We explain dither in plain English.
On first glance, dither can seem complex and confusing but once you understand it, dither will forever be your friend, promise. The secret is knowing what it is and when to use it.
dith•er (ˈdɪð ər)
1. a trembling; vibration.
You know when you tap an analogue meter with your finger to help it perform better? This is the early meaning of dither and the concept is very simple: basically, nervous energy helps analogue systems perform better. In the case of digital audio, adding low-level noise will actually improve the overall feeling of your track. It may sound counterintuitive, but adding a special type of noise will help randomize errors and mask distortion in your tracks.
When you record tracks you should record at the highest bit-depth / sample rate possible, I recommend 24bit/48kHz (more on this in the future). And although your mix will sound its best in 32 or 24-bit, your song will inevitably need to be reduced in bit-depth so that you can share it with the world. Bit-depth reduction is a process in which the least significant bits of your music get removed to save data space (ex. when you go from 32-bit to 24-bit or to 16-bit). Let’s do an experiment and see what’s happening.
Here’s a sine tone I made in Ableton, note the nice natural curves and how that translates in the sound you are hearing.
Here’s the visual wave form:
Lets make an extreme example and reduce the bit depth to 1-bit and illustrate the point. Then we’ll take a look/listen to what happens when you bit reduce:
Visual waveform of the bit reduced version:
Our nice curves are now square waves, this is literally distortion. The good news is no one is going from 24-bits to 1-bit, but the principal is the same: reducing bits cuts sound arbitrarily. This is where our nervous friend dither comes in, redistributing the errors made in the bit-depth reduction in a more natural, random arrangement.
Take this photo of a bearded man as an analogy. Image and sound are both just signals, after all. The photo on the left is the original, the middle is the downsampled version and on the right is the dithered version. Though it’s not as clear as the original, the dithered version is perceived by the brain as closer to the original than the bit reduced version.
So, when do you dither?
If you absolutely have to lower the bit-depth in a session while working on a project you should apply dither. However, it’s best practice to only dither once, it should be the last step before duplication or net distribution. This means that if you are preparing your tracks for LANDR, or a mastering engineer, you should try to avoid reducing bit-depth. LANDR will dither and reduce bit-depth for you. Most digital audio workstations will have the option to turn dither off when exporting.
Here’s the export window from Ableton. Note that I am exporting in the same bit-depth/sample rate I recorded in as to not down sample or mess with the bit-depth.
Title image by Moonbahn
Check back often for more production tips and tricks and remember: only dither once!