Ideally the best sample rate and audio bit depth for recording is as high as possible as your recording software and hardware can handle. Below are common sample rates used in recording:
a.) 44.1 KHz
b.) 48 KHz
c.) 96 KHz
d.) 192 KHz
And below are the common audio bit depths:
c.) 32-bit float
But for most home studio applications, selecting 32-bit float and 192 KHz is not practical. It is because when you are tracking at this bit depth and sample rate; even a 2-second audio sine wave (the simplest form of audio wave) is already 1.46MB in file size. The real audio you are recording; that is the sound of your voice, guitars, etc are complex waveforms that demand VERY large file sizes when recorded at this given sample rate and bit depth.
Advantages of high audio sample rate and bit depth
But what are the advantages of recording at the highest sample rate and bit depth possible? One obvious advantage is that your digital recording captures almost the entire analog sound perfectly. Remember in the analog audio to digital conversion; the music you hear and all the sound that surrounds you are “analog” in nature. When you like to record it to your computer hard drive, it will be digitally converted. A higher bit depth and sample rate during recording will provide a more accurate representation of the analog signal in digital domain. The only downside is that the resulting file size will be very large typically if you are planning to create lots of recording and do a lot of projects. You will be running out of hard drive space very early.
Going at the low end, selecting 8-bit depth and 44.1 KHz (or even lower) does not do any good. Why? It is because the digital representation of your analog recorded sound is far from being accurate. In other words, the recording results have low fidelity.
Best practices in audio bit depth and sample rate
Professional music production has its best practices in sample rate and bit depth. These are the following:
a.) The most common bit depth and sample rate used in commercial audio and broadcasting is 16-bit/44.1Khz (this is the sample rate of CD audio, commercial MP3, etc that you found in recording stores, streamed in Internet radio, everywhere). Most MP3 and audio players are configured to play at this sample rate and bit depth.