update audio README.md

audio/README.md

@@ -1,6 +1,6 @@
 # Drum Banks
 
-The drum banks and samples contained in this directory are completely 
+The wave banks and samples contained in this directory are completely 
 modifiable, deletable and reorderable, and you can add your own banks and 
 samples as long as they follow a simple structure.
 Banks and samples are read at runtime, so you do not need to recompile the
@@ -16,12 +16,13 @@ DrumPi for changes to take effect.
       reach some of them!
 - Banks must be in this directory (DrumPi/audio/).
     - Banks in other directories (inc. subdirectories) will not be read.
-- Banks must contain (at least) 8 .wav files with the names detailed below.
+- Banks must contain (at least) 4 .wav files with the names detailed below.
 
-## Samples:
-- A 'sample' is a .wav (audio) file.
-- Each bank must contain 8 .wav files, with the names `drum1.wav`, `drum2.wav`
-  etc, up to `drum8.wav`.
-- These samples are triggered by the drum keys `asdfjkl;`, respectively.
-    - E.g. `drum1.wav` is triggered by the `a` key, `drum2.wav` by the `s` key
-      and so on.
+## Waves:
+- A 'wave' is a .wav (audio) file.
+- Each wav file should be a single cycle waveform recorded at 48kHz playing at A2=110Hz.
+- Each bank must contain 4+ .wav files, with the names `wave1.wav`, `wave2.wav`
+  etc, up to `WaveN.wav`.
+- These waves are played at a frequency dictated by the midi note number and individual samples of the wave files are interpolated according to the morph parameter (mapped to a physical midi CC control)
+    - E.g. the midi note number 33 is played which sets the playing speed of the wav files in the active bank to A0=22.5Hz
+      then the morph paramater ranges 1 to N (number of wave files)  and its value set the amount of interpolation between the different parallel wave samples; (eg if morph =  only wav file 1 is heard, if morph =1.6 then an interpolation is made with 0.4 weight to wav 1 and 0.6 weight to wav 2 and so on).