Was sent the latest update from Wildlife Acoustics on how their new SM2BAT+ remote bat echolocation recording device fits into the survey requirements for the endangered Indiana bat. This is not something that would really affect us in the UK, but they do make a big thing about how their microphone is 'omnidirectional' compared with the more traditional directional designs. This is an interesting comment as the directionality of microphones in the ultrasound range is largely a function of their size and geometry, and that's a basic law of physics. They are understandably cagey about talking about their proprietry microphone technology, but we've spent a lot of time and effort on making microphones as omnidirectional as possible for our bat tracking arrays and have only ever managed it using multiple microphones on a single head and mixing the outputs, and this results in some really horrible phase responses which seriously affects the frequency response. I'd be interested to know how they did it.