Resolve requests

- typos and syntaxes
- add explanation for destroying

docs/source/tutorial/effect.rst

@@ -8,7 +8,7 @@ This section will focus on how to add effects to the audio.
 There are two set of audio effects supported by palace: :py:class:`ReverbEffect`
 and :py:class:`ChorusEffect`.
 
-Reverb effect
+Reverb Effect
 -------------
 
 Reverb happens when a sound is reflected and then decay as the sound is absorbed
@@ -17,6 +17,54 @@ by the objects in the medium.  :py:class:`ReverbEffect` facilitates such effect.
 Creating a reverb effect can be as simple as:
 
 .. code-block:: python
-   effect = ReverbEffect()
-   source.sends[0].effect = effect
+
+   source.sends[0].effect = ReverbEffect()
+
+:py:attr:`Source.sends` is a collection of send path signals, each of which
+contains `effects` and `filter` that describes it.  Here we are only concerned
+about the former.
+
+The above code would yield a *generic* reverb effect by default.
+There are several other presets that you can use, which are listed
+by :py:data:`reverb_preset_names`.  To use these preset, you can simply provide
+the preset effect name as the first parameter for the constructor.  For example,
+to use `PIPE_LARGE` preset effect, you can initialize the effect like below:
+
+.. code-block:: python
+
+   effect = ReverbEffect('PIPE_LARGE')
+
+These effects can be modified via their attributes.
+
+.. code-block:: python
+
+   effect.gain = 0.4
+   effect.diffusion = 0.65
+   late_reverb_pan = 0.2, 0.1, 0.3
+
+The list of these attributes and their constraints can be found
+in the documentation of :py:class:`ReverbEffect`.
+
+Chorus Effect
+-------------
+
+:py:class:`ChorusEffect` does not have preset effects like
+:py:class:`ReverbEffect`, so you would have to initialize the effect attributes
+on creation.
+
+There are five parameters to initialize the effect, respectively: waveform,
+phase, depth, feedback, and delay.
+
+.. code-block:: python
+
+   source.sends[0].effect = ChorusEffect('sine', 20, 0.4, 0.5, 0.008)
+
+For the constraints of these parameters, please refer to the documentation.
+
+Destroy the effects
+-------------------
+
+Like other objects in palace, effects must be destroyed after it has its jobs
+done with `__exit__()`.  If you use `with` syntax (you should) as mentioned in
+previous tutorials, the method will be called when you exit the `with` block.