distance – a paramount factor when it comes to rejection of background noise and avoiding feedback. The microphone boom on this model has a 100mm (3.9) boom length, placing the pick-up at the corner of the mouth for most smaller head sizes.