If the signal is not distorted, the sampling frequency should be >100%; = 2 times the highest frequency of the signal.

In other words:

For example, if the highest frequency of the signal is f= 1khz (I don't remember what the highest frequency of speech is, this is just an example), then the sampling frequency is at least 2khz.

If the highest frequency of the signal is 2khz, the sampling frequency should be at least 4khz.

This should be clear.

If the sampling frequency is too low, the high-frequency signal will be lost, which can be said to be a treble, but it is not lost. It's not that the high notes are silent, but that the high notes are out of tune, understand?

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Who will specialize in that kind of software? Oh, that's boring!

But there are other softwares to try.

I remember there used to be an audio compression software that could compress music in various formats.

It's just a piece of CD-quality music, which can be compressed into wma, rm…… and other formats. The principle of his compression is to reduce the sampling frequency.

Because some websites require uploading the size of music, that kind of software is used to help music files "slim down". I pressed it, and the effect is really different. The worst effect is the same as the sound quality of a mobile phone. Because of the low sampling frequency, we can only hear each other's voice and tell who it is, but it is not pleasant to the ear. CD-quality music sampling is very pleasant and should be experienced.

I don't remember the exact name of that software. The software I played a few years ago ...

Actually, there is no need to find that software.

If you really want to listen to the changes after the sampling frequency is reduced, there is a simple way: first, play the music on the stereo, then let someone call you from your home mobile phone, and then listen to the music in the mobile phone again, and you will know the effect.