#5thAvenueBlogs | Digital Audio Basics [Blog]
Toronto, ON – Where better to start with digital audio than the fundamentals? In this blog I explain what both sample rate and bit depth are and why they are important to achieving high quality sounds in your recordings and productions.
It’s interesting to think of the example of simple animation by way of a flipbook. You draw a stick man on one page, and gradually move it across the pad, one small movement on one page at a time. If you have a thicker flipbook with lots of pages, you can have very smooth movements. If you want to add definition to your drawings by using different shades of your pencil, you’d have yourself a beautiful simple animation.
Digital audio is similar; sample rate is the number of pages in your flipbook, and bit depth is the number of shades your pencil can produce.
By definition, a sample rate is the total number of samples per second of the audio file. Standard CD quality is 44.1K, which means 44,100 total samples per second. It seems like a lot, and it is, especially if you consider that films have a normal frame rate of 24 frames per second. Yes, the ears are much more astute and sensitive than the eyes. Quite simply, the higher the sample rate, the higher the quality of the audio. Nowadays, studios are recording in 88.2K or 96K and this is done mainly for two reasons. First, it’s a more accurate recording and mix judgments can be more precise. Second, it’s a better starting point for file conversions. One thing to note about sample rates – you cannot take a file with a lower sample rate and convert it to a higher sample rate, however you can take a file with a higher sample rate and make a copy with a lower rate. That’s why it is important to start the process with the higher sample rate.
Next is bit depth, which is defined as the resolution of each sample. For the purpose of this blog, I will describe it as volume control. Going back to the original example of the flipbook animation, I mentioned the different shades of your pencil. From dark to light shades, the more that you can define between both extremes gives you more control over your drawing. Bit depth is the same except it deals with the amount of decibels that can be recorded in each sample of your audio. CD quality is 16-bit, which gives a total dynamic range of 96 dB. 24-bit recordings can achieve a range of 144 dB. That’s a huge difference and is audible to most critical listeners.
Something that is important for beat makers to consider when choosing samples. If you’re using an .mp3 to rip a sample, odds are it’s in 44.1/16 as most .mp3′s originate from CD’s. If you’re using a sample pack for your kicks and snares, find out what the sample rates are of those files. If you’re session is running a different sample rate than your files, you might experience timing issues known as ‘jitter’.
For vocalists, try to record in the highest rate and depth possible. Remember, you can always go down, but never up.