Saloon keepers loved the advent of digital audio because debating whether digital or analog is better is thirsty work. The debate rages on, but instead of clarity emerging as the years go by, we instead have more confusion. And you can blame it on the marketing department.
This issue came to the fore recently when “First Take” (FT) engaged “Final Mix” in a spirited discussion about digital microphones. FT asserted that a digital microphone was merely a regular old analog microphone with an onboard analog-to-digital converter, making the term digital microphone nothing more than one more example of marketingspeak. Instead, a true digital microphone, were such a thing possible, would perform a direct digital conversion, rather than using a traditional diaphragm arrangement. Otherwise, the term is meaningless.
“Final Mix” countered that sound was an analog phenomenon, meaning that the first stage of digitizing would have to be some kind of analog sensor, the output of which would then be sent to a converter. This approach seems to qualify as a “digital microphone” in the minds of the Audio Engineering Society (AES), which has a standard describing these mics, and manufacturers like National Semiconductor, which makes chips for them.
The debate romped on, but the underlying point was the lack of clarity in defining what constituted a “digital” version of a device that received analog input. Apparently, some see the microphone's digital output as defining it as “digital.”
Now “Final Mix”'s pea brain was in gear. What about digital loudspeakers? What are they? That turned out to be a bit trickier. In the majority of cases, the term is applied to a system that keeps the signal in the digital domain as long as possible, though eventually converting it to analog at the power amplifier stage. However, there have been a few systems that never convert the signal to analog, producing a digital signal that is “converted” to analog in the ear.
But this definition has been a topic of debate for years. In 1998 Stereophile magazine had an article exploring the definition of digital loudspeakers, while a paper presented at the 110th AES convention in 2001 defined a digital loudspeaker lacking any kind of DAC.
Is the case any clearer with digital amplifiers? Not really. The output of these devices, technically referred to as “Class D,” is a pulse-width modulation (PWM) waveform, which is lowpass filtered before being fed to a loudspeaker. Sounds pretty digital, doesn't it? But a 2001 article in Electronic Design News firmly asserted that the signal, PWM or not, is decidedly analog.
Are we confused yet?
Now let's flip things around and take a look at analog synthesis. Not the kind you get from an analog synthesizer, mind you, but the kind you find in various “virtual instruments” — whatever those are. I've seen “analog modeling” synthesis and just plain old “analog” synthesis in these products. Are these synthesizers using analog software or something? As near as I can tell, these terms refer to a voice structure employing simple waveforms (sine, sawtooth, square or pulse, triangle, noise), feeding a filter and a gain stage, with envelopes to control filter and gain behavior. Oddly, I somehow had come under the impression that constituted subtractive synthesis.
Come to think of it, those waveforms (and more) were used in Music I through Music V, the software-synthesis languages developed by Max Mathews and friends in the 1950s and '60s. Bear in mind that Bob Moog didn't show his first modular analog synthesizer until the 1964 AES convention. Maybe he should have claimed his instruments modeled digital synthesis.
Good grief! Our industry is smearing the distinction between the terms analog and digital so badly that they are rendered nearly useless. But “Final Mix” has an idea: pay no attention to any use of the words analog and digital in product descriptions. Instead, ask questions to determine how the technology actually works. Better yet, ask people at the product's manufacturer to define the use of their chosen term. It's really fun to watch them squirm as they are forced to admit that they have no idea what their terms mean.