Spectral Eye 4+

Secret Base Design

Designed for iPad

    • 5.0 • 72 Ratings
    • Free



The sound that you hear is made up of vibrations at different frequencies. Two instruments, such as a guitar or a trumpet, might play the same note -- what makes them sound different are the harmonic frequencies that combine to make the overall tone.

Spectral Eye will reveal these frequencies, so you can see what your sounds are made from. Using a Fast Fourier transform, incoming sound is split into individual sine waves, which are then displayed on the screen. Frequency spectrum displays are not uncommon; what makes Spectral
Eye different is the arrangement of the frequencies into a spiral, so that octaves line up as rays coming from the center.

The `concert pitch' of A is a vibration at 440 cycles per second. One octave above this is a doubling to 880, and an octave below is 220. On the Spectral Eye display, these frequencies fall into a line. You can see the structure clearly on the display as you make different kinds of sounds or play music. The stronger the frequency, the larger the red dot and white line; the size of the dots on the display scale to show the relative
frequency strengths clearly.

When you pluck a string on a guitar, the string will vibrate at a root frequency, but also at a frequency that is twice that of the root, as well as a number of different multiples. The resonant frequencies are what make different guitars sound unique. Harmonies between the frequencies of multiple notes are what make chords sound interesting. As the tone
of a synthesizer note changes, you can see different component frequencies rise and fall.

In addition to displaying the frequencies, you can also generate sound using Spectral Eye; we have included a simple synthesizer, which will generate either a pure sine wave, or a sine wave with an additional frequency a fifth above. Move the control on the right or bottom
part of the screen to change the tone, and touch the main display and move in a clockwise or counterclockwise manner to change the pitch.

The version of Spectral Eye also includes MIDI; you can start a MIDI synthesizer, and then use the Spectral Eye display to trigger notes. There are dozens of excellent synthesizers available; you can use this app to not only play them, but to see how their sounds are formed. And if you're trying to pick out the notes to a song, you can watch the display to see where the notes land.

Spectral Eye is free, and will remain that way. No pop-up ads. No nag screen. Just good clean fun. If you like the app, we would very much appreciate a review in the app store. The core technology in Spectral Eye is part of our polyphonic pitch-to-MIDI app MIDImorphosis, which will let you use an ordinary guitar or other instrument to control MIDI synthesizers. This technology is also part of Infinite Looper, our innovative MIDI looping app. We have a number of other music-related apps available; we hope you dig Spectral Eye, and if you want to help us keep good things going, reviews or purchases of our other apps would be awesome!

What’s New

Version 2.0

This app has been updated by Apple to display the Apple Watch app icon.

MIDI support added.
Updated for iOS 10.

Ratings and Reviews

5.0 out of 5
72 Ratings

72 Ratings

needHymn ,

Dear Dev, can you make this open source?

I wish this, exactly this, was included in every synth. Because trying to recreate a specific sound using pretty much any synth is soooo much more difficult without a spectrum analizer such as this. But it's fairly rare to find any on the app store that actually show the notes, and the octives, in such an easy layout such as this.

But I mainly came here to say, that it's 2020. Audiobus 3 is here. Auv3 is here too. Add some ios versions later, and sadly, this app kind of only works with the mic now.

If you launch it with AUM... Well... It doesn't launch at all. AUM gives an error and suggests you try again. And if you launch it with Audiobus 3, it actually launches, but it receives no audio from Audiobus... It just continue to receive mic, and Audiobus thinks this app is "asleep".

So I'm still using it, with just the mic. I play back audio through my phones speaker, lol. Not ideal, but it's still the best, and it's free.

This app needs to be updated, but maybe the dev doesn't have time. Any chance it could be released as open source? Then maybe someone else would be willing to update it, to keep it functioning fully?

Kristal of Hummingbird Studios ,

Super diversely useful

Awesome, nothing else comes close, and yet it's free. This is the go to app for tuning your whole guitar in one strum, examining your chords, and practicing polytone singing. Because you can see the weight of each note, you can get a good idea why your sound is going wrong in spite of supposedly being in tune. It's additional features are cool and useful too.

If you work in microtonal instruments like slide guitar or need to figure out what's really going on when multiple notes are playing, but in terms of music theory, not just frequency numbers, and would like to visualize it, this is the app to use.

NoahSpurrier ,

Fun and useful

So, right off, this is almost the best guitar tuner I’ve used. If it would show the octave number of a note that would be very useful. Not strictly necessary assuming the strings aren’t totally out of tune, but it would be handy for full restringing.

I get that the red dot at the bottom lets you adjust the number of components of the output as you slide it left and right, but moving it up and down does something to the volume I think, but only got the current note. Not sure this feature adds much.

App Privacy

The developer, Secret Base Design, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

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