Well I'm from the souf, but I live in Cleckheaton now. The notch filter can be used to reduce the "booming" of accordians and other instruments, to give a better balance to recorded sound, secondly, the battery inside (9v) pushes the mike to it's full power as some (mine inc) mini discs have a live output to the mike. This improves recording quality and volume.

If There's a chance of one coming from the states-batt box/notch filter then if some one lets me know, I'll check out the price with microphone madness.

By the way, do you get to the Cleck fok festival?

cheers.

Eric