In my opinion you have to look at the recording technology, the processing technology *AND* the instrument innovations that occured in that period. Guitar amplifiers went from low gain to extremely high gain, synthesizers debuted as analog monophonic bleep machines and matured into digital wonder boxes with thousands of amazing sounds available with over a hundred voices of polyphony (and then used digital technology to start emulating vintage analog sounds in the mid-90's), sampling started out as expensive and dull, 8 bit sounds and matured into a scratch-and-sniff, essential element of music production. (You wouldn't have modern rap music if sampling was as expensive as it originally was.) And with the creation of these new instruments came new music styles. Can anyone imagine new wave without sweeping analog synths? Or rap without an
Roland TR808 drum machine? Or techno without
a TB303? Or late 80's pop without cheesy Korg M1 sounds?
Here are some of the defining moments in my opinion:
60's: Beach Boys "Pet Sounds" was the inspiration for The Beatles to really step things up production wise (as well as the deep bass sound found on Motown records) that led to "Sgt. Peppers." At this time there was a huge push from 4 track recorders to larger track counts on analog tape machines, however, with the addition of more tracks meant that each individual track was smaller in width and therefore "thinner" sounding (according to George Martin). A lot of tube gear was being slowly replaced by solid state devices such as FET and VCA based compressors. Reverb at this time was either natural room ambiance, large unweildy plate reverb, or cheap spring reverb. Keyboards at this time were mostly electro-mechanical like the Farfisa organs,
the Hammond B3, although the first Moog modular synthesizers debuted in the late 60's (however, don't forget the Theremin which started popping up on Beach Boy's tracks early in the 60's).
70's: Jimmy Page is often underrated for his influence on the sound of Led Zeppelin's albums. Tom Scholz's work on the Boston albums really set the pace for the 80's. This era was marked by an ever-increasing track count, more "effect" devices such as the Echoplex, some of the first digital devices like the early Eventide harmonizers, as well as the addition of parametric equalization (courtesy of George Massenburg's 1972 AES paper). Also, the 1970's mark the entry of the first AFFORDABLE electronic synthesizers, starting in 1971 with
the ARP 2600,
Moog Minimoog, ARP Odyssey. Also, don't discount the dub reggae influence on later music production.
80's: The 80's were a decade of "larger than life" sounds made possible by increases in digital and analog technology that introduced devices like the digital sampler (such as the Fairlight CMI, Emu Emulator I and II) which enabled drum parts to be triggered. Affordable digital reverbs by companies such as Lexicon and Yamaha accounted for the sound of this era--which was put reverb on EVERYTHING. Chorus was another popular effect, almost single-handedly defining the "New Wave" sound (ex. The Police, Corey Hart, others). The entire credo was "bigger is better." Probably the most influential recording was Phil Collins "In The Air Tonight" because it had *THE* gated-reverb drum sound that defined the decade. Probably the most defining engineer of the 80's was Mutt Lange, who's work with The Cars, Def Leppard and AC/DC best exemplify the "80's sound."
90's: The 90's was a decade of upstarts. There wasn't a lot of NEW technology, but what had been available in the past became cheaper. Digital recording starts out on wobbly legs early on and matures by the end of the decade. The early 90's simplified the sound of the 80's. Nirvana's "Nevermind", typically considered the 'biggest' album of the decade, also typifies this sound--clear, big (but not too big), and slick sounding. As the 90's went on acts like Nine Inch Nails embraced digital platforms like ProTools (using it more as an instrument than a recorder to "mangle" sound) to create new textures. In many ways the 90's are a reaction against 80's production values--creating a DIY, dirty and unusual sound--especially for percussion, which was made smaller sounding. Another interesting note is that the 90's moved away from the "snare dominated" sound of the 80's and began focusing more on the kick drum as the primary percussive element in rock music. On another note, Ricky Martin's "Living La Vida Loca" was the FIRST #1 song that was recorded, mixed and mastered completely digital--thus validating the digital medium as a recording and production platform. While not many new instruments were created during this time, the step toward digital emulation of other instruments (first keyboards and synthesizers, later on emulation of guitar amps, vintage effects, etc...) was in vogue. Also, the late 90's saw the creation of a number of software standards such as Steinberg's VST platform which accelerated the development of software plugins.
00's: Now that digital recording has come into its prime and every effect under the sun is available to almost anyone we run into the conundrum that there are a LOT of engineers out there working with tools they may only partially understand. Because recording technology is so commonplace the musicians have a greater understanding (sometimes I'd say half-understanding) of production. This is the age of ABUSING the recording tools, not *using* them. The sound of "now" is an age of excess--radical compression, radical peak limiting, radical EQ'ing, radical sound replacement. In many ways this is a tasteless decade of childish, unwise musical excess. As much as we may wiggle our fingers in disapproval and laugh at the gated reverb of an 80's hair metal band the thought that in 10 years the production techniques of now will be as equally dated. Hopefully the mistake isn't made that the sounds of "now" were a result of inferior digital software and hardware, but the result of overcompression, too much distortion, and judgement thrown off by too-few record sales in what may be the biggest music recession of the last 100 years.