> Something vibrates, - it makes the air vibrate, - the air vibrates the sensitive bones in your ear, - and this sensation is registered in your brain as sound.
> Things that vibrate fast are sensed as being high-pitched, and things that vibrate slowly are low-pitched. Things that make big vibrations are loud, and so on. These vibrations can be graphically represented by a waveform.
If you heard this sound, it would be a clear solid note like that made by a tuning fork. A higher pitched note would have more cycles in the same amount of time etc.
When sound is digitised, the waveform is reconstructed by measuring the voltage (the y axis) thousands of times a second and storing this reading in computer binary. When you record audio on your pc or when you save or listen to audio files, you may notice that the audio has two properties: bits and sample rate. The most common of these is 16bit 44.1Khz audio as found on CDs. But what do these numbers actually mean?
Bits (or Binary digits). In audio, it's very similar to your monitor display settings, as it's the amount of different voltages (amplitudes) that can be sampled. So, just as 8bit video only has 256 colours, 8bit audio only has 256 different amplitudes it can sample.
16-bit sample means that for one snapshot of audio, 16 bits (or 2 bytes of memory) are used to record the data.
A "sample" is supposed to tell you how "high" or "low" the volume of a wave is at that instant. Mathematically, a 16-bit sample allows you to read that volume level with a choice over 65,000 different values. That's a lot. But the human ear's ability goes beyond that.
24-bits (3 bytes of memory) can read/record nearly 17 million values. This is more in the neighborhood of the human ear's capability.
In other words, with 24-bit samples at 44kHz sampling rates, you can pretty much reproduce a sound so accurately that the human ear can't tell the difference.
Sample Rate is very simple as it's the amount of times every second that the audio is sampled or given a binary number. CDs are sampled at 44.1KHz or 44,100 times a second. The sampling rate tells how often a digital "snapshot" is taken of audio. Just like resolution in a photo, the more "dots per inch", the more dots you have representing that inch of photo, thus higher resolution. The computer is taking 44,100 snapshots of your audio per second.
Make a decision
A lot of sound cards can operate at 96kHz, 32 Bit. So we have to consider the load on your CPU & hard drive.
Now where do we find the balance in choosing a sample rate?
A sample rate of 44kHz allows you to record frequencies up to 22kHz, and that is the top of human hearing range. So 48 KHz, 24bit is just fine for most home studio recordings.
Now the choice is up to you, according to the standard you're trying to attain, and the capabilities of your PC.
Secondly, the frequency responses of most mics and musical instruments roll off at around 20 kHz. Thus, anything recorded above 20 kHz is probably junk anyway, just noise.
