FreqCounter Problem

hello guys ,,
am trying to read a frequency for a sine wave signal and it's generating from Speakers (Audio Signal) so it's not a single sine wave signal,, on oscilloscope it's shown as multiple signals ..

the problem that when am trying to read the frequency for this signal it always gives me 0 :~
I am using the FreqCounter Library with the following code,,,, any suggestions for a solution:

#include <FreqCounter.h>


void setup() {
  Serial.begin(9600);                    // connect to the serial port
  Serial.println("Frequency Counter");
}

long int frq;
void loop() {

 FreqCounter::f_comp= 8;             // Set compensation to 12
 FreqCounter::start(100);            // Start counting with gatetime of 100ms
 while (FreqCounter::f_ready == 0)         // wait until counter ready
 
 frq=FreqCounter::f_freq;            // read result
 Serial.println(frq);                // print result
 delay(20);
}

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tags added.

I suggest starting with the Example Program...
http://www.pjrc.com/teensy/td_libs_FreqCount.html

It probably won't do exactly what you want but I suspect it would be a good starting point.

I tried this before ..
I used FreCount , FreqCounter , FreqPeriod but I still have freq 0 :~ :~