The HotPaw iChromatic Strobe Tuner is an iPhone application which uses
the built-in microphone on your iPhone to allow you to tune a musical
instrument via visual displays.  It includes both a frequency readout
and 3 highly accurate and responsive waterfall strobe panes which
allows extremely precise tuning.  When the waveform patterns line up
vertically as well as stop moving sideways in the strobe panes, this
indicates that the input pitch (or a strong harmonic of the base pitch)
matches an equal temperament on-pitch frequency.

With the waterfall strobe tuning window, even very slight differences in
frequency between the pitch which the microphone detects and the target
pitch will cause the abstract waveform to waver or move sideways as it
cascades down the strobe window.

The top strobe pane is filtered to reject background noise.  The second
pane allows simultaneous viewing of a selected harmonic.  The bottom
pane is running at half the detected frequency to allow viewing of the
1st subharmonic.

Also included is a pitch frequency readout in Hz and cents.  Configuration
options include a Concert A reference frequency adjustment.

Please try the free inTuna A440 application first to see if you appreciate
the advantages of using a strobe tuner.

Tuning range using the built-in iPhone microphone is from 2 octaves
above middle-C to 2 octaves below. Use with an 2nd generation iPod Touch
requires an external microphone.

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Manual mode allows you to lock the strobe tuner to a particular pitch.
When first enabled, it locks to the current pitch being used by automatic
pitch selection.  You can adjust the selected note by the note up/down,
and octave up/down buttons.

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In manual mode, you can adjust the frequency used by the strobe for each
note by using a custom intonation table.  This allows for either custom
intonation, or piano stretch tuning.

You can download a custom intonation text file from the internet by
entering a URL for your table.  The file should be plain text.  The table
can be embedded in a web page containing other html, as long as the table
itself is embedded in plain text format.  The actual table starts after
the keywords:

"IntonationTable:", 
without the quotes, and ends with the keyword 
"EndIntonationTable".
The intonation table is a 2-column csv file.  The first column is the midi
note number, second column the cents offset to be used for that note.
Any addition items (note names, etc.) on the same line are considered
comments when downloading the file.

In manual note select mode, you can also adjust the per-note cents offset
on-the-fly, or as you tune, by tapping on the strobe windows.  Tap on
one side to adjust the pitch offset up, and the other side for down.
Tap the bottom strobe to zero the offset for that note.

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Version information:

Version 1.3.1

iPhone 3GS performance enhancements and OS 3.0 compatibility improvements.
Useful frequency range has been slightly increased on 3G and 3GS devices.

Version 1.2.0

Added a manual note selection mode to reduce the effects of noise
interference seen when using automatic note selection mode.  Changed the
second strobe pane to view a selected spectral harmonic (2nd thru 5th).
This allows simultaneous strobe viewing of a pitch frequency and one of
its harmonics.

Added the ability to download and email a custom intonation/stretch table
(cents offset on a per note basis).  You can also now tap on the strobe
in manual mode to customize the intonation/stretch table as you tune.

Version 1.0.0  

Initial release


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Copyright 2009 HotPaw Productions , All Rights Reserved
No Warranties of any kind expressed or implied.
http://www.hotpaw.com/intuna 
DSP code Copyright 2009 Ronald H Nicholson, Jr
Artwork by LizDesigns
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