Index: apps/plugins/pitch_detector.c
===================================================================
--- apps/plugins/pitch_detector.c	(revision 22691)
+++ apps/plugins/pitch_detector.c	(working copy)
@@ -178,6 +178,38 @@
     float2fixed(0.50),
 };
 
+#define DEFAULT_REFERENCE 5 /* 440 */
+/* log of Frequency of A normalised to 440Hz */ 
+const fixed lfreq_A_table [] =
+{
+	float2fixed (-0.016488123),  /*435 Hz */
+	float2fixed (-0.013175389),
+	float2fixed (-0.009870244),
+	float2fixed (-0.006572654),	
+	float2fixed (-0.003282584),
+	float2fixed (0),			/* 440 Hz reference standard A */
+	float2fixed (0.003275132),
+	float2fixed (0.006542846),
+	float2fixed (0.009803175),
+	float2fixed (0.013056153),
+	float2fixed (0.016301812),  /* 445 Hz */
+};
+/* Frequency of A normalised to 440Hz */
+const fixed freq_A [] =
+{
+	float2fixed (0.988636364),
+	float2fixed (0.990909091),
+	float2fixed (0.993181818),
+	float2fixed (0.995454545),
+	float2fixed (0.997727273),
+	float2fixed (1),
+	float2fixed (1.002272727),
+	float2fixed (1.004545455),
+	float2fixed (1.006818182),
+	float2fixed (1.009090909),
+	float2fixed (1.011363636),
+};
+
 /* How loud the audio has to be to start displaying pitch  */
 /* Must be between 0 and 100                               */
 #define VOLUME_THRESHOLD (50)
@@ -279,6 +311,7 @@
     unsigned sample_size;
     unsigned lowest_freq;
     unsigned yin_threshold;
+	unsigned freq_A;
     bool use_sharps;
     bool display_hz;
 } tuner_settings;
@@ -325,6 +358,7 @@
     settings->sample_size = BUFFER_SIZE;
     settings->lowest_freq = period2freq(BUFFER_SIZE / 4);
     settings->yin_threshold = DEFAULT_YIN_THRESHOLD;
+	settings->freq_A = DEFAULT_REFERENCE;
     settings->use_sharps = true;
     settings->display_hz = false;
 }
@@ -426,6 +460,23 @@
     { "0.50", -1 },
 };
 
+/* These are the display frequency options for note A */
+
+static const struct opt_items freq_A_text[] =
+{
+	{ "435", -1 },
+	{ "436", -1 },
+	{ "437", -1 },
+	{ "438", -1 },	
+	{ "439", -1 },
+	{ "440", -1 },
+	{ "441", -1 },
+	{ "442", -1 },
+	{ "443", -1 },
+	{ "444", -1 },
+	{ "445", -1 },
+};
+
 static const struct opt_items accidental_text[] = 
 {
     { "Flat", -1 },
@@ -469,6 +520,7 @@
                         "Accidentals",
                         "Display Frequency (Hz)",
                         "Reset Settings",
+						"Frequency of A(Hz)",
                         "Quit");
 
     while(!done)
@@ -518,7 +570,18 @@
                                &reset,
                                BOOL, noyes_text, 2, tuner_settings_reset_query);
                 break;
-            case 8:
+			case 8:
+                rb->set_option(
+                    "Frequency of A(Hz)",
+                    &tuner_settings.freq_A,
+                    INT, freq_A_text, 
+                    sizeof(freq_A_text) / 
+                    sizeof(freq_A_text[0]), 
+                    NULL);
+                break;
+
+
+            case 9:
                 exit_tuner = true;
             case 0: 
             default:
@@ -708,25 +771,28 @@
     if (fp_lt(freq, FP_LOW))
         freq = FP_LOW;
     lfreq = log(freq);
-
-    /* Get the frequency to within the range of our reference table */
-    while (fp_lt(lfreq, fp_sub(lfreqs[0], fp_shr(LOG_D_NOTE, 1))))
+	fixed lfreq_A_offset;
+	/* This calculates a log freq offset for note A */
+	lfreq_A_offset=lfreq_A_table[tuner_settings.freq_A];
+    /* Get the frequency to within the range of our freq_A table */
+    while (fp_lt(lfreq, fp_sub(fp_add(lfreqs[0],lfreq_A_offset), fp_shr(LOG_D_NOTE, 1))))
         lfreq = fp_add(lfreq, LOG_2);
-    while (fp_gte(lfreq, fp_sub(fp_add(lfreqs[0], LOG_2), 
+    while (fp_gte(lfreq, fp_sub(fp_add(fp_add(lfreqs[0],lfreq_A_offset), LOG_2), 
            fp_shr(LOG_D_NOTE, 1))))
         lfreq = fp_sub(lfreq, LOG_2);
     mldf = LOG_D_NOTE;
     for (i=0; i<12; i++) 
     {
-        ldf = fp_gt(fp_sub(lfreq,lfreqs[i]), FP_ZERO) ? 
-                 fp_sub(lfreq,lfreqs[i]) : fp_neg(fp_sub(lfreq,lfreqs[i]));
+        ldf = fp_gt(fp_sub(lfreq,fp_add(lfreqs[i],lfreq_A_offset)), FP_ZERO) ? 
+                 fp_sub(lfreq,fp_add(lfreqs[i],lfreq_A_offset)) : fp_neg(fp_sub(lfreq,fp_add(lfreqs[i],lfreq_A_offset)));
         if (fp_lt(ldf, mldf)) 
         {
               mldf = ldf;
               note = i;
         }
     }
-    nfreq = freqs[note];
+	/* this scales the calulated note by the freq offset for note A */
+    nfreq = (fp_mul(freqs[note],freq_A[tuner_settings.freq_A]));
     while (fp_gt(fp_div(nfreq, freq), D_NOTE_SQRT)) 
         nfreq = fp_shr(nfreq, 1);
     while (fp_gt(fp_div(freq, nfreq), D_NOTE_SQRT))