What Are Sample Rate and Bit Depth? Why They Matter for Audio Systems
Recording in a digital system requires knowing about Sample Rate and Bit Depth. Let's understand what these two values are and why they matter.
When recording through digital audio equipment, the person recording needs to know a great deal about the resolution values of a digital audio signal, such as Bit Depth and Sample Rate. Many of you are well familiar with numbers like 44.1kHz, 96kHz, or 16 Bits, but for those who have only just begun learning to record, you may not yet understand what Sample Rate and Bit Depth actually are. Today we'll explain so there are no more doubts.
What Is Sample Rate?
Sample Rate is the number of samples of an Analog audio signal — converted into a Digital audio signal — taken within 1 second, measured in Hertz (Hz). For example, a Sample Rate of 44 kHz means that within 1 second, up to 44,000 samples of the audio signal are taken. Today, Sample Rates we can find range from 44.1 kHz up to 192 kHz, which means the higher these numbers, the more detailed the recording, making our audio signal more realistic and closer to the original sound.
What Is Bit Depth?
Bit Depth is the number of levels of difference in the audio signal within each Sample when an Analog audio signal is converted into a Digital audio signal. Bit Depth affects the tone of the work. Today, the lowest Bit Depth in use is 16 Bits, and the higher the Bit Depth, the more finely you can divide the number of difference levels in the audio signal — meaning you can capture audio data with more levels of signal difference.
Is More Always Better?
We might conclude that the higher the Sample Rate and Bit Depth, the more detailed and realistic the audio data we get. But there are some cases where you can't use a high Sample Rate and Bit Depth — for example, when the venue has noise present. Setting a high Sample Rate and Bit Depth would mean we also record that noise, which becomes a problem for mixing the audio or forces us to re-record.
And the higher the Sample Rate and Bit Depth, the more storage space we need for the audio files. If there aren't many files, this may not be much of a problem, but if we have a large number of files, our Hard Disk can fill up easily.
If we were to recommend what Sample Rate and Bit Depth to use, we'd say it depends on the destination medium. For example, for film audio work, a resolution of 48kHz / 16 Bits is mostly used, which is the audio standard for VDO files, while we might use higher resolution in the case of HD DVD or Blu-ray discs.