Coherence Tuner

This app uses a revolutionary tuning engine to detect and measure the pitch of multiple notes at the same time.
This tuning mode uses the built-in microphone and is as accurate as any strobe tuner! 
It is quick, stable, simple to use, and fully polyphonic - just start the app and strum or pluck individual strings for an instant read. 
It has auto gain control, auto noise elimination, and while it allows for a couple of optimization settings to be made, is as plug-and-play as it gets!
It uses an advanced multi-mode display that simultaneously shows tuning information for all strings at once in a clear and unambiguous presentation.
The tuning engine operates over a wide range of frequencies - with a simple indicator for regular tuning, and a highly precise wave tuning overlay to deliver pitch perfect response - equivalent in accuracy to the best strobe tuners.
In addition to the standard 6-String Guitar tuning, additional tunings include:
• E Flat, D, Drop D, Double Drop D, DADGAD, Open D, Open E, Open G
Stay tuned (pun intended) for future updates as we plan to add more tunings over time.
Additional instrument support includes:
• 7-String Guitar, Violin, Viola, Cello, 4-String Bass, 5-String Bass, 6-String Bass, Ukulele, and 5-String Banjo.
The tuner is configurable to select the reference frequency for tuning in a range 435Hz to 445Hz - with a default of 440Hz.
The engine can also be configured to tune using either the string Fundamental or its Second Harmonic - maximizing the range of instruments and frequencies that can be covered.
(Some instruments have a stronger second harmonic than the fundamental. Additionally, instruments that operate in the bass range can often benefit from being tuned to the second harmonic. However, where possible, we recommend tuning using the fundamental as it delivers better accuracy.)
How it works:
Pluck strings on your instrument and the appropriate needles will respond showing coarse tuning. As you get closer to pitch, a wave overlay will automatically be displayed that shifts left or right depending on your pitch.
When you reach the exact pitch, the wave is stable.
Simple as that!