Sound frequency counter.

alec_t · Sep 21, 2012

I've re-done the sim using as input a wav file of a nylon-stringed acoustic guitar playing E3 (165Hz).
Interestingly, it looks like the thing that would screw up the frequency counter is more likely to be the initial transients as the string is plucked, rather than any harmonic content. So the counter reading during the first ~200ms of the note should be ignored.
Although the harmonics affect the wave shape they seem to have little effect on the interval between zero-crossings of the waveform (which is what the counter would measure).

ikelectro · Sep 21, 2012

cowboybob said:
All well and good, audioguru. Thank you.

But, if a string is plucked, in the tuning process, without any interference, and it is at precisely the note sought, it will resonant properly and without harmonics. I have been going on the assumption that the OP wished to use his counter for tuning purposes.

The counter will, of course, give wildly fluctuating readouts until the proper, single frequency for the key he is tuning for is reached. But once tuned correctly, it will display the right frequency, whether or not the signal to it is clipped.

Now, if the OP meant he wished to see whatever frequency(s) are being played, regardless of finger on string manipulations or plucking positions, then, yes, of course, the harmonics will abound and with or without the clipping effect of the preamp the counter will be over whelmed and display gibberish.

In the above example, I can't think of any situations where any counter could suffice for the OPs needs and equipment on hand. A spectrum analyzer, yes. But not a counter.

i want to tunning the guitar. so i want ot go with the " a string is plucked".

ikelectro · Sep 21, 2012

View attachment 67394
so I have these mic for my input.

audioguru · Sep 21, 2012

The guitar wave file is an acoustic guitar playing a low frequency where the body of the guitar resonates, reducing harmonics levels. Its second harmonic is obvious on a real time analyser and the third and higher harmonics are pretty darn low.

The new .asc file about overdriven is taking a long time to do something so I gave up waiting.

I found a guitar tuner project that has AGC (to avoid clipping?).

I have never seen a mic that looks like that. A modern very inexpensive but high quality electret mic looks like this and is connected with a shielded audio cable, not just two ordinary wires:

Mr RB · Sep 22, 2012

audioguru said:
...I found a guitar tuner project that has AGC (to avoid clipping?).
...

Also because the sound decreases constantly after being plucked.

audioguru said:
...
I have never seen a mic that looks like that. A modern very inexpensive but high quality electret mic looks like this and is connected with a shielded audio cable, not just two ordinary wires:

Yeah they look like cheap dynamic (magnetic) mics ie from telephone handsets or similar.

Re the harmonics if you pluck the string with a soft finger instead of a nail or pick you get a lot less harmonic content.

Either way if designing a tuner I would try to add a low pass filter to try to get more of the main fundamental freq. You can also do some in software is using a PIC, my project for decoding DTMF tones with a PIC used a
"debounce" style timer where the input has to be Hi for XuS before recording an edge, that can ignore a lot of the harmonic content and a guitar wave (where the harmonic is weak) will be many times easier than a DTMF wave where both sines are the same amplitude;

**broken link removed**

Sound frequency counter.

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Sound frequency counter.

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