An iOS app that could be useful to sort out noises when fine-tuning on set equalization, notch filters, and so forth.
(I'm sure there an applications for Android OS as well)
"Spectrum Analyzer for iOS is a powerful real-time audio analysis app. Designed with musicians and recording engineers in mind, it can also be used by anyone interested in the world of sound. Ideal for room tuning or speaker tuning, the app enables portable, precision audio measurement and visualization."
Available from Onyx (search the app store for Spectrum Analyzer)