pressure zone microphone. The DPA BLM6000-B is a unique accessory tool that enhances the versatility of your DPA miniature microphone. It is a soft piece of durable rubber with a diameter of 75 mm. It has an underside cavity for mounting a DPA 4060, 4061, 4062 or 4063 microphone. When placing a microphone on a reflective boundary, you will benefit from the special characteristics of the sound field found here - a 6 dB gain of direct sound and just 3 dB gain of the diffuse sound. This means that the sound captured from this so-called "pressure zone" has higher sensitivity, clarity, and intelligibility compared to the sound captured from the "free air" and serves neatly as a kind of acoustical zoom. The BLM6000 can be mounted on all surfaces that reflect sound such as floors, walls or ceilings. Placing a DPA miniature microphone in this little device on the inside lid of an open grand piano also provides a very destinct sound.