DSP effects: guitar tuner and wav2midi ?

yastreb

I found recently this forum and installed kx drivers. Now I am playing with sound effects. I wounder if it is difficult to implement following two DSP effects:

1) "guitar tuner". The idea is to analyze the ingoing sound and determine its dominant frequency. Than this frequency is compared to frequencies of standard notes and the output explains in which direction one should adjust the frequency of ingoing sound to make it perfectly tuned. Well, it's preferable to put a level meter or an arrow, which shows how much the frequency is wrong. If it is difficult to implement, in the output it is sufficient to put the difference between the exact frequency and the "wrong" one multiplied by some factor, so that high pitch means that one should decrease the freq. and vice versa.

The main frequency can be defined as the highest harmonic in Fourier spectrum of the sound. There should be standard implementations of fast Fourier transformation. Frequencies of standard notes are also known that are 440 Hz (A/"la" note) and other notes are generated by multiplying this frequency by 2^(1/12), so that by adding 12 half-tones the frequency changes by a factor of 2 (i.e. that's an octave).

2) "wav2midi" If it is realistic to determine reliably the frequency of the incoming sound, it would be really great to substitute the original sound with some midi signal of a same frequency and through it to the output! Imagine, that one plays a guitar, but the sound is the one of a flute or a church organ!

Russ

The DSP has only limited resources which makes such things impractical (if not impossible).

Your best bet would be to implement such things in software (VST, etc).