Demo Video: http://youtu.be/G29DOVl1fAo
Spectral Eye Pro is an enhanced version of our free app, Spectral Eye. If you are unfamiliar with the app, we suggest trying Spectral Eye first, to make sure that this is what you need. If you like the free version, you can upgrade to the paid version later!
Spectral Eye Pro analyzes incoming audio signals to extract the underlying frequencies. Most sounds are built up from a variety of sine waves; a simple whistle might be a single wave, while a guitar, piano, or the human voice have many waves added together.
By using a Fast Fourier Transform, sound can be decomposed into each frequency. Normally, this information is displayed on a chart, and there are number of excellent apps that do exactly this. Spectral Eye Pro rearranges the FFT into a spiral, so that frequencies that are an octave apart are lined up as rays from the center of the display. The strength of each frequency is represented by the size of a red circle.
Play music, and Spectral Eye Pro will reveal the frequencies. For a guitar, it's easy to see that in addition to the root frequency of a note, there are also a number of harmonic frequencies -- and these change based on the strings used, the pickups, and the amplification system. It's the frequencies present in the notes that make a Telecaster sound different from a Les Paul, and a piano different from a trumpet. Play an instrument, music from your iTunes library, or have it listen to whatever sounds are nearby -- the display is fun to watch.
If you're interested in understanding the nature of sound, use Spectral Eye to get a better view. There is a free version of this app, which was created as a utility used in the development in other Secret Base Design apps.
The Pro version supports both input, filter, and output slots on Audiobus, so that you can directly analyze the freqencies produced by other synthesizer apps. For synthesists looking to create new sounds, or understand what they are hearing, Spectral Eye is an invaluable too.
The pro version also supports Virtual and Core MIDI; you can see the frequencies of sounds around you, and then play along with them using the novel Spectral Eye interface. If you don't have perfect pitch, you can use Spectral Eye to transcribe melodies that you hear or compose on your own.
*** Note -- we cannot respond directly to reviews in the iTunes store. If you have trouble with the app, please contact us by email, Twitter, or Facebook. We're happy to help, and as mentioned, have a free version of the app to make it possible to evaluate without making a purchase.
To directly analyze audio directly from other apps (synthesizers, drum machines, and so on), simply connect to Audiobus. This is shown in the demo videos. To analyze sound from an MP3 file, you can use an app which imports audio, and then streams it over Audiobus. Audioshare is one such app, and we recommend it highly.
Updated for iOS 7 and the new Audiobus library.