Capturing live recordings via the audience is very, very difficult. It's a true craft. Microphone placement is only the beginning of it. Knowing the configuration of the microphones if using more than one. Knowing the rest of the equipment. Knowing the venue, it's gear, and its acoustics. I listen to a lot of live recordings, and it is not an easy thing to master.
If the goal is to capture the atmosphere, as well as the sound, it's sometimes best to create what is known as a Matrix. It's a combination of a recording off the soundboard, or mixer, coupled with a microphone/audience recording (sometimes more than one, if more than one is available, because each microphone is better at collecting sound from particular ranges). And it is not an easy task in itself. Phasing, pitch matching, and all kinds of little technical nuances have to be aligned for it to not sound like a mess. Sure, you can throw one over the other in Audacity, but you can usually tell that is exactly what happened.
And I'm not talking some lofty, studio-grade expectations. There are a few hobbyists out there who are masters at this. I mention these things because I would think it particularly difficult to get a high-quality live recording from a noise or power-electronics group. A simple soundboard recording wouldn't be difficult at all, but to capture room atmosphere would be almost Herculean.
If you're interested in microphones, live recordings, and more technical babble than you can stand, check here:
http://taperssection.com/index.php
