Measuring the frequency of a pitch?

Special Interest Groups Audio Processing
1

I am recording a sort of screaming/buzzing sound and I want to measure the frequency of the sound. How do I do so?

2

I can tell you the tools, but you may not get very far. Analysis > Spectrum Analysis. It usually tells you too much. The more rich, lush, and complex the sound is, the worse this display gets.

This is one (1) piano note from a grand piano. “G” as I recall.

http://kozco.com/tech/audacity/piano_G1.jpg

Each of those spikes contributes to the high, rich quality of the musical note. If that was a flute, you might have a fighting chance. Those produce far fewer spikes.

Koz

3

Koz, I am wondering why the decibel number in the spectrum are starting from negetive.
Is it related with using FFT for identify the frequency or soothing else.

Thank you

4

luke

see this ection of the Wikipedia article on dB: http://en.wikipedia.org/wiki/Decibel#.22Absolute.22_and_.22relative.22_decibel_measurements

Briefly 0 is being used as the maximum signal level you can recird digitally in Audacity without clipping occuring: −6 dBm means 6 dB less than 0 dBm

WC

5

<<<−6 dBm means 6 dB less than 0 dBm>>>

Or -6dBFS (dB Full Scale). There are conversions from dBFS to other technologies, but they depend on where you’re standing and what you’re doing.

Never content to leave things alone, even the digital measurements got a little fuzzy. That 400Hz tone you hear at the beginning of serious videos is -20 dBFS in US Broadcadst, -18 dBFS in Eutopean Broadcast and -12 -dBFS in home style DV. The absolute overload point of “Zero” fell to 32-bit floating digital techniques which, under some conditions allows you to get louder than zero.

Sound is such fun.

Koz