We have effects plugins of almost limitless possibility, rack mount effects units at nearly every price range, synthesizers with "built in" effects modules, effects controllers that track hand movements in the air or our finger on  an XY surface, and today's newest sequencers have effects whose parameters can be automated and modulated as the sequencer runs.  So much power!  Yet there is so little knowledge!  Knowledge of what effects are, how and when to use them, and how to create them. 

An effect is the modulation or modification of an audio signal to make it sound more interesting.  The use of effects, historically, has followed the development of audio recording devices form the beginning.  To really understand the terminology used in modern effects racks and plugins, you need to understand how these words came into being in the first place. 

Reverb Effects. 

Before the widespread proliferation of television sets in the 1950s, reverb effects were already in use in studios making records.  The early reverbs were based on microphone and transducer technology. Reverb was created naturally in good sounding rooms or "chambers" with highly reflective walls and movable baffles. Microphones were placed in the room at various location to pick up the ambient sound.  Most studios could not afford a room with enough size so plate and foil reverbs quickly came about. The Plate reverb was really a large steel plate, held up inside a frame so it could vibrate freely. The plates were anywhere between 6 and 18 feet tall and had to be isolated in a room of its own.  Imagine trying to do a home studio in those days!  Amplified soundwaves would make the plate radiate, like a large gong does, and microphones would pick up these vibrations and send them back to the control room as an audio signal.  So when you look at your digital FX box and see "plate reverb" and "chamber reverb" that's what these effects are tryng to emulate through digital mathematics.  Lets move on.
 The Spring reverb came about next and was quickly adopted by guitar amps.  Inside these units was a metal spring, like a Slinky,  that vibrated with the amplified audio.  You may have seen guitarists bang on their amps to get the spring to distort, and many radio shows used this effect to simulate thunder and lightning.

Delay effects 

Early delay effects were made based on tape recorder technology and were made on reel to reel tape recorders.  Due to the gap between the playback head and record head, it was easy to get echo by simply monitoring the signal from both heads at the same time.  Because you could slow down and speed up the reels (by hand, or later with VariSpeed), you could get echoes of various length. Later reel to reels let you add the playback signal back to the source signal, which created feedback (that would go wildly out of control if you added too much).  One innovation done on tape decks was called Flanging. 

While the reels were moving, the engineer would put his hand on the flange of the source reel to slow it down slightly and create the effect. When the slowed down source signal was added to the original signal at the playback head, the slight change in pitch could create the authentic flange effects  Now you know where the term came from on your stomp box.  Another effect that worked in a similar way was phase shifting.  Here the source signal was delayed  from the playback signal and added back in at an equal level with feedback.  The result was an audio signal that shimmered and swooshed as the two signals went in and out of phase.  

Chorusing was another effect the reel to reel did.  By increasing the drag on the flange, the source signal would slow down even more to where a solo vocalist sounded like a chorus group. Finally, one could record a slightly slowed track next to the source track.  This effect is called "doubling" and results in a thicker vocal.  You have probably heard this a few million times on records.  Probably the ultimate tape effects were Tape loops, and with these, special effects turned into a craft all it own.

After you talked through the microphone the sound would go in and out of 4 heads, with feedback on both machines.  After your recorded your material, you could "rock the reels" and get all kinds of flanging effects, double slapback effects, pitch warping effects, syncopated delays "multi tap" delays.

What, Effects without Plugins?

Interestingly, many of the above are all effects you can get in a modern digital audio sequencer without using any plugins at all. You simply copy tracks and offset the pitch and start time.  And guess what, it usually sounds better and more authentic if you craft an effect this way.  And if you really want to stand out from the crowd, go down to the local pawn shop and find an unloved reel to reel sitting there.

By now you should be marveling at how inventive human being have been to make their audio standout from the rest. Why?  Because new and unheard effects often translated into mega-hit records especially when paired with a well known artist and it is still going on.  In the 70s and through the 80s, effects technology took off on the low end with guitar pedals featuring distortion, wah-wah, chorusing,  flanging and phase shifting. Analog delays used tape inside a small box with several playback heads .  One of the classics here was the Roland Space Echo. The digital delay was first and was quckly followed by digital reverb which at the beginning was very expensive, and then finally multi-effects boxes that did everything.  Some landmarks in the development of effects were the Midiverb, the product that brought Alesis into the recording world.  The Midiverb was a flat square box that had several types of digital reverb for abound $500 bucks.  Yamaha came out with the SPX-90 which boasted 90 different FX programs that were user editable and recallable by midi program changes.   Effects units then proliferated till they were nearly everywhere and the prices on them have plummeted on all but the best quality effects units. 

The Plugin Revolution. 

It became evident after a while that what distinguished a quality effects unit from an inferior one was mostly due to the quality of the software algorithm, the code.  Because the code was developed on a computer, it was just a short step to use the computer's audio resources to play the effects.  The plugin, a small program containing an effect algorithm was born and by 1997, were making inroads in Logic and Cubase VST.    Early plugins sounded OK when they just sat there doing an effect, but if you changed a parameter, you'd often get (and still do get) a digital zipper-like noise.  Improvements of the last few years have made these dynamics smoother and more musical to the point where plugins can now be tweaked in real time on a computer, in way like the early engineer could rock the reels.

Just like our early ancestors came up with flanging and delays by abusing the motors on their reel to reel decks, we need to be just as extreme today to get new great sounding effects.  Rule number one.  There are no rules.  The coolest sounds come from a relentless drive to experiment.  Use any device in you studio to create your effects.  Go WILD.  That's how you come up with great stuff.