Merge pull request #1390 from tildearrow/doc-general

Minor updates and cleanup of docs.

doc/2-interface/menu-bar.md

@@ -122,6 +122,7 @@ the following settings are available:
   - I suggest you use the same rate as the song's.
   - apparently ZSM doesn't support changing the rate mid-song.
 - **loop**: enables loop. if disabled, the song won't loop.
+- **optimize size**: removes unnecessary commands to reduce size.
 
 click on **Begin Export** to... you know.
 

doc/2-interface/settings.md

@@ -49,7 +49,6 @@ settings are saved when clicking the **OK** button at the bottom of the dialog.
 - **When creating new song**:
   - **Display system preset selector**
   - **Start with initial system**
-- **Restart song when changing chip properties**
 
 ### Start-up
 

doc/4-instrument/README.md

@@ -1,6 +1,16 @@
 # instrument editor
 
-every instrument can be renamed and have its type changed.
+the instrument editor always starts with this section:
+
+![top of instrument editor](instrument-editor-top.png)
+
+- top-left numeric dropdown: instrument selector.
+- folder icon: open an instrument file.
+- save icon: save current instrument as a file.
+  - right-clicking gives the option to save a .dmp format DefleMask preset.
+- **Name**: instrument name.
+- **Type**: the system for which the instrument is intended.
+  - if changed, all applicable settings and macros will remain as they are. numbers will not be adjusted.
 
 depending on the instrument type, there are many different types of instrument editor:
 

doc/7-systems/opll.md

@@ -13,10 +13,8 @@ the YM2413 is equipped with the following features:
 
 - 9 channels of 2 operator FM synthesis
 - a drum/percussion mode, replacing the last 3 voices with 5 rhythm channels, with drum mode tones hard-defined in the chip itself, like FM instruments. only pitch might be altered.
-
   - drum mode works like following: FM channel 7 is for Kick Drum, which is a normal FM channel but routed through mixer twice for 2× volume, like all drum sounds. FM channel 8 splits to Snare, Drum, and Hi-Hat. Snare Drum is the carrier and it works with a special 1 bit noise generator combined with a square wave, all possible by overriding phase-generator with some different synthesis method. Hi-Hat is the modulator and it works with the noise generator and also the special synthesis. CH9 splits to Top-Cymbal and Tom-Tom, Top-Cymbal is the carrier and only has the special synthesis, while Tom-Tom is basically a 1op wave. 
   - special synthesis mentioned already is: 5 square waves are gathered from 4×, 64× and 128× the pitch of channel 8 and 16× and 64× the pitch of channel 9 and they go through a process where 2 HH bits OR'd together, then 1 HH and 1 TC bit OR'd, then the two TC bits OR'd together, and those 3 results get XOR'd.
- 
 - 1 user-definable patch (this patch can be changed throughout the course of the song)
 - 15 pre-defined patches which can all be used at the same time
 - support for ADSR on both the modulator and the carrier
@@ -37,7 +35,7 @@ the YM2413 is equipped with the following features:
   - `y` is the multiplier.
 - `18xx`: **toggle drums mode.**
   - `0` disables it and `1` enables it.
-  - only in drums chip.
+  - only in drums mode.
 - `19xx`: **set attack of all operators.**
 - `1Axx`: **set attack of operator 1.**
 - `1Bxx`: **set attack of operator 2.**
@@ -69,3 +67,8 @@ the YM2413 is equipped with the following features:
 # info
 
 this chip uses the [FM (OPLL)](../4-instrument/fm-opll.md) instrument editor.
+
+## chip options
+
+- **Ignore top/hi-hat frequency changes**: in drums mode, makes the top/hi-hat channels not write frequency since they share it with snare and tom
+- **Apply fixed frequency to all drums at once**: sets the frequency of all drums to that of a fixed frequency OPLL drums instrument when one note with it is reached

doc/9-guides/README.md

@@ -4,5 +4,9 @@ here is a small collection of useful tricks and techniques to really make Furnac
 
 - [using samples with limited playback rates](limited-samples.md)
 - [choosing emulation cores](emulation-cores.md)
-- [guide on using OPLL patch macro](opllswitching.md)
+- [using OPLL patch macro](opllswitching.md)
-- [guide on using AY/SAA hardware envelope](envelope.md)
+- [using AY/SAA hardware envelope](envelope.md)
+
+# links
+
+- [FM Synthesis of Real Instruments](http://www.javelinart.com/FM_Synthesis_of_Real_Instruments.pdf): an in-depth tutorial on creating FM patches from scratch.