The Sennheiser e901 boundary mic is a seriously versatile microphone that's best known for use inside bass drums, but is equally at home on a conference table, mounted to the lid of a piano, or capturing the ambience of a large room. This boundary condenser microphone has a "half cardioid" pattern and is designed to sit directly on a surface -- slip-free rubber padding helps to keep it from moving around -- delivering a remarkably phase-coherent sound without capturing unwanted reflections from the surface to which it is mounted. A built-in XLR connector means there's no need for a special cable, just plug in a regular mic cable and sit the e901 on a pillow inside your kick drum for a thunderous sound that hears the whole inside of the drum, not just the beater head.