A lot of people have trouble discerning the difference between sample rate and bit rate when discussing digital audio so I thought I would give a simplified explanation to try and help out.

Sample rate refers to the frequency at which the sound source in a recording situation is sampled.

You’ve probably heard that CD quality recordings are at 44.1khz and DVD products can go from 96khz to 192khz depending on whether it’s a DVD-A, movie soundtrack, etc. Digital recording (which can also be called Digital Sampling) is a method whereby the recording device “samples” the sound source at timed intervals. Obviously the faster we sample the sound the more accurate the recording we’ll achieve. Picture our device sampling our sound source at 44,100 times a second…this gives us “CD Quality”(44.1khz). More than double that speed to 96,000 times a second and you’ve increased the precision, hence the quality of the recording. In easy to understand terms the higher the sample rate the higher the quality of the recording, but there is a trade-off… the higher we go in sample rate the larger the audio file becomes. CD Quality (44.1khz) was based on fitting a full album on a CD at the highest quality possible. Seeing as how the DVD has a larger storage capacity we can easily work with higher sample rates on that format.

There is an argument that at a certain point in sample rate we won’t be able to hear a difference any more but we’ll leave that discussion for another time.

Bit rate refers to how much information is sampled each time the recording device captures the sound source. We know that the faster we sample the better the quality of our recording, but if you are working a low bit rate you might not get the same result as using a larger bit rate at a lower sample rate. Some common bit rates are 8-bit (your Windows sounds are a good example of this), 16-bit (CD Quality), and 24-bit (DVD). Differences in bit rate affect the dynamic range of a recording (the difference between the quietest and loudest sounds). There is a 20-bit process that has been used but the general use audio rates are 8, 16, and 24.

For a point of reference I record my audio at 96khz and 24-bit. Everyone has their preference, you’ll just have to experiment to find what works for you. Just remember the higher the quality the greater the file size and the higher the load on your computer. You’ll also need a soundcard that can achieve the quality rate you wish to use.

There’s a ton of material on this subject so this is definitely an abridged version, if you’re interested in more information it’s out there…Google is your friend as they say.

-Bill