How to find the frequency of a sound file using fft on matlab?

Hello i have multiple sound recording which I need to find the frequency of, how can i do this using fft and matlab, how do i get the frequency by uploading the file?

Please help! Thank you!

[Birdman]

Can you share your sound file in a mat file?

[Walter Roberson]

Is the sample frequency known? If not is there any component of known frequency, such as a known 10 Hhz sine tone present?

[ali sabbah]

Hi, no there is no frequency known. Basically all i want to do is, put this audio file on matlab and using fft i want to get the frequency, i do not know anything about inputs

[ali sabbah]

Any solutions fellas?

[Walter Roberson]

There is no possible solution to this. When all that is available is the data, then it is absolutely impossible to tell the difference between a 10 Hz sine wave recorded at 20 samples per second, compared to a 20000 Hz sine wave recorded at 40000 Hz.

Now, if you happened to know that the data represented human speech, then it would be potentially possible to estimate the sampling frequency. But this gets into the category of having a component of (approximately) known frequency, which you indicated earlier is not your situation.

Answer 1

[Walter Roberson]

Sorry, unless you have something known about the data, then it is not possible to determine the frequency. For example, the data for a 10 Hz tone for 5 seconds is exactly the same as the data for a 5 Hz tone sampled for 10 seconds.

If the data is in the form of an audio file such as an mp3 file, then those have a sampling frequency recorded in them that can be used to analyze the data. However, if you just have raw data there is nothing you can do.

[Hamza Ashraf]

i have an audio data recorded as wav file i want to find its frequency. how can i do it please help me out

[Walter Roberson]

When you audioread() then the second output is the sampling frequency.

If you want to know the frequency of the speech content then that varies from millisecond to millisecond; you should consider something like spectrogram()

[Hamza Ashraf]

yes i tried spectrogram() and it gives the frequency plot but i want to extract the signle value of frequency of the audio data. is there any way to do that. please do share the code am new to matlab dont know much how to do things. the audio data is actually the siren of ambulance i want to calculate it frequency

[Walter Roberson]

The ambulance is moving. Because of the Doppler effect, the frequency of the sound will not be a single constant, not even if the siren is a pure sine wave. Ambulances seldom use pure sine waves.

[Hamza Ashraf]

oki thank you i understand that. can you tell me how to measure dopler of the sound from the mic? i want to do comparison between siren of ambulances at different distances from mic(sound capturing device).

[Walter Roberson]

https://www.mathworks.com/help/phased/ug/doppler-effect-for-sound.html