2 Acoustical Spectrum Analyzer Apps Used by the Pros Alan Ogle, President and Gold Level Crestron programmer of LiquidLogix, Westminster, CO, weighed-in: I've used Pocket RTA and Real Time Analyzer on several occasions. Gets the job done, says Ogle. I use them to get a basic calibration of a room. Not every job though, but if it is a job that I am doing the DSP programming I will use it. It does a pretty decent job. Not the greatest mic on the iPhone but it works. Some of the apps have mic accessories that you can get which is more of a professional mic setup. Haven't used one of those yet. Using a mic accessory I can see this being a very useful tool, and inexpensive compared to some of the current RTA's. Right now I can't see using it to calibrate a home theater (I would use the calibration mic that some receivers come with now), but definitely for your standard conference room or training room. Thats it.