Update README.md

Describe keyjazz special keys & minor fixes

README.md

@@ -2,7 +2,7 @@
 
 m8c is a client for Dirtywave M8 tracker's headless mode. The application should be cross-platform ready and can be built in Linux, Windows (with MSYS2/MINGW64) and Mac OS.
 
-Please note that routing the headless M8 USB audio isn't in the scope of this program -- if this is needed, it can be achieved with tools like jackd, alsa\_in and alsa\_out for example. Check out the guide in file AUDIOGUIDE.md for some instructions on routing the audio.
+Please note that routing the headless M8 USB audio isn't in the scope of this program -- if this is needed, it can be achieved with tools like Pipewire, Pulseaudio, Jack w/ alsa\_in and alsa\_out just to name a few. The file AUDIOGUIDE.md contains some examples for routing the audio.
 
 Many thanks to:
 
@@ -90,12 +90,18 @@ Additional controls:
 * Esc = toggle keyjazz on/off 
 * r / select+start+opt+edit = reset display (if glitches appear on the screen, use this)
 
+### Keyjazz
 Keyjazz allows to enter notes with keyboard, oldschool tracker-style. The layout is two octaves, starting from keys Z and Q.
-When keyjazz is active, regular a/s/z/x keys are disabled.
+When keyjazz is active, regular a/s/z/x keys are disabled. The base octave can be adjusted with numpad star/divide keys and the velocity can be set 
+
+* Numpad asterisk (\*): increase base octave
+* Numpad divide (/): decrease base ooctave
+* Numpad plus (+): increase velocity
+* Numpad minus (-): decrease velocity
 
 ## Gamepads
 
-The program uses SDL's game controller system, which should make it work automagically with most gamepads.
+The program uses SDL's game controller system, which should make it work automagically with most gamepads. On startup, the program tries to load a SDL game controller database named gamecontrollerdb.txt from the same directory as the config file. If your joypad doesn't work out of the box, you might need to create custom bindings to this file, for example with [SDL2 Gamepad Tool](https://generalarcade.com/gamepadtool/).
 
 Enjoy making some nice music!
 
@@ -131,7 +137,7 @@ $ ls -la /dev/ttyACM1
 crw-rw---- 1 root dialout 166, 0 Jan  8 14:51 /dev/ttyACM0
 ```
 
-This shows that the serial port is owned by the user 'root' and the grou 'dialout'. Both the user and the group have read/write permissions. To add a user to the group, run this command, replacing 'dialout' with the group shown on your own system:
+This shows that the serial port is owned by the user 'root' and the group 'dialout'. Both the user and the group have read/write permissions. To add a user to the group, run this command, replacing 'dialout' with the group shown on your own system:
 
     sudo adduser $USER dialout