It is rather slippery trying to define what is or isn't on-topic on a mail list. On a mail list dedicated to analog synthesizers, sometimes I come across people who think anything that isn't digital is analog and therefore on-topic. Or, sometimes I'll hear 'it is all analog by the time it reaches our ears'
OK, first of all, acoustic is not analog. But, let's break this down, because it is interesting.
A Capella
Music made using only the human body, such as singing, is the only form that has no external mechanical requirements. I mean, besides a transmission medium like air.
Acoustic Mechanical Tools
This group makes up what we normally think of as musical instruments. Or, as some people like to say, 'real' musical instruments. This is any tool that is powered exclusively through the musician operating the instrument. So, all the instruments of the traditional orchestra, acoustic guitars, drums - all of these fall into this category. A human being on a bike can travel much faster and farther than one who is on foot, yet, the human is still the only source of power. Mechanical augmentation is certainly a powerful concept. Consider how the piano opens up sophisticated worlds of harmony and counterpoint to a single person. Look at how complicated a French Horn is. What marvelous product of technology. Have you ever inspected how a hammer strikes a string in a piano? Each of the 88 keys is a refined Rube Goldberg contraption. Totally unnatural.
Power-assisted Non-electric
This is a strange category of instruments that pre-date electricity, yet employ a source of power external to the person operating the instrument. The Hydraulus, invented by Archimedes used water power to supply the wind for something similar to pipe organ. Later, poor schmucks known as calcants were used as bellows operators for pipe organs while the organist played. Eventually, calcants were replaced by electric motors at the end of the 19th century, bringing pipe organs into the next category.
Electric Instruments
Take a guitar, add electricity and it is no longer a musical instrument. At least, that is what its detractors claimed at the time. Instruments that use electricity to amplify or shape the output belong in this category. This is where we derive the traditional rock band instrumentation, but the roots go back further. Have you ever been in the presence of a big band? They're fricking loud. Can you imagine singing in front of one, in a casual, off-hand manner like Bing Crosby without the assistance of a microphone and amplification? Couldn't have happened without electricity.
Electrical Instruments That Generate a Tone
I'm going to create a special category here for instruments like the Hammond B3. It is different from an electric guitar, in that the principle tone is generated internally. The guitarist sets the string in motion - it is primarily an acoustic event that is shaped and amplified electronically. The Hammond is more like a fly-by-wire system where the musician is completely divorced from the physical aspect of generating a tone.
Analog
With the Hammond, there was something physical inside generating the tone: the mechanical tonewheel. With the advent of analog synthesizers, the tone itself is no longer mechanical, but purely electric; generated by an oscillator. Nothing vibrated except electrons. Instruments in this category include the Theremin, Ondes Martenot, Buchla and Moog analog synths and more.
Digital Synthesis
Max Matthews, working at Bell Labs, researching means of producing better telephones came up with the idea of speeding up the process by modeling characteristics with a computer. We're talking 1950s computers. By attaching a rather expensive digital to analog convertor to an IBM 704, Max ushered in a world where audio could be represented as ones and zeros, and, in the process, finally offered a means where someone could conceivably control every minute tonal detail over time with software. Audio became 100% virtual.
Software-Assisted Composition
A complex piece of music can be assembled by one person via overdubs, but this is not a real-time process. There is only so much a single musician can do in real-time without intelligent assistance. This is one reason why many musicians choose to play together. Unfortunately, this sometimes becomes rather messy. Digital Arrangers, Karma, Tenori on, and various types of algorithmic composition software allow a musician to invoke (for lack of a better term) macros that respond to real-time input, producing a layered, more complex composition than could be performed without augmentation.
As we've seen so far, each step in this progression has increased the control or expressive capabilities of the musician, at the expense of increasing the distance between the musician and musical event.
