A free app for Android, by Pragmatheorist.

The best real-time audio spectrum analyzer for professionals and sound enthusiasts.

With Audizr, you can monitor the sound frequency content of your home studio speakers or a PA system with a greater accuracy than a human ear could ever reach.

If you have a new, you can use your smartphone or tablet to capture the sound and upload it to the server for analysis. If you are planning to buy new equipment, you can check the sound spectrum for your current devices, compare the results, and choose what you think is the best option for you.

Audizr is an app that is optimized by professionals for accuracy and stability.