Audio Tuner from Supernifty used the iPhone as a portable aid for checking an instrument’s pitch. The original March 20, 2009 article describes three central features: spectrum analysis, a pitch pipe and built-in tunings for different instruments.
Listen, compare, adjust
The documented workflow starts with playing a note into the phone’s microphone. The app indicates whether the sound is flat or sharp, while a tone generator provides a reference note to compare by ear. The spectrum view offers a visual picture of the sound alongside that tuning task.
The archive establishes this basic approach, but does not provide a measured accuracy test or an exhaustive list of supported tunings. Its promotional promise of perfect pitch should not be treated as a technical accuracy specification.
Get a clearer reading
For a microphone-based tuner, work in a quiet place and play one steady note at a time. Let the initial attack settle before reading the display, then repeat the note after a small adjustment. Nearby conversation, other instruments and a fading note can make a reading harder to interpret.
Check the intended note and octave as well as the sharp-or-flat indicator. A stable reading is useful only when it corresponds to the string or pitch you mean to tune. An audible reference can also help develop the connection between what the display says and what you hear.
These are general tuning suggestions rather than results from testing the archived app. The preserved entry documents Supernifty’s early iPhone product; current availability and device compatibility have not been verified.