/* this is the non-GTK version of gstring * String - Yet another Guitar Tuning Application * Copyright (C) 1998-1999 Sam Tannous * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * You should have received a copy of the GNU General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #include #include #include #include #include #include #include #include // in version 2.0 of FFTW, the following line was rfftw.h // this changed in version 2.1 because of the new RPM // I was using. #include static int cross=0, max1 = 0, max2 = 0; int fd; // Your frequecy resolution (smallest frequecy difference we can // detect), is simply f = sampling rate/number of samples // N is the number of samples we take each time we sample. // increasing this value will improve your freq resolution. // but if you make it too large, it takes longer to get each // sample. #define N 16384 // sampleing_rate is the sampling frequecy of the microphone...in Hz // lowering this value will lower f and improve your resolution. // But it will also limit the highest frequency you can detect... // ...remember the Nyquist rate: you must sample at twice the // highest frequency in order to prevent aliasing... int sampling_frequency = 22050; //int arg = 0x0002000a; int channels = 0; // mono=0, stereo = 1 int M = N/2; int N2 = N*N; // this is the default 8 bit format // you must use unsigned char for the data read (in[N]) int format = AFMT_S8; // this is for 16 bit samples. here, you must use // signed short //int format = AFMT_S16_LE; //signed short in[N]; int i; int a440 = 440; // f is the frequency resolution in Hz. It is commented and calculated // below. mycosine is just an array of cosine values used to improve // performance. float f, mycosine[N]; // delta is how far off we can be from a given note (changes with octaves) // before we say it is sharp or flat.. float delta; unsigned char in[N]; fftw_real freq,maxi,max, temp, in2[N], out[N]; rfftw_plan p; // this routing actually gets data from /dev/dsp... void get_data(void) { read(fd,in,N); for(i=0;i max) { max = temp; maxi = i;// * f; } } return; } void string_loop(void) { char label[128]; struct { char *label; float freq; } notes[] = { {"C ",65.406}, {"C ",130.81}, {"C ",261.63}, {"C ",523.25}, {"C ",1046.5}, {"C#",69.296}, {"C#",138.59}, {"C#",277.18}, {"C#",554.37}, {"C#",1108.7}, {"D ",73.416}, {"D ",146.83}, {"D ",293.66}, {"D ",587.33}, {"D ",1174.7}, {"D#",77.782}, {"D#",155.56}, {"D#",311.13}, {"D#",622.25}, {"D#",1244.5}, {"E ",82.407}, {"E ",164.81}, {"E ",329.63}, {"E ",659.26}, {"E ",1318.5}, {"F ",87.307}, {"F ",174.61}, {"F ",349.23}, {"F ",698.46}, {"F ",1396.9}, {"F#",92.499}, {"F#",185.00}, {"F#",369.99}, {"F#",739.99}, {"F#",1480.0}, {"G ",97.999}, {"G ",196.00}, {"G ",392.00}, {"G ",783.99}, {"G ",1568.0}, {"G#",103.83}, {"G#",207.65}, {"G#",415.30}, {"G#",830.61}, {"G#",1661.2}, {"A ",55}, {"A ",110}, {"A ",220}, {"A ",440}, {"A ",880}, {"A ",1760}, {"A#",58.270}, {"A#",116.54}, {"A#",233.08}, {"A#",466.16}, {"A#",932.33}, {"A#",1864.7}, {"B ",61.735}, {"B ",123.47}, {"B ",246.94}, {"B ",493.88}, {"B ",987.77} }; /* STANDARD FREQUENCIES (Hz) OF MUSICAL NOTES FOR INSTRUMENTS EXCEPT PIANO OCT # C C# D D# E F F# G G# A A# B 1 32.703 34.648 36.708 38.891 41.203 43.654 46.249 48.999 51.913 55.000 58.270 61.735 2 65.406 69.296 73.416 77.782 82.407 87.307 92.499 97.999 103.83 110.00 116.54 123.47 3 130.81 138.59 146.83 155.56 164.81 174.61 185.00 196.00 207.65 220.00 233.08 246.94 4 261.63 277.18 293.66 311.13 329.63 349.23 369.99 392.00 415.30 440.00 466.16 493.88 5 523.25 554.37 587.33 622.25 659.26 698.46 739.99 783.99 830.61 880.00 932.33 987.77 6 1046.5 1108.7 1174.7 1244.5 1318.5 1396.9 1480.0 1568.0 1661.2 1760.0 1864.7 1975.5 7 2093.0 2217.5 2349.3 2489.0 2637.0 2793.8 2960.0 3136.0 3322.4 3520.0 3729.3 3951.1 8 4186.0 4434.9 4698.6 4978.0 5274.0 5587.7 5919.9 6271.9 6644.9 7040.0 7458.6 7902.1 MIDDLE C IS C4 AT 261.63Hz, CONCERT PITCH IS A4 AT 440Hz. PITCH 1 2 3 4 5 6 7 8 G# 51.913 103.826 207.652 415.305 830.609 1661.219 3322.437 G 48.999 195.998 391.995 783.991 1567.982 3135.437 F# 46.249 97.999 184.997 369.994 739.989 1479.978 2959.955 F 43.654 174.614 349.228 698.456 1396.913 2793.826 E 41.203 92.499 164.814 329.629 659.255 1318.520 2637.020 D# 38.891 155.563 311.127 622.254 1244.598 2489.016 D 36.708 87.307 146.832 293.665 587.330 1174.659 2439.318 C# 34.648 138.591 277.183 554.365 1108.731 2217.461 C 32.703 82.407 130.813 261.626 523.251 1046.502 2093.004 B 30.868 123.471 246.942 493.883 1975.533 A# 29.135 77.782 116.541 233.082 466.164 987.767 1864.655 A 27.500 110.000 220.000 440.000 1760.000 73.416 932.328 69.296 880.000 65.406 61.735 4186.009 58.270 3951.066 3729.310 55.000 3520.000 */ int num_notes = sizeof (notes) / sizeof (notes[0]); // printf("string loop: \n"); get_data(); freq = maxi*f; sprintf(label,"i = %.0f freq = %.3f Hz",maxi,freq); /* change the delta as the freqency increases */ if (freq > 31 && freq < 63) delta = 2; if (freq > 63 && freq < 128) delta = 4; if (freq > 128 && freq < 192) delta = 8; if (freq > 192 && freq < 256) delta = 12; if (freq > 256 && freq < 384) delta = 16; if (freq > 384 && freq < 512) delta = 24; if (freq > 512 && freq < 1024) delta = 32; if (freq > 1024 && freq < 2048) delta = 64; if (freq > 2048 && freq < 4096) delta = 128; if (freq > 4096 && freq < 8100) delta = 256; for (i=0; i < num_notes; i++) { if (abs(notes[i].freq - freq) < delta/2) { if (abs(notes[i].freq - freq) < (f/2.0) ) sprintf(label,"i = %.0f reference freq = %.3f Hz actual freq = %.3f Hz note = %s", maxi,notes[i].freq,freq,notes[i].label); else if (notes[i].freq < freq) sprintf(label,"i = %.0f reference freq = %.3f Hz actual freq = %.3f Hz note = <--%s", maxi,notes[i].freq,freq,notes[i].label); else if (notes[i].freq > freq) sprintf(label,"i = %.0f reference freq = %.3f Hz actual freq = %.3f Hz note = %s-->", maxi,notes[i].freq,freq,notes[i].label); } } if (max > 10000000000) { printf("%s\n",label); // printf("max = %f temp = %f\n",max,temp); } return; } int main(int argc, char *argv[]) { // save these values so we don't keep recalculating them for each sample // if an A440 does not really give you 440 Hz, then you probably // need to change the following line a little. Run the program // and use an A440 Hz tuning fork. The program will tell you what // value 'i' is on the line. f = 440.0/i; f = (float) sampling_frequency/N; // we store an array of cosine values to improve preformance. for(i=0;i