With the new legislation for maximum volumes for live events, you may find you need to ensure you keep under the legal limits. 10Eazy was developed y engineers to do just this. Enabling the FOH guy or gal to make sure they can get the most out of the PA without breaking the law.
The 10 Eazy system comprises of a measurement mic, USB mic preamp and software (which will run on fairly low powered machines) it can then provide a FOH display plus other interfaces for other production staff to check via the network.
The system costs around 2100 Euros, with a few notable endorsees - including Big Mick - FOH for Metallica - lets face it, if anyone needs it, its got to be him.