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<H2>Pitches and Frequencies</H2>
The Pitch<A NAME="1"> object</A> provides a generalised mechanism for expressing and
converting between various pitch and frequency formats. The formats
supported are as follows:
<P><UL><LI><CODE><EM>value</EM> Hz</CODE> (cycles per second, analogous to Csound's cps notation);
<LI><CODE><EM>octave</EM>.<EM>semitone</EM></CODE> (analogous to Csound's pch notation);
<LI><CODE><EM>octave</EM>.<EM>decimal</EM></CODE> (analogous to Csound's oct notation);
<LI>note name notation (the pitch is represented as a character string).
</UL>
<P>In the last case the pitch names <CODE>C-G</CODE> can be used followed by an
optional <CODE>b</CODE> for flat or <CODE>#</CODE> for sharp. The basic pitch
name of the note is then followed by an octave number (whose value
has the same meaning as the integer parts of the <CODE>pch</CODE> and
<CODE>oct</CODE> notations).
Finally an optional microtonal adjustment may be added in the form of a
fraction <CODE>+<x>/<y></CODE> or <CODE>-<x>/<y></CODE>
which adds/subtracts a fraction of a semitone to/from the pitch given.
Some practical examples are given below:
<P><PRE>
Pitch p1 = 110.5 Hz;
Pitch p2 = C#5+1/2;
Pitch p3 = 8.05 pch;
Pitch p4 = 6.1764 oct;
</PRE>
<P>Pitch methods include:
<P><DL><DT><B>asPitch()</B><DD>
returns a number representing the pitch converted to pch notation;
<DT><B>asOctave()</B><DD>
returns a number representing the pitch converted to oct notation;
<DT><B>asFrequency()</B><DD>
returns a number representing the pitch converted to a frequency;
<DT><B>asName()</B><DD>
returns a character string representing the name of the pitch.
</DL>
<P>
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<tr><td colspan="3" class="addr"><!-- bottom panel --><ADDRESS><FONT SIZE=-1>©1999,2000 Mark Pearson
<A HREF="mailto:m.pearson@ukonline.co.uk">m.pearson@ukonline.co.uk</A> April 30, 2000</ADDRESS><BR></td></tr><!-- end bottom panel --></table></BODY></HTML>
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