I am new to signal processing and I am unable to understand the concept of sampling frequency. This YouTube video presents 20Hz to 20kHz (Human Audio Spectrum) frequencies. When I reach the poisition of 8000Hz its a very sharp sound. On the other hand when I listen to these 16-bit PCM wav file which has a sampling frequency of 8000 Hz they sound is appears to me on a much more lower note. Why is the difference when both have the same frequencies?
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$\begingroup$ Please clarify your question. What's the exact-content of the 16-bit PCM file? How do you listen to it. I just do not want to blindly assume things... $\endgroup$– Fat32Commented Jul 22, 2023 at 19:22
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$\begingroup$ I have provide the link. These are random english utterances. $\endgroup$– Turing101Commented Jul 22, 2023 at 19:32
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2 Answers
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When you play back a soundfile (that was sampled at 44.1 kHz) at a lower sample rate (like 8 kHz), that is not the same as resampling the audio to the lower rate. It's just like slowing down a vinyl record or analog tape. Sounds will be lower in pitch and slower in development, tempo, and change.
answered Jul 22, 2023 at 20:20
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Sampling rate is the frequency or rate at which samples of analog signal is converted to digital. For example CD audio is sampled at 44100 Hz.
But as you likely know, the content of the sampled audio can be anything such as low bass frequencies or birds chirping, the sampling rate defines how high frequencies can be sampled and played back.
That's why CDs sampled at 44100 Hz can convey nearly full human audio hearing range up to 20 kHz and that's why old landline telephones sampled at 8000 Hz sound muffled because it can only convey frequencies less than 4000 Hz.
