Oscilloscopes are experiencing a bit of a comeback lately, thanks to some very clever pioneering by Jerobeam Fenderson, whose “Oscilloscope Music” art form relies on the dual inputs on vintage analog models. If you haven’t seen his work, search the Web for his impressive YouTube examples.
While Fenderson’s visual compositions require a deep understanding of audio in relationship to oscilloscopes, knowing the basics of waveform visualization is an extremely handy skill to have. My favorite free oscilloscope is included in the MeldaProduction MFreeFXBundle. It’s cross-platform and is a great way to get a closer look at the audio output of both hardware synths and DAW tracks.
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Many producers already know what clipping looks and sounds like, where the tops of the waveforms are sliced off, adding distortion. Viewing a clipped sine wave and recognizing that it sounds like a square wave because it looks like a square wave can be an enlightening experience (see Figure 1).
Additionally, it’s helpful to understand the appearance of different frequency ranges. For example, Figure 2 represents a single cycle of a sine wave at the fundamental frequency, while Figure 3 is just over 3 octaves higher, at the 11th harmonic, but with much lower volume. Though it’s obvious that the harmonic frequency is higher just by looking at the waveform, when you blend the two frequencies together in an additive manner, you’ll see a bit of sinusoidal “fringe” on the fundamental sine wave, displaying the additional frequency (Figure 4). Taken a step further, adding a touch of noise to the fundamental sine wave makes that “fringe” look more chaotic than the consistency of a sine-based harmonic (Figure 5).
To get the hang of these basics, try zooming in on a few favorite kick drums in your DAW of choice. Looking at the kick from the Linn Drum, it is instantly apparent which elements are the low and high frequencies that give the Linn its distinctive character (Figure 6).
What’s more, you can clearly see the higher frequencies at the beginning of the waveform, indicating its attack components. Finally, I’ll leave you with a tidbit that author and mastering engineer Steve Turnidge dropped on me a decade ago, and it still blows my mind when I stop to ponder it: If you rotate your waveform view 90 degrees so that it’s vertical, you’ll see a visual graph of the motion of your speaker as the waveform plays (Figure 7).
Next month, we’ll investigate a few useful tricks that you can apply by playing with the phase of a waveform.