In 1983, the music world was shaken by the introduction of a new instrument, the Yamaha DX7. The DX7 was the first digital synthesizer – the first instrument to generate sounds from data – to overcome the challenges of its digital predecessors and experience commercial success. It was both portable and affordable, and it had new features its analog predecessors lacked such as the ability to save sounds in digital memory for later. The DX7 went on to shape the sound of much of the music in the 80s and 90s, and it is credited with bringing about the decline of analog synths.
Analog synthesizers don’t seem to be gone for good, though. Many companies are beginning to make analog synths again. For example, Korg recently reissued its classic MS20 and Dave Smith Instruments recently announced the all-new Prophet 6. Given the advantages of digital instruments, why are companies bothering? Why is there a demand for new analog instruments? The answer lies in the way they generate sound.
Sound is the variation of pressure in the air as perceived by the eardrum. When sound is recorded with an analog system, it is converted into an electrical signal where the height of the sound wave is proportional to signal strength. A stronger signal will model a taller wave. When sound is recorded on a digital system, wave height is recorded as a number. This means analog systems generate and capture sound continuously while digital systems generate and capture sounds in steps. The tiny loss of detail that comes with capturing sound in steps is called “loss”. So digital systems have loss while analog systems are “lossless”. This is also the reason some people prefer analog sounds to digital sounds – they feel that analog instruments sound more smooth and “liquid” because they create sound continuously instead of in steps.
Two important differences and digital signal are bandwidth, defined as the range of frequencies they can capture, and signal-to-noise or S/N ratio, the ratio of the amount of desired sound to unwanted background noise. Analog system bandwidth is constrained by the quality of the circuits used, and digital system bandwidth is constrained by the sampling rate, the speed at which the system measures a sound wave. In recent years, many digital systems have achieved sampling rates high enough to functionally match the quality of analog sounds, causing many to call into question whether it’s even possible to hear a difference between an analog signal and a digital signal of sufficient quality. Will digital ever really kill analog? Only time will tell. I maintain that both are very useful and relevant types of instruments for music production, depending on the type of sound desired. I’ve attached a video with analog and digital synthesizers from the same company played together for comparison. See which one you like more!
– Erik Johnson
