In the world of audio technology, we often use tools such as compressors and limiters to smooth out the peaks of a signal, which raises the overall volume of that signal. However, conventional compression is not the only way to thicken up a sound. A small amount of distortion, often referred to as saturation, can add character and density.
A compressor turns down the overall signal amplitude of a snare drum, for example, when it exceeds a certain level. Similarly, distortion sort of “chops” the wave form. Saturation is merely a more subtle form of Distortion. The differences between various types of distortion and saturation depend on how the signal is clipped. A digital clip, also known as a hard clip, simply removes the top of the wave form (see image below).
An analog clip is a bit more musical sounding than a hard clip, which often sounds objectively bad (a term I rarely get to use in the world of music). When a tube amp, for example, is driven hard enough to distort, it doesn’t simply slice the signal. Instead, it accentuates musically pleasing harmonics, also known as “even and odd order harmonics.”
Naturally, different types of distortion emphasize different harmonics. However, in all cases of musical distortion, the resulting wave form is smoother and more pleasant sounding than digital distortion. The result is fuller, denser sound. It’s a beautiful thing. You have achieved a bit of compression without even using a compressor, plus you have created a more interesting and complex sound.
Saturation sometimes comes with unwanted side effects, though. If you overuse it, your mix will quickly begin to sound messy and lack clarity—especially if the saturation wasn’t necessary in the first place. Also, saturation on instruments but not vocals sometimes leaves the timbre of the singer’s voice sounding a little plain (especially in more stripped down productions).
When considering whether to use saturation, make sure you have a reason and a plan. If you have a chorus with 12 guitars, a full drum kit, backing vocals, strings, horns, and synth pads, perhaps the overall sound of that chorus is complex and interesting enough without saturation. That said, if you have a beat with sparse instrumentation, maybe a bit of saturation of the 808s could make them sound more unique, helping them cut through the mix a little better.
Peter is a recording and mixing engineer, and specializes in music production for artists as well as films. He also sings and plays guitar in the Indie Rock band Calm and Crisis. Peter’s most recent work includes his band’s debut LP In A Real Good Place, a single with the NYC based artist Roarke, and a collaborative Rock/Hip Hop song with DC rapper SpennyAlmost which is set to be placed in the Starz film, Flock of Dudes. Peter is a BA/MA student in the Audio Technology Program at AU.
If you are interested in a career as a mixing or sound engineer, learn more about the audio technology degree programs at American University.