More clarity and explanation for audio effects (#8304)

* Update tutorials/audio/audio_effects.rst

---------

Co-authored-by: A Thousand Ships <[email protected]>
Co-authored-by: Max Hilbrunner <[email protected]>
Co-authored-by: Matthew <[email protected]>

Author: 4 people

tutorials/audio/audio_effects.rst

@@ -16,9 +16,9 @@ description of the available effects:
 Amplify
 ~~~~~~~
 
-Amplify changes the amplitude of the signal. Some care needs to be taken.
-Setting the level too high can make the sound clip, which is usually
-undesirable.
+Amplify changes the volume of the signal. Some care needs to be taken, though:
+setting the level too high can make the sound digitally clip, which can produce
+unpleasant crackles and pops.
 
 BandLimit and BandPass
 ~~~~~~~~~~~~~~~~~~~~~~
@@ -39,30 +39,33 @@ or to transmit audio over the network in real-time.
 Chorus
 ~~~~~~
 
-The Chorus effect duplicates the incoming audio, delays the duplicate slightly
-and uses an LFO to continuously modulate the pitch of the duplicated signal
-before mixing the duplicated signal(s) and the original together again. This
-creates a shimmering effect and adds stereo width to the sound.
+As the name of the effect implies, the Chorus effect makes a single audio sample
+sound like an entire chorus. It does this by duplicating a signal and very
+slightly altering the timing and pitch of each duplicate, and varying that
+over time via an LFO (low frequency oscillator). The duplicate(s) are then
+mixed back together with the original signal, producing a lush, wide, and
+large sound. Although chorus is traditionally used for voices, it can be
+desirable with almost any type of sound.
 
 Compressor
 ~~~~~~~~~~
 
-A dynamic range compressor automatically attenuates the level of the incoming
+A dynamic range compressor automatically attenuates (ducks) the level of the incoming
 signal when its amplitude exceeds a certain threshold. The level of attenuation
 applied is proportional to how far the incoming audio exceeds the threshold.
 The compressor's Ratio parameter controls the degree of attenuation.
 One of the main uses of a compressor is to reduce the dynamic range of signals
 with very loud and quiet parts. Reducing the dynamic range of a signal
-can make it easier to mix.
+can make it fit more comfortably in a mix.
 
 The compressor has many uses. For example:
 
-- It can be used in the Master bus to compress the whole output.
+- It can be used in the Master bus to compress the whole output prior to being hit by a limiter, making the effect of the limiter much more subtle.
 - It can be used in voice channels to ensure they sound as even as possible.
-- It can be *sidechained*. This means it can reduce the sound level
+- It can be *sidechained* by another sound source. This means it can reduce the sound level
   of one signal using the level of another audio bus for threshold detection.
   This technique is very common in video game mixing to "duck" the level of
-  music or sound effects when voices need to be heard.
+  music or sound effects when in-game or multiplayer voices need to be fully audible.
 - It can accentuate transients by using a slower attack.
   This can make sound effects more punchy.
 
@@ -71,22 +74,30 @@ The compressor has many uses. For example:
     If your goal is to prevent a signal from exceeding a given amplitude
     altogether, rather than to reduce the dynamic range of the signal,
     a :ref:`limiter <doc_audio_buses_limiter>` is likely a better choice
-    than a compressor.
-
+    than a compressor for this purpose. However, applying compression before
+    a limiter is still good practice.
 
 Delay
 ~~~~~
 
-Adds an "echo" effect with a feedback loop. It can be used together
-with *Reverb* to simulate wide rooms, canyons, etc. where sound bounces
-are far apart.
+Digital delay essentially duplicates a signal and repeats it at a specified
+speed with a volume level that decays for each repeat. Delay is great for
+simulating the acoustic space of a canyon or large room, where sound bounces
+have a lot of *delay* between their repeats. This is in contrast to reverb,
+which has a more natural and blurred sound to it. Using this in conjunction
+with reverb can create very natural sounding environments!
 
 Distortion
 ~~~~~~~~~~
 
-Makes the sound distorted. Godot offers several types of distortion: *overdrive*,
-*tan* and *bit crushing*. Distortion can be used to simulate sound coming through
-a low-quality speaker or device.
+Makes the sound distorted. Godot offers several types of distortion:
+
+- *Overdrive* sounds like a guitar distortion pedal or megaphone. Sounds distorted with this sound like they're coming through
+  a low-quality speaker or device.
+- *Tan* sounds like another interesting flavor of overdrive.
+- *Bit crushing* clamps the amplitude of the signal, making it sound flat and crunchy.
+
+All three types of distortion can add higher frequency sounds to an original sound, making it stand out better in a mix.
 
 EQ
 ~~
@@ -97,10 +108,15 @@ scripts to create an equalizer with a custom number of bands.
 EQ6, EQ10, EQ21
 ~~~~~~~~~~~~~~~
 
-Godot provides three equalizers with different numbers of bands. An equalizer on
-the Master bus can be useful to cut frequencies that the device's speakers can't
-reproduce well (e.g. a mobile phone's speakers won't reproduce bass content
-well). The equalizer effect can be disabled when headphones are plugged in.
+Godot provides three equalizers with different numbers of bands, which
+are represented in the title (6, 10, and 21 bands, respectively).
+An equalizer on the Master bus can be useful for cutting low and high
+frequencies that the device's speakers can't reproduce well.
+For example, phone or tablet speakers usually don't reproduce
+low frequency sounds well, and could make a limiter or compressor
+attenuate sounds that aren't even audible to the user anyway.
+
+Note: The equalizer effect can be disabled when headphones are plugged in, giving the user the best of both worlds.
 
 Filter
 ~~~~~~
@@ -125,8 +141,8 @@ Limiter
 ~~~~~~~
 
 A limiter is similar to a compressor, but it's less flexible and designed to
-prevent a signal's amplitude exceeding a given dB threshold. Adding a limiter to
-the Master bus is a safeguard against clipping.
+prevent a signal's amplitude exceeding a given dB threshold. Adding a limiter to the final point of
+the Master bus is good practice, as it offers an easy safeguard against clipping.
 
 LowPassFilter
 ~~~~~~~~~~~~~
@@ -151,21 +167,25 @@ Panner
 ~~~~~~
 
 The Panner allows the stereo balance of a signal to be adjusted between
-the left and right channels (wear headphones to audition this effect).
+the left and right channels. Headphones are recommended when configuring in this effect.
 
 Phaser
 ~~~~~~
 
-It probably does not make much sense to explain that this effect is formed by
-two signals being dephased and cancelling each other out. You can make a Darth
-Vader voice with it, or jet-like sounds.
+This effect is formed by de-phasing two duplicates of the same sound so
+they cancel each other out in an interesting way. Phaser produces a
+pleasant whooshing sound that moves back and forth through the audio
+spectrum, and can be a great way to create sci-fi effects or Darth
+Vader-like voices.
 
 PitchShift
 ~~~~~~~~~~
 
 This effect allows the adjustment of the signal's pitch independently of its
 speed. All frequencies can be increased/decreased with minimal effect on
 transients. PitchShift can be useful to create unusually high or deep voices.
+Do note that altering pitch can sound unnatural when pushed outside of a
+narrow window.
 
 Record
 ~~~~~~
@@ -185,10 +205,12 @@ SpectrumAnalyzer
 ~~~~~~~~~~~~~~~~
 
 This effect doesn't alter audio, instead, you add this effect to buses you want
-a spectrum analysis of. This would typically be used for audio visualization. A
-demo project using this can be found `here <https://github.com/godotengine/godot-demo-projects/tree/master/audio/spectrum>`__.
+a spectrum analysis of. This would typically be used for audio visualization.
+Visualizing voices can be a great way to draw attention to them without just
+increasing their volume.
+A demo project using this can be found `here <https://github.com/godotengine/godot-demo-projects/tree/master/audio/spectrum>`__.
 
 StereoEnhance
 ~~~~~~~~~~~~~
 
-This effect uses a few algorithms to enhance a signal's stereo spectrum.
+This effect uses a few algorithms to enhance a signal's stereo width.